Yea pretty simple & easy on your truck, I just changed one on my 1991 Chevy G20 custom van & the hard part was getting the damn doghouse off because my passenger side front seat the electric switch to make it go back doesn’t work all the other switches on the seat work except that one so it was a pain in the but to get the doghouse off, i went & bought a 1/4 inch deep socket & it was easy peasy the doghouse was the hard part!
88 step side 350v8 5.7, So I’ve replaced what most people have said in the comments but I’m having a rough start, idling and shutting off. Just put the new iac in and still shuts off, checked map sens and egr sens, checked the vac lines, pulled out the sensor and got the codes when I did each one. Including the iac. I had felt some shaking so I took it in and the spark plugs were bad and not gaped right, so I replace that shaking went away, took off throttle body cleaned it, changed regulator, clean injectors, put in back together and will start run for a minute then shut off again, tried going in reverse and it shut off again, what he’s the spray from the injectors looks umbrella like and normal. I don’t know what else to check or how to keep it running. Please help. I work Monday and I today and tomorrow to fix it.
when you shut it off do the injectors leak? as long as your fuel is a nice fine mist that should be fine as long as there are no drips. have you checked the knock sensor on the lower left side of the block in front of the starter? what about the ignition control module?
Mine is doing the exact same thing and have replaced all sensors, plugs ecm O2 idle control valve ,Idle position sensor,map sensor, temp sensor, fuel pump and relay, distributor cap and rotor , ignition module and no change. I am out of things to try. Still starts and idles for 5 sec and then dies. Injectors we’re replaced as well. Any thoughts or solutions???
Have a 95 Sierra TBI. Idle drops when letting off gas to around 500 rpm and sputters a little. Usually doesn't stall but if I'm going slow enough it can.
@@atomicrooster typically a new iac should cause an issue unless its bad or its is now showing you have an issue somewhere. the only down side to tbi is chasing demons, its can be tricky. lightly tapping the tps is one trick, watch the temp gauge for a faulty temp sending unit, check the plastic vaccum lines they can crack and be hardly noticeable
My dad’s 87 TBI 350 has an erratic idle for about 2 minutes after starting it up. Some background: It’s a no plate yard truck and he doesn’t keep the battery in it, mice filled the air intake at one time and he had three loose spark plugs. It was basically not starting and ran very poorly when it did manage to start. I put all new ignition parts on it and changed all the plugs, and now it starts really nicely but the idle goes very low, then surges, over and over up and down until it gradually evens itself out. This cold idling issue is not original to the truck, but it has been going on for a couple years before I replaced the cap and rotor, coil and plugs. I ordered a new IAC valve, but I was wondering if you thought that was more an O2 sensor or maybe constantly resetting the EFI computer? Thank you for the excellent how-to video.
Well it could be several things, like the iac inside of where it goes could be filled with who knows what now and needs cleaned out. If miced filled the intake tube how long did ti sit. If it sat for awhile there could be a number of things like the fuel regulator dried out. Make sure the injectors have a steady stream and no drips, cracked vacuum lines for the map, and egr. o2 would make it rich or lean but still an option. Consistently resetting is also not good.
I have a '93 S10 4.3 and it idles like it has a thumping camshaft in it, it seems to run fine though. It did one day not want to start for me after driving about 30 minutes, it had to sit a few minutes then it fired right back up.
Mine has done the same thing. It was my IAC. The spring was stuck extended not allowing enough air into the system causing it to either idle rather low and sometimes not start.
92 GMC 5.7. Service engine soon light recently started coming on a few seconds after start up. Accompanying the light, idle drops off and surges. Part throttle, it misfires and generally runs like crap. Heavier throttle application it seems to smooth out. Was told O2 sensor, but made no improvement. Has recent cap, rotor, plugs, wires and fuel filter. Mechanic buddy pulled and cleaned the IAC and problems started then. It’s an intermittent issue (or was), but now it seems to be most of the time. IAC replacement?
sometimes cleaning will hurt it. if it was cleaned it got worse i would start there, and check your stream on the injectors. if its a mist injectors are ok, if it has drops of fuel and mist it could be injectors or fuel delivery
but what if its like a situation where my 454 1994 suburban 2wd. ..sudden bad idle and dies on road and when put ingear. even after warm up or being cold. issue was fixed by a temp sensor infront and now prob is back. with all same ignition and vac original parts still on. old wires old plugs cap rotor dist. all old . but i check the temp sensor and its working fine. or seems it is. even a new one tested next to old temp same results so i didnt replace it again. ..ever since i replaced every part ican find since its cheaper to do so than taking to shop and paying hundreds to change a part if i had to. so all new parts now even new whole dist. wires all of it. oil change gaskets to tbi. no leaks. fuel psi good 19-20. has built in fuel test port.super nice. still same prob. and every part changed. no vacuum leaks. good hoses triple checked. timed and idle screw cap is still in place from factory never touched. please help.
alright, have you checked the grounds and wiring to the temp sensor? injectors themselfs? knock sensor? what transmission 700r4 wont have vacuum but if it has a 350 turbo if they had them then it would have a vacuum line to the diagram.
Efurd i got an 87 350 tbi i changed dizzy water pump ignition coil coolant temp sensor, i got this machine gun noise when i accelerate ticking noise, with a mild backfire, any help?
since you put a new distributor in it could be slightly out of time, if you didnt get it 100% where it was when it was taken out it could be off and you may need to rest time on it by disconnecting the wire under the dash. you may have to look that up i dont do it enough to remember it off the top of my head
My 1989 suburban has this same engine. It idles fine, but then when I put it in any gear, it immediately dies. If I keep the engine revved up a little when putting it in gear, it will drive. Probably this idle air control?
@@EfurdGarage it finally threw OBDI code 32 for the EGR valve. Only took 3 days. Mighta did some damage in that area replacing my ICM on the roadside in the dark the other night. I really appreciate guys like you that make this type of content. I know a little about video making, and cheers to you for taking time and effort. It has helped me avoid mechanic cost my whole adult life. To hell with them rich men north of Richmond.
@@jimmywaynegarrett8024 yea in the dark is not always the best.... But being roadside you dont have a choice. Thank you im glad the videos can help, thats is what they are there for.
Man I got a 1993 gmc sierra 4.3 tbi straight piped everything else is stock, I have been having a problem where when I turn it off for a hour after warming it up, it wont stay running. I figured out through trial and error that if I unplug my IAC valve and plug it back in my truck will start and run fine no matter what, so I changed the iac valve but it does the same thing with the new one, im not sure what to do
@@EfurdGarage when you say “reset it’ll do you mean the Iac valve or the computer of the truck? I unplug the battery so that should reset the computer but I’m not sure on how to reset the iac valve I’ll have to check the books.
@@Nowz20183 yea check the books because its odd what you hear how to reset it, i was always taught they reset them self's after driving them. others swear there is away to do it manually. If you got the book i would check it
@EfurdGarage AutoZone the website told me it was a fit for my k2500 7.4 1994 suburban, I got it today by delivery and it is not the same, do you know which throttle body I might have based on my model? I'll see if I can return it or exchange it for store credit. I changed my THROTTLE POSITION SENSOR tho.. and it feels so different, like magic like a miracle, literally the check engine light has not appeared since I replaced the TPS (today an hour ago it's crazy, I'll see in the morning (cold weather how it goes but wow, I'm loving motors), my emission failed by like 40 points everything else passed, air valve is next and then O2 sensor, if they check engine light doesn't show up tomorrow morning I'ma take it straight to the smog station again
@PlayerGamePlayNoCommenta-sw1pf well the 454 throttle body is different then small block throttle body. Check with summit racing its much better at getting the right parts
Seeing that you kinda help everyone out. Having a problem with a 94 gmc. Kinda fluctuates when idling. I personally think it’s a cracked flywheel personally but it could be a bad iac
mostly a cracked flywheel or flexplate will cause vibrations and noise not fluctuations. includes loose. alot of times the crack will cause a noise as if you almost have a rod knock as a lot of people would describe it
@@EfurdGarage I shall start with the IAC. Just doing my research from looking at this comment section. It doesn’t die but I just got it like a month ago and going through it fixing the problems and this was one that stumped me for a bit. Done a complete tune up with new wires and plugs but runs fine just when it’s idleing it fluctuates. It’s overall pretty tight of a truck.
@@Teenagewasteland1000 they can be good engines and last a long time. I beat the ever loving crap out of this one. Tbi can be tricky sometimes not like todays efi where you can plug in a reader. The early tbi efi takes a little more patience
@@EfurdGarage yeah I’m just learning about the built in OBD with a paper clip. My dad gave me a chevelle that’s pretty ratty but I’m building it up. Then went to dailying a 02 Monte ss. Loved my monte but the harsh winter. Only reason why I went with the OBS because it is old enough to look cool but new enough to have things like cruise AC plus the incredible amount of aftermarket support
350 tbi here. Lately it’s doing this thing where if I’m stopped and the engine is warming up or warmed. Light throttle has a hesitation after about a second, if I throttle aggressively it gets through it, but if I floor it, it bucks until I take off my foot and it clears. No CEL. And my idle is low. Maybe one hash mark about the bottom line on my tach. Any help from anywhere would be appreciated. Already replaced my coolant temp sensor. I’m thinking possibly tps or iAc. But I’m not sure with these
@@EfurdGarage I pulled my iAc. Looked pretty clean. Still cleaned and dried with b12. Plugged it back in. Ran the same. I went to pull the hose off the egr and it caught the harness by the iAc and it immediately threw a cel and ran terrible. I think my issue or one of which is my wiring
Just found your video. I have a 91 C1500, 350 tbi. Starts and revs fine, but all of a sudden it wont idle. Starts up fine, but dies in 10-20 seconds at idle. Unknown history on truck, but it stalls at stops. Is the iac my problem. Had a leak in trans pan, fixed that and fluid level good. test drove easy to flow fluid through gears and system. Shifts fine. Started running rough once I gave it the beans for passing gear on highway, Pulled over and restarted truck is when this problem started. I can fix most things on truck, but never worked on tbi, so I`m clueless. Looking for direction to take. I`ve heard iac, tps, etc. Wish it had a carb, I would not be lost. Money light is NOT on. I`m not a parts cannon guy, dont have money to burn right now during COVID...laid off. Do I have to rebuild tbi unit? I have owned this truck for 3 years, 1st problem Thanks for sharing, stay safe.
iac really shouldnt affect it while driving, first thing i would look at is the injectors, if there is a nice fine mist look else where, if there are drops from the injectors it is usually bad injectors. you can rent a pressure tester and check fuel pressure to check the pump, the tbi has a built in regulator which is something to look into. tps you can unplug and see what happens or very lightly tap it and see if anything changes. since i cant look or hear the truck one thing that comes to mind is that it could be in the fuel system since you opened it up and let fuel in fast something could have happened, particles in the filter or injector. rush of fuel damaged regulator diaphragm (who knows if its factory still or not alot of people never rebuilt the tbis so issues have popped up more often)
It has a singular clip that locks it in place should only go on one way. If the clip is broke off just look for where it was and line it up the the notch sticking up on the sensor
When i put it back on I tightened it too much and the brass broke off and i tried cutting it off with a sawzall but now the inside part is stuck inside the throttle body. Help!
so you still need to un thread the brass inside? well depends on whats all there your going to need to move stuff and make room. brass is soft and you just want to make sure you dont damage the aluminum threads of the throttle body. either use something to grab whats left and twist out or fine something that expands counter clock wise and use that. Now if you are talking about the spring and valve you will just need to unbolt the tbi there is a passage for the idle air and you should be able to get the parts out there
I replace the iac and then I start the truck it was running at high idle , so I took it up the road and drove it hard , drove it back home it seems like running normal idle but the engine light still on and is that how you The computer puts a relearn after replacing the iac ?
@@robertgameworld you may have to rest it Depress the accelerator pedal slightly. Start the engine and run for 5 seconds. Turn the ignition switch to the OFF position for 10 seconds. Restart the engine and check for proper idle operation.
Question, would a bad IAC cause my 350tbi to not start when it’s warm? I end up having to hold it to the floor when cranking to get it to go. Cold starts and runs perfectly after it starts.
I have an 89 GMC Sierra 5.7 TBI. I HAVE REPLACED everything electronically as well as the computer and all the fuel components, only idle issue I’m having now is a bad surge at a normal RPM idle. Iac maf tps all have been replaced as well but I did order the cheapos offline but I have multiple I have switched back and forth and still does the same thing I need help getting this gem back on the road safely if anyone has any tips or tricks please and thank you.
could be one of many reasons, it should idle up when that pull from the ac is on. So its a good place to look as well as vacuum leaks. or just needing a tune up
@EfurdGarage Thanks man I will check the iac valve. I don't think I have a vacuum leak . But I also have an aftermarket msd distributor so I don't know how long those last. That's another thing I have to check
Idle comes down to normal after IAC reset procedure. But when I shut truck off and restart high idle returns. Swapped out IAC and same issue. Is that a bad ECU? Thanks.
Thanks for the response. Timing is set. Will check TPS. I don't think the TPS would produce this scenario where IAC forgets the relearn after shutting off and restarting. Will research some more though. Thanks
I have a quick question my 92 Chevy has a 350 engine in it and it stays dying when I got a stop was wondering if this would be the problem wanted to make sure before I start spending money
Mine is idling very high would that also be the issue? Edit: thank you to this video and the people in the comments. I did fix it after driving it for a while it started giving me the rough idle and bogging thankfully it didn’t stall out I got it fixed and it runs way better thanks guys
So idk if anyone can help but I’ve rebuilt my tbi changed throttle body sensors new jets and new coolant sensors but it still has a hard time idling and it seems like it’s dumping way to much fuel it’ll blow black smoke while it’s trying to idle properly when it over loads and some days it’s just fine but the idle will fluctuate up and down. I’m not sure if it’s fuel pump or something to do with my tbi but I have not changed this sensor yet
Check the fuel while its running. You should habe a nice fine mist out of the injectors. If you have drops of gas or a stream you either have a bad injector or the seal around it is bad allowing the fuel to go around the injector and into the intake. Make sure the regulator is ok. You should have gotten a new one with the rebuild kit make sure its in correctly
@@EfurdGarage I have a fine mist I replace everything on the top side of the tbi but I haven’t looked into the bottom part of the tbi. Idk if I should look into replacing the old one for a new one or convert it to a carburetor. Tbh idk what’s wrong with it. I’ve done a lot of work on it and still have a fuel issue, bogs idles high and sometimes it won’t crank and smells like it’s flooded but the jets mist
Why does my 95 sierra 5.7 go up in revs when i start it up and doesnt go back down to normal revs before changing this? It also wants to go by itself when in drive (faster than normal)?
Great video! Thanks for posting. I have an issue with my truck (1991 V10 Blazer TBI): at startup the idle constantly goes up and down, up and down. When I drive it for 10 to 15 minutes the issue goes away. When I shut it off and it sits for 30 minutes the issue comes back. The OBD1 doesn't give me no error codes and the spray mist of the injectors look ok. Could the IAC be the issue? Any input is appreciated!
@@EfurdGarage Why the Temperature Sending Unit? I had replaced it because it was not working with a new one and I think that's when fast idle started. Plus Temp Unit not reading full temp at dash gauge. Any ideas?
@@tedday2008 there are 2 on the tbi on for the gauge and one for helping control how much fuel to dump. I would check the ground that is close to the intake manifold temp sensor as well as the harnesss. And check the harness on the one at the drivers side cylinder head
Hi there i have a the same motor i just installed in my 91 Chevy truck. The truck cranks but won't start unless i used starter fluid, what do i have wrong.
you will want to check a few things, if it runs by adding fuel then its a fuel delivery issue which i would start with the pump and filter, then the regulator thats in the throttle body, and injectors. you should be getting a nice even mist from the injectors no drops or streams.
How did you know idle control valve was faulty? Did you test it with a meter? Apply voltage to actuate valve ? I’m asking cause I’m seeing people replacing valves by sight or suspicion. I’m looking for a true test to determine if it’s bad or not, but haven’t found anything yet. Good demonstration on replacing one though. Thanks.
This engine had a rough idle with a new tune up. Thats why i did it on this one. Also i have a habit of changing them because alot of people tend to forget about them or dont know they exist. I am sure there is a way to test with a meter
hey man have a question off topic off the video. i also have a tbi 89 k1500.do u think a well tuned quadrajet can deliver better mpg then a tbi?just wanted ur opinion from someone else who also owns both.i have found a well tuned quadrajet can do it.
if i recall in 87 when they switched to tbi from the 86 qjet in the trucks gas mileage dropped 1-2 mpg. driving them i have had better luck with mpg out of the qjet when keeping your foot out of it. also the qjet has more power potential. only time i saw tbi do better on fuel is really cold winters and sitting in traffic alot.
@@EfurdGarage The qjet allows more air flow. this factor gets better mpg. I changed an old '65 Mustang 289 2bbl to an autolite 4bbl by ford and got way better mpg's.....as long as you kept your foot out of it. Foot in.....hang-on!!!!!
Hello. I have a little issue. I am replacing the IAC valve connector and the stock wires are all green while the new one is color coordinated. I was going to cut and splice 1 wire at a time but by the time I got home all 4 wires were cut. How the heck do I figure out what wire goes where or does it even matter? Thanks for the help.
It does, and i am not 100% sure but i found this from an old forum. short A & B together on the ALDL and key-on, engine-off. The IAC should continuously step toward the closed (extended) position. If you do this with the IAC out of the TB the pintle will shoot out and find the most in-acccessable recess in the corner of your garage. If this test fails by the IAC stepping toward the open (retracted) position, swap two of the alike colored wires. Either the blue/blk with the blue/wht or the green/blk with the green/wht. If the IAC fails to step at all, you can try different wiring setups until it steps. Then check the direction as above. The stepper has two coils. One each on a pair of wires. With a DVM can measure the pins until 2 are found that have some resistance (40 ohms? I forget). Put a pair of wires on those pins, and the other pair of wires on the other pins. Then proceed with the direction check.
There should be a small little tab/nipple/nub sticking out that the tab slides over. The harness although broke should see where it was broke and line up the broke side to the other side
Got a question I hope you can answer. I just changed out my Idle Air Control Valve on my 1990 Full Size Blazer with the same replacement valve you just changed out. I did so because I went on You Tube just last week and asked the Question why my Full Size 1990 Blazer Idles so high and the You Tube Video said that the Idle Air Control Valve was bad and the reason why I replaced it today. Problem is I don't notice any difference. Its been like this a long time but I don't drive my Blazer very much. It only has 65k miles on it believe it or not. I purchased it back in 1995 at 5 years old. It has been idling high probably the last 15-20 years and I had no idea what to do to get it down being it is not a carburetor but throttle body fuel injection and didn't know of any adjustments. Being I didn't touch anything to make it idle fast I thought it was something else causing it. Did I do the right thing by replacing the Idle Air Control Valve for my problem? I thought that maybe the new replacement may have a problem but I just don't know at this point.
I would look into your throttle postion sensor, engine coolant temp sensor. Maybe the regulator which is in the throttle body. If its that low mileage and it has been doing it that long sounds like a faulty part from the factory that never got replaced. Wd40 around the trottle arm make sure its moving properly. Could also be a vaccum leak, You may want to check and or replace the throttlebody to intake gasket. Make sure the bolts holding the throttle body are thight. Make sure the intake bolts are tight. Check the vaccum lines to the map sensor and brake.
I have a 91 4.3 with throttle body, the truck idles high when in park and when i put into drive it stalls out. Goes away after a few tries thoufh and it will Hold in gear. Could this be because of this or the tps.
I have 93 gmc yukon 5.7 TBI and when I fire it up in the morning it stalls out so I gotta keep the gas pressed a bit put it in drive real quick then put it back to park and the rpm idle is super low like at 100 or 200 rpms what can cause that?
Hey love your channel! 😁🤝 I have a 1987 chevy g20 van 5.7 liter TBI. Lately I’m noticing when I ride a little while , my van becomes hesitant especially when stopping then starting at stop signs. When I just coast and cruise it acts hesitant in and out like it wants to cut off(but doesn’t). And my service light is on.? Where should start?
Thanks You! well if you can get a scanner on it sometimes it works to tell you. I would check the map first and make sure the injectors are a fine mist with no drips. also check all hoses/tubing for vacuum leaks.
Good video friend I told you that once I washed the housing where this iac valve is screwed in my chevrolet celebrity 1988 2.8 and when reinstalling it I pressed it with the force of my hand and the car feels too unstable, it accelerates a lot when turn it on and when making changes ... So may that be why there is an air leak and what he mentioned happens to me? So you have to squeeze something hard, right?
im not to familiar with the 2.8, but yo shouldn't have to squeeze anything hard. It should just screw it with the washer and the harness plug in. make sure you have the washer and the harness is plugged in correctly
I know this video is a bit old but really needing some insight here 1994 wt2500 305tbi For the last month or so My throttle positioning sensor would act up for the first 5 minutes of driving, throttle would cut out and kick back on for a few minutes while at low throttle highway cruising speed and then it would straighten up and run fine but it was drinking fuel pretty bad so I swapped the tps and it immediately made things 10x worse, it was bucking real bad and was a total pooch unless I had it up above 2k rpms, so I swapped back to the old tps and it’s still bucking and doing the same thing it was with the new tps. Tested the old tps with a multimeter and it has 0.75v at no throttle and slowly increases voltage as I increase throttle like it should and does not seem to have any dead spots throughout the throttle range, so I’m completely stumped, anyone ever experience anything like this?
Ecm flashed code for iac and I swapped it. Now it's worse. And won't start without flooring also got an erroneous code for cts being below threshold 1994 c1500 4.3
@@lancegodbey6450 Did you clean inside of the throttle body? also check the wiring to make sure nothing is damaged and all the connectors are connecting
Hello, I have a 1993 GMC G2500 5.7. Were having issues with the IAC we replaced it with a new one, checked wires, vaccume lines, and our obd says the TPS is fine. It starts but wont run due to the IAC being all the way open at 150. Any thoughts? Thank you in advance!
Could be a new faulty iac or bad ground. Have you tried disconnectimg the battery to reset it or turning the key on for 2 seconds off for 10 and repeat and see what happens
@@EfurdGarage okay, i saw other guys connect a wire in 2 ports, of a connector under the dash, so you could set the idle rpm. Already thought why? Install new one and should be alright i thought.
@@Petrolhead350cui yea with the idle air it has always been a plug and go. The wires under the dash are for resting the timing which is for the distributor
@@jessebenjamin4779 summit racing has a good verity of them. You can get a one piece in the size you need, or spectre makes a set of 3 that you can mix them around to get various heights.
It was faster then most expected especially on the highway. I never had a good set up to keep it from spinning when i had it at the track. But it could smoke the tires with ease and get over 20 mpg at 65mph.
I have a 91 Sierra c1500 with the same engine and when I replaced the IAC the truck ran so bad almost like it had a serious vacuum leak. When I asked around I was told that upon replacing the IAC that there were steps to take after installing it. Any recommendations? Thanks in advance
Efurd Garage In the video you said you heard not to apply cleaner to the actual IAC that’s why I was asking cause I saw other videos were they said you could. Mines a 91 caprice seems I just cleaned it but it seems old I’m just gonna replace it with a new one along with the map sensor. Seems to be running better since I cleaned everything with carb cleaner tho.
@@str8profit81 yea i have heard not to. But i have yet to ever try and forgot that honestly. I dont know anyone personally that has cleaned it like that so i dont know any short or long term effects
yes i mean 350 tbi, 350 with throttle body injected. not a 350 with a carburetor, and not a 350 tp,i 350 with tune port injected. But a 350 cubic inch displacement that is throttle body injected i am referring to the engine as a whole , as it is my setup.
@@jotegg1276 😆 honestly.... You would be surprised the people.... Well you beem on the Internet im sure you seen them i really probably dont have to explain
@@EfurdGarage I got into with some dummy who insisted that gm did not make a 1994 Blazer 1500 Silverado model. There's no such vehicle! Lmao Still figuring out my issue with idle.
Thank you again for the knowledge! Seems that everything I need to do on my 94 Silverado you have a very informative video for so cool!!!
Your welcome glad i could help
Yea pretty simple & easy on your truck, I just changed one on my 1991 Chevy G20 custom van & the hard part was getting the damn doghouse off because my passenger side front seat the electric switch to make it go back doesn’t work all the other switches on the seat work except that one so it was a pain in the but to get the doghouse off, i went & bought a 1/4 inch deep socket & it was easy peasy the doghouse was the hard part!
yea if you cant access the dog house it can be difficult. but once you open the dog house sometimes its easier then reaching over the engine bay.
Appreciate this video and really simple to do. 1988 GMC Suburban V2500
Glad it could help
Thanks for the tip going to do that on my 95 chevy 1500 thank you
Glad to help
88 step side 350v8 5.7, So I’ve replaced what most people have said in the comments but I’m having a rough start, idling and shutting off. Just put the new iac in and still shuts off, checked map sens and egr sens, checked the vac lines, pulled out the sensor and got the codes when I did each one. Including the iac.
I had felt some shaking so I took it in and the spark plugs were bad and not gaped right, so I replace that shaking went away, took off throttle body cleaned it, changed regulator, clean injectors, put in back together and will start run for a minute then shut off again, tried going in reverse and it shut off again, what he’s the spray from the injectors looks umbrella like and normal. I don’t know what else to check or how to keep it running. Please help. I work Monday and I today and tomorrow to fix it.
when you shut it off do the injectors leak? as long as your fuel is a nice fine mist that should be fine as long as there are no drips. have you checked the knock sensor on the lower left side of the block in front of the starter? what about the ignition control module?
Mine is doing the exact same thing and have replaced all sensors, plugs ecm O2 idle control valve ,Idle position sensor,map sensor, temp sensor, fuel pump and relay, distributor cap and rotor , ignition module and no change. I am out of things to try. Still starts and idles for 5 sec and then dies. Injectors we’re replaced as well. Any thoughts or solutions???
@@barrygooden8459 did you ever figure yours out?
Have a 95 Sierra TBI. Idle drops when letting off gas to around 500 rpm and sputters a little. Usually doesn't stall but if I'm going slow enough it can.
Well this is one thing. Also your tps. Look at the stream coming out of the injectors and see if its a fine mist or has drops
@@EfurdGarage has new injectors. I'll check the tps. And pcv valve while I'm at it
@@atomicrooster i usally suggest looking at the injectors becuase its over looked.
@@EfurdGarage replaced IAC, now it's idling really high. Drove it on the interstate to try to reset.
@@atomicrooster typically a new iac should cause an issue unless its bad or its is now showing you have an issue somewhere. the only down side to tbi is chasing demons, its can be tricky. lightly tapping the tps is one trick, watch the temp gauge for a faulty temp sending unit, check the plastic vaccum lines they can crack and be hardly noticeable
exactly what i needed! thank you! not sure if im the first to say it but i love that your rockin the Type O Negative shirt! rock on!
I hope it helped. Not the first but not many people have said anything, you maybe the 2nd or 3rd lol
Good to know in case I ever end up with a TBI V8, thanks for the tips man!
no problem, thanks for stopping by
Funny to see you here lol
I love your t-shirt!!!
TON!!!!
I thought you are supposed to do a relearn on the iac valve. I changed mine and now getting intermittent check engine light.
I have never had to, but you can try disconnecting the battery. But it could have also reveled another issue
Thanks sooooo much you saved us much grief
Glad it could help
My dad’s 87 TBI 350 has an erratic idle for about 2 minutes after starting it up.
Some background:
It’s a no plate yard truck and he doesn’t keep the battery in it, mice filled the air intake at one time and he had three loose spark plugs. It was basically not starting and ran very poorly when it did manage to start.
I put all new ignition parts on it and changed all the plugs, and now it starts really nicely but the idle goes very low, then surges, over and over up and down until it gradually evens itself out. This cold idling issue is not original to the truck, but it has been going on for a couple years before I replaced the cap and rotor, coil and plugs.
I ordered a new IAC valve, but I was wondering if you thought that was more an O2 sensor or maybe constantly resetting the EFI computer?
Thank you for the excellent how-to video.
Well it could be several things, like the iac inside of where it goes could be filled with who knows what now and needs cleaned out. If miced filled the intake tube how long did ti sit. If it sat for awhile there could be a number of things like the fuel regulator dried out. Make sure the injectors have a steady stream and no drips, cracked vacuum lines for the map, and egr. o2 would make it rich or lean but still an option. Consistently resetting is also not good.
I have a '93 S10 4.3 and it idles like it has a thumping camshaft in it, it seems to run fine though. It did one day not want to start for me after driving about 30 minutes, it had to sit a few minutes then it fired right back up.
I cant be 100% sure since i dont see or hear it. But i would suggest checking the ignition module
Mine has done the same thing. It was my IAC. The spring was stuck extended not allowing enough air into the system causing it to either idle rather low and sometimes not start.
Try replacing the temp sensor (not the one for the temp gauge) my truck did the same things as yours, and this fixed the problem.
Where did you get that air cleaner
just a regular air cleaner i modified not a great video but here it is ua-cam.com/video/RAtoiMGGiGc/v-deo.html
92 GMC 5.7. Service engine soon light recently started coming on a few seconds after start up. Accompanying the light, idle drops off and surges. Part throttle, it misfires and generally runs like crap. Heavier throttle application it seems to smooth out. Was told O2 sensor, but made no improvement. Has recent cap, rotor, plugs, wires and fuel filter. Mechanic buddy pulled and cleaned the IAC and problems started then. It’s an intermittent issue (or was), but now it seems to be most of the time. IAC replacement?
sometimes cleaning will hurt it. if it was cleaned it got worse i would start there, and check your stream on the injectors. if its a mist injectors are ok, if it has drops of fuel and mist it could be injectors or fuel delivery
Check egr valve
my iac valve connector is breaking apart...can I just splice the wires with a new connector???
you can, or buy a new connector that the old wires slide into. summit racing and lmc should have one
@@EfurdGarage thank you Mr Furd
but what if its like a situation where my 454 1994 suburban 2wd. ..sudden bad idle and dies on road and when put ingear. even after warm up or being cold. issue was fixed by a temp sensor infront and now prob is back. with all same ignition and vac original parts still on. old wires old plugs cap rotor dist. all old . but i check the temp sensor and its working fine. or seems it is. even a new one tested next to old temp same results so i didnt replace it again. ..ever since i replaced every part ican find since its cheaper to do so than taking to shop and paying hundreds to change a part if i had to. so all new parts now even new whole dist. wires all of it. oil change gaskets to tbi. no leaks. fuel psi good 19-20. has built in fuel test port.super nice. still same prob. and every part changed. no vacuum leaks. good hoses triple checked. timed and idle screw cap is still in place from factory never touched.
please help.
alright, have you checked the grounds and wiring to the temp sensor? injectors themselfs? knock sensor? what transmission 700r4 wont have vacuum but if it has a 350 turbo if they had them then it would have a vacuum line to the diagram.
There’s a little star shaped screw on the right you can also turn that to the left a little
true
Efurd i got an 87 350 tbi i changed dizzy water pump ignition coil coolant temp sensor, i got this machine gun noise when i accelerate ticking noise, with a mild backfire, any help?
since you put a new distributor in it could be slightly out of time, if you didnt get it 100% where it was when it was taken out it could be off and you may need to rest time on it by disconnecting the wire under the dash. you may have to look that up i dont do it enough to remember it off the top of my head
My 1989 suburban has this same engine. It idles fine, but then when I put it in any gear, it immediately dies. If I keep the engine revved up a little when putting it in gear, it will drive. Probably this idle air control?
Its a possibility but seems more like a vacuum leak
@@EfurdGarage it finally threw OBDI code 32 for the EGR valve. Only took 3 days. Mighta did some damage in that area replacing my ICM on the roadside in the dark the other night.
I really appreciate guys like you that make this type of content. I know a little about video making, and cheers to you for taking time and effort. It has helped me avoid mechanic cost my whole adult life.
To hell with them rich men north of Richmond.
@@jimmywaynegarrett8024 yea in the dark is not always the best.... But being roadside you dont have a choice. Thank you im glad the videos can help, thats is what they are there for.
My tbi 350 wont shift out of 1st after it gets hot,what are some things to check
do you mean hot, or up to temp? What transmission does it have?
Man I got a 1993 gmc sierra 4.3 tbi straight piped everything else is stock, I have been having a problem where when I turn it off for a hour after warming it up, it wont stay running. I figured out through trial and error that if I unplug my IAC valve and plug it back in my truck will start and run fine no matter what, so I changed the iac valve but it does the same thing with the new one, im not sure what to do
Either have to reset it or yo need to clean out the air passage back there
@@EfurdGarage when you say “reset it’ll do you mean the Iac valve or the computer of the truck? I unplug the battery so that should reset the computer but I’m not sure on how to reset the iac valve I’ll have to check the books.
@@Nowz20183 yea check the books because its odd what you hear how to reset it, i was always taught they reset them self's after driving them. others swear there is away to do it manually. If you got the book i would check it
I have a 1994 silverado 7.4 I need to do this, i was scared but not anymore thanks
awesome glad it could help
@EfurdGarage AutoZone the website told me it was a fit for my k2500 7.4 1994 suburban, I got it today by delivery and it is not the same, do you know which throttle body I might have based on my model? I'll see if I can return it or exchange it for store credit. I changed my THROTTLE POSITION SENSOR tho.. and it feels so different, like magic like a miracle, literally the check engine light has not appeared since I replaced the TPS (today an hour ago it's crazy, I'll see in the morning (cold weather how it goes but wow, I'm loving motors), my emission failed by like 40 points everything else passed, air valve is next and then O2 sensor, if they check engine light doesn't show up tomorrow morning I'ma take it straight to the smog station again
@PlayerGamePlayNoCommenta-sw1pf well the 454 throttle body is different then small block throttle body. Check with summit racing its much better at getting the right parts
Thank you, sir.
Thanks for watching
Seeing that you kinda help everyone out. Having a problem with a 94 gmc. Kinda fluctuates when idling. I personally think it’s a cracked flywheel personally but it could be a bad iac
mostly a cracked flywheel or flexplate will cause vibrations and noise not fluctuations. includes loose. alot of times the crack will cause a noise as if you almost have a rod knock as a lot of people would describe it
@@EfurdGarage I shall start with the IAC. Just doing my research from looking at this comment section. It doesn’t die but I just got it like a month ago and going through it fixing the problems and this was one that stumped me for a bit. Done a complete tune up with new wires and plugs but runs fine just when it’s idleing it fluctuates. It’s overall pretty tight of a truck.
@@Teenagewasteland1000 they can be good engines and last a long time. I beat the ever loving crap out of this one. Tbi can be tricky sometimes not like todays efi where you can plug in a reader. The early tbi efi takes a little more patience
@@EfurdGarage yeah I’m just learning about the built in OBD with a paper clip. My dad gave me a chevelle that’s pretty ratty but I’m building it up. Then went to dailying a 02 Monte ss. Loved my monte but the harsh winter. Only reason why I went with the OBS because it is old enough to look cool but new enough to have things like cruise AC plus the incredible amount of aftermarket support
350 tbi here. Lately it’s doing this thing where if I’m stopped and the engine is warming up or warmed. Light throttle has a hesitation after about a second, if I throttle aggressively it gets through it, but if I floor it, it bucks until I take off my foot and it clears. No CEL. And my idle is low. Maybe one hash mark about the bottom line on my tach. Any help from anywhere would be appreciated. Already replaced my coolant temp sensor. I’m thinking possibly tps or iAc. But I’m not sure with these
tps sounds like the place to start, or o2
@@EfurdGarage thank you. I will try thay
@@SirGuidemere91 if not those maybe the knock sensor
@@EfurdGarage I pulled my iAc. Looked pretty clean. Still cleaned and dried with b12. Plugged it back in. Ran the same. I went to pull the hose off the egr and it caught the harness by the iAc and it immediately threw a cel and ran terrible. I think my issue or one of which is my wiring
@@SirGuidemere91 as old as those trucks are now wiring issues can be a thing. I would take my time and look everything over
Just found your video. I have a 91 C1500, 350 tbi. Starts and revs fine, but all of a sudden it wont idle. Starts up fine, but dies in 10-20 seconds at idle. Unknown history on truck, but it stalls at stops. Is the iac my problem. Had a leak in trans pan, fixed that and fluid level good. test drove easy to flow fluid through gears and system. Shifts fine. Started running rough once I gave it the beans for passing gear on highway, Pulled over and restarted truck is when this problem started. I can fix most things on truck, but never worked on tbi, so I`m clueless. Looking for direction to take. I`ve heard iac, tps, etc. Wish it had a carb, I would not be lost. Money light is NOT on. I`m not a parts cannon guy, dont have money to burn right now during COVID...laid off. Do I have to rebuild tbi unit? I have owned this truck for 3 years, 1st problem Thanks for sharing, stay safe.
iac really shouldnt affect it while driving, first thing i would look at is the injectors, if there is a nice fine mist look else where, if there are drops from the injectors it is usually bad injectors. you can rent a pressure tester and check fuel pressure to check the pump, the tbi has a built in regulator which is something to look into. tps you can unplug and see what happens or very lightly tap it and see if anything changes. since i cant look or hear the truck one thing that comes to mind is that it could be in the fuel system since you opened it up and let fuel in fast something could have happened, particles in the filter or injector. rush of fuel damaged regulator diaphragm (who knows if its factory still or not alot of people never rebuilt the tbis so issues have popped up more often)
Thanks for the great video! Big help.
Glad it could help
What did the part cost?
Hello. Can you talk about your tall aluminum valve covers on your Installation? Looks great.
i may have talked about them in an episode where i installed them on the budget build s10 not sure which episode at the moment.
I did this and now my truck idles at over 2000 rpm, how do I fix this?
New IAC
could be a vacuum leak, computer may need relearned, make sure the plug in is in correct and not damaged.
Does it matter what way the connector to IAC valve is plugged in ???? I’m confused now because I unplugged mine and forget what way it went in
It has a singular clip that locks it in place should only go on one way. If the clip is broke off just look for where it was and line it up the the notch sticking up on the sensor
When i put it back on I tightened it too much and the brass broke off and i tried cutting it off with a sawzall but now the inside part is stuck inside the throttle body. Help!
so you still need to un thread the brass inside? well depends on whats all there your going to need to move stuff and make room. brass is soft and you just want to make sure you dont damage the aluminum threads of the throttle body. either use something to grab whats left and twist out or fine something that expands counter clock wise and use that. Now if you are talking about the spring and valve you will just need to unbolt the tbi there is a passage for the idle air and you should be able to get the parts out there
I replace the iac and then I start the truck it was running at high idle , so I took it up the road and drove it hard , drove it back home it seems like running normal idle but the engine light still on and is that how you The computer puts a relearn after replacing the iac ?
I have 1988 Chevy Silverado k1500
@@robertgameworld you may have to rest it Depress the accelerator pedal slightly. Start the engine and run for 5 seconds. Turn the ignition switch to the OFF position for 10 seconds. Restart the engine and check for proper idle operation.
Great video! Thank you!
thanks for watching
Question, would a bad IAC cause my 350tbi to not start when it’s warm? I end up having to hold it to the floor when cranking to get it to go. Cold starts and runs perfectly after it starts.
When its warm it could be or a few other things. Could be it stuck in a spot that is easier to start in the cold.
I have an 89 GMC Sierra 5.7 TBI. I HAVE REPLACED everything electronically as well as the computer and all the fuel components, only idle issue I’m having now is a bad surge at a normal RPM idle. Iac maf tps all have been replaced as well but I did order the cheapos offline but I have multiple I have switched back and forth and still does the same thing I need help getting this gem back on the road safely if anyone has any tips or tricks please and thank you.
check for vacuum leaks, check fuel pressure. has the throttle body been rebuilt?
Could that be causing my truck to stall when getting to a red light but only with my ac running
could be one of many reasons, it should idle up when that pull from the ac is on. So its a good place to look as well as vacuum leaks. or just needing a tune up
@EfurdGarage Thanks man I will check the iac valve. I don't think I have a vacuum leak . But I also have an aftermarket msd distributor so I don't know how long those last. That's another thing I have to check
@@IsaiasMoreno. it should last awhile.
Idle comes down to normal after IAC reset procedure. But when I shut truck off and restart high idle returns. Swapped out IAC and same issue. Is that a bad ECU? Thanks.
check the tps and timing then go from there. could also be a vacuum leak. check those before the ecu
Thanks for the response. Timing is set. Will check TPS. I don't think the TPS would produce this scenario where IAC forgets the relearn after shutting off and restarting. Will research some more though. Thanks
I have a quick question my 92 Chevy has a 350 engine in it and it stays dying when I got a stop was wondering if this would be the problem wanted to make sure before I start spending money
it is a good possibility that it is. may want to check the vacuum to the break booster as well.
How did you fixed it
I have the same problem with
my 95 1500
Mine is idling very high would that also be the issue?
Edit: thank you to this video and the people in the comments. I did fix it after driving it for a while it started giving me the rough idle and bogging thankfully it didn’t stall out I got it fixed and it runs way better thanks guys
When mine failed, my truck started idling about 1000 RPM faster. A new IAC fixed the problem.
yes as James said it is possible it can cause a high idle
My started idling real high too after i changed it
Also boggs out anybody know what can be the issue
@@jonathanrodriguez1880 make sure the plug is in right lol o made that mistake and it ran worse. I fixed the plug then it ran better
So idk if anyone can help but I’ve rebuilt my tbi changed throttle body sensors new jets and new coolant sensors but it still has a hard time idling and it seems like it’s dumping way to much fuel it’ll blow black smoke while it’s trying to idle properly when it over loads and some days it’s just fine but the idle will fluctuate up and down. I’m not sure if it’s fuel pump or something to do with my tbi but I have not changed this sensor yet
Check the fuel while its running. You should habe a nice fine mist out of the injectors. If you have drops of gas or a stream you either have a bad injector or the seal around it is bad allowing the fuel to go around the injector and into the intake. Make sure the regulator is ok. You should have gotten a new one with the rebuild kit make sure its in correctly
@@EfurdGarage I have a fine mist I replace everything on the top side of the tbi but I haven’t looked into the bottom part of the tbi. Idk if I should look into replacing the old one for a new one or convert it to a carburetor. Tbh idk what’s wrong with it. I’ve done a lot of work on it and still have a fuel issue, bogs idles high and sometimes it won’t crank and smells like it’s flooded but the jets mist
Does the connector on the Iac just pull off or is there a special way to remove it
It will have a release button/trigger on it
Is that a bought air cleaner cover or did you make it
I had an old on and modified for sual studs
I want to ask you can high idle speed make the vehicle make it more faster
how do you mean. high idle will make it move a little faster off the brakes but that wont give it anymore power
Does having a bad idle air control valve Cause no power and poor acceleration
It could affect it some, if you are having a rough idle it is very possible, but you could also have another issue
Thanks. I changed mine on 94 1500 pulling a code 35. It is still doing it. Anything else it could be
Pulling same code
Check for vacuum leaks, clean out the inside of the throttle body where it goes, clean or replace pcv, of not those could be bad injectors
Why does my 95 sierra 5.7 go up in revs when i start it up and doesnt go back down to normal revs before changing this? It also wants to go by itself when in drive (faster than normal)?
Check the coolant temp sensor. It may not be working correctly or you habe a vacuum leak
Great video! Thanks for posting. I have an issue with my truck (1991 V10 Blazer TBI): at startup the idle constantly goes up and down, up and down. When I drive it for 10 to 15 minutes the issue goes away. When I shut it off and it sits for 30 minutes the issue comes back. The OBD1 doesn't give me no error codes and the spray mist of the injectors look ok. Could the IAC be the issue? Any input is appreciated!
could be, i would double check the vacuum, tps, and temperature sending unit as well
@@EfurdGarage Why the Temperature Sending Unit? I had replaced it because it was not working with a new one and I think that's when fast idle started. Plus Temp Unit not reading full temp at dash gauge. Any ideas?
@@tedday2008 there are 2 on the tbi on for the gauge and one for helping control how much fuel to dump. I would check the ground that is close to the intake manifold temp sensor as well as the harnesss. And check the harness on the one at the drivers side cylinder head
@@EfurdGarage k
Hi there i have a the same motor i just installed in my 91 Chevy truck. The truck cranks but won't start unless i used starter fluid, what do i have wrong.
you will want to check a few things, if it runs by adding fuel then its a fuel delivery issue which i would start with the pump and filter, then the regulator thats in the throttle body, and injectors. you should be getting a nice even mist from the injectors no drops or streams.
Crank sensor
@@BCGgaming1 the 87-95 tbi does not have a crankshaft sensor
@@EfurdGarage The more you know. I could actually use some advice if you wouldn't mind?
@@BCGgaming1 i can try and help the best i can
Great video. Thanks! It's helpful.
Glad it helped tha ks for watching
How did you know idle control valve was faulty? Did you test it with a meter? Apply voltage to actuate valve ? I’m asking cause I’m seeing people replacing valves by sight or suspicion. I’m looking for a true test to determine if it’s bad or not, but haven’t found anything yet. Good demonstration on replacing one though. Thanks.
This engine had a rough idle with a new tune up. Thats why i did it on this one. Also i have a habit of changing them because alot of people tend to forget about them or dont know they exist. I am sure there is a way to test with a meter
Did you have to reset?
no
Th
Anks
hey man have a question off topic off the video. i also have a tbi 89 k1500.do u think a well tuned quadrajet can deliver better mpg then a tbi?just wanted ur opinion from someone else who also owns both.i have found a well tuned quadrajet can do it.
if i recall in 87 when they switched to tbi from the 86 qjet in the trucks gas mileage dropped 1-2 mpg. driving them i have had better luck with mpg out of the qjet when keeping your foot out of it. also the qjet has more power potential. only time i saw tbi do better on fuel is really cold winters and sitting in traffic alot.
@@EfurdGarage The qjet allows more air flow. this factor gets better mpg. I changed an old '65 Mustang 289 2bbl to an autolite 4bbl by ford and got way better mpg's.....as long as you kept your foot out of it. Foot in.....hang-on!!!!!
Hello. I have a little issue. I am replacing the IAC valve connector and the stock wires are all green while the new one is color coordinated. I was going to cut and splice 1 wire at a time but by the time I got home all 4 wires were cut. How the heck do I figure out what wire goes where or does it even matter? Thanks for the help.
It does, and i am not 100% sure but i found this from an old forum. short A & B together on the ALDL and key-on, engine-off. The IAC should continuously step toward the closed (extended) position. If you do this with the IAC out of the TB the pintle will shoot out and find the most in-acccessable recess in the corner of your garage.
If this test fails by the IAC stepping toward the open (retracted) position, swap two of the alike colored wires. Either the blue/blk with the blue/wht or the green/blk with the green/wht.
If the IAC fails to step at all, you can try different wiring setups until it steps. Then check the direction as above.
The stepper has two coils. One each on a pair of wires. With a DVM can measure the pins until 2 are found that have some resistance (40 ohms? I forget). Put a pair of wires on those pins, and the other pair of wires on the other pins. Then proceed with the direction check.
I just bought a 94 1500 4.3 and the locking tab on the IAC broke off and I can't tell which way the connector goes back on. Anyone have a clue?
There should be a small little tab/nipple/nub sticking out that the tab slides over. The harness although broke should see where it was broke and line up the broke side to the other side
Where did you get that air cleaner?
its just a chrome 14" that i had and drilled it for dual stud
Got a question I hope you can answer. I just changed out my Idle Air Control Valve on my 1990 Full Size Blazer with the same replacement valve you just changed out. I did so because I went on You Tube just last week and asked the Question why my Full Size 1990 Blazer Idles so high and the You Tube Video said that the Idle Air Control Valve was bad and the reason why I replaced it today. Problem is I don't notice any difference. Its been like this a long time but I don't drive my Blazer very much. It only has 65k miles on it believe it or not. I purchased it back in 1995 at 5 years old. It has been idling high probably the last 15-20 years and I had no idea what to do to get it down being it is not a carburetor but throttle body fuel injection and didn't know of any adjustments. Being I didn't touch anything to make it idle fast I thought it was something else causing it. Did I do the right thing by replacing the Idle Air Control Valve for my problem? I thought that maybe the new replacement may have a problem but I just don't know at this point.
I would look into your throttle postion sensor, engine coolant temp sensor. Maybe the regulator which is in the throttle body. If its that low mileage and it has been doing it that long sounds like a faulty part from the factory that never got replaced. Wd40 around the trottle arm make sure its moving properly. Could also be a vaccum leak, You may want to check and or replace the throttlebody to intake gasket. Make sure the bolts holding the throttle body are thight. Make sure the intake bolts are tight. Check the vaccum lines to the map sensor and brake.
What air cleaner do you have? Or is that just a chrome lid?
It is an old aftermarket one like most would use on a carburator. I just mad 2 holes in the lid to use the 2 studs on that throttle body
Good Stuff, picked up a clone of my ride but needs works gonna take both and try and make one good one lol
lol there you go make a good one with 2 thats old school
I have a 91 4.3 with throttle body, the truck idles high when in park and when i put into drive it stalls out. Goes away after a few tries thoufh and it will
Hold in gear. Could this be because of this or the tps.
Could be i would also check the temp sensor on the intake and the o2 sensor
I have 93 gmc yukon 5.7 TBI and when I fire it up in the morning it stalls out so I gotta keep the gas pressed a bit put it in drive real quick then put it back to park and the rpm idle is super low like at 100 or 200 rpms what can cause that?
sounds like it could be a combo of things, but i would check for vacuum leaks first and check the stream out of the injectors
Hey love your channel! 😁🤝 I have a 1987 chevy g20 van 5.7 liter TBI. Lately I’m noticing when I ride a little while , my van becomes hesitant especially when stopping then starting at stop signs. When I just coast and cruise it acts hesitant in and out like it wants to cut off(but doesn’t). And my service light is on.? Where should start?
Thanks You! well if you can get a scanner on it sometimes it works to tell you. I would check the map first and make sure the injectors are a fine mist with no drips. also check all hoses/tubing for vacuum leaks.
@@EfurdGarage Thanks!!!
@@latamorewilliams6443 your welcome
Good video friend I told you that once I washed the housing where this iac valve is screwed in my chevrolet celebrity 1988 2.8 and when reinstalling it I pressed it with the force of my hand and the car feels too unstable, it accelerates a lot when turn it on and when making changes ...
So may that be why there is an air leak and what he mentioned happens to me?
So you have to squeeze something hard, right?
im not to familiar with the 2.8, but yo shouldn't have to squeeze anything hard. It should just screw it with the washer and the harness plug in. make sure you have the washer and the harness is plugged in correctly
I know this video is a bit old but really needing some insight here
1994 wt2500 305tbi
For the last month or so My throttle positioning sensor would act up for the first 5 minutes of driving, throttle would cut out and kick back on for a few minutes while at low throttle highway cruising speed and then it would straighten up and run fine but it was drinking fuel pretty bad so I swapped the tps and it immediately made things 10x worse, it was bucking real bad and was a total pooch unless I had it up above 2k rpms, so I swapped back to the old tps and it’s still bucking and doing the same thing it was with the new tps. Tested the old tps with a multimeter and it has 0.75v at no throttle and slowly increases voltage as I increase throttle like it should and does not seem to have any dead spots throughout the throttle range, so I’m completely stumped, anyone ever experience anything like this?
i would check for vacuum leaks then first, then if you cant find any check fuel pressure, injectors, and distributor.
Ecm flashed code for iac and I swapped it. Now it's worse. And won't start without flooring also got an erroneous code for cts being below threshold 1994 c1500 4.3
Some times it needs a reset. Which you should be able to find online how to do. I didnt need to reset it on this one
@@EfurdGarage I did, that's what's making it run bad. Everyone says run it and it will self adjust, but that's just not the case
@@lancegodbey6450 Did you clean inside of the throttle body? also check the wiring to make sure nothing is damaged and all the connectors are connecting
@@EfurdGarage I just did. All good now. Iac passage was dirty so the plunger wouldn't seal
@@lancegodbey6450 Glad it is fixed for you now
Hello, I have a 1993 GMC G2500 5.7. Were having issues with the IAC we replaced it with a new one, checked wires, vaccume lines, and our obd says the TPS is fine. It starts but wont run due to the IAC being all the way open at 150. Any thoughts? Thank you in advance!
Could be a new faulty iac or bad ground. Have you tried disconnectimg the battery to reset it or turning the key on for 2 seconds off for 10 and repeat and see what happens
@@EfurdGarage We've actually have tried that multiple times, as well as getting the sensor from different places. We're at a loss.
You need to reset the new iac valve. Its in the repair manuel
Did ya ever figure out the problem?
How come you didn't reset the IAC or do u not have to
I didnt have to honestly. I know i see alot about it. But i just pluges and went. Done a couple that way maybe i just have been lucky
I saw a few more of these videos, and they had to reset the idling?
I did not reset anything when doing this. Now if you pull the distributor amd set it then you reset it for zero with a wire but thats about it
@@EfurdGarage okay, i saw other guys connect a wire in 2 ports, of a connector under the dash, so you could set the idle rpm. Already thought why? Install new one and should be alright i thought.
@@Petrolhead350cui yea with the idle air it has always been a plug and go. The wires under the dash are for resting the timing which is for the distributor
What did you use to clean where the iac goes
carb/throttle body cleaner
does the iac have to be re-calibrated?
i have yet to do one that needed re-calibrated. so from my experience no they do not
Good info! 👍
thanks
Whats that collar you have under the air cleaner?
I have a stock collar and an aftermarket air cleaner spacer on top of that
Efurd Garage where did you get the spacer. Never seen one before.
@@jessebenjamin4779 summit racing has a good verity of them. You can get a one piece in the size you need, or spectre makes a set of 3 that you can mix them around to get various heights.
Efurd Garage thanks, i will check it out. Always looking for a way to get more air in there!
@@jessebenjamin4779 with a good raised air cleaner base it basically becomes a velocity stack, i have a video of the specter spacers on my channel
350 tbi on a s10 wow must fly
It was faster then most expected especially on the highway. I never had a good set up to keep it from spinning when i had it at the track. But it could smoke the tires with ease and get over 20 mpg at 65mph.
Was that a AC delco part' ? Because I have a 94 suburban Silverado edition TBI and I want to change it out?
I believe that one was a standard. Its been awhile
www.summitracing.com/parts/smp-ac1/make/chevrolet/model/c1500/year/1994
I thought you had to learn that to the ecm? Or is that not true
No the old ecm really didnt learn. Only thing om these older tbi was resting timing with the brown wire
I have a 91 Sierra c1500 with the same engine and when I replaced the IAC the truck ran so bad almost like it had a serious vacuum leak. When I asked around I was told that upon replacing the IAC that there were steps to take after installing it. Any recommendations? Thanks in advance
You could try disconnecting the battery. I didnt have to take extra steps but you may need to take it out and clean out the hole and put it back in
Curious, why would you not be able to throw some carb cleaner on the old IAC?
You can do that, which is what I'd do first, but sometimes they're just flat worn out.
like sean said you can, but this one has been in there since 94 so i would rather just replace and go.
Efurd Garage In the video you said you heard not to apply cleaner to the actual IAC that’s why I was asking cause I saw other videos were they said you could. Mines a 91 caprice seems I just cleaned it but it seems old I’m just gonna replace it with a new one along with the map sensor. Seems to be running better since I cleaned everything with carb cleaner tho.
@@str8profit81 yea i have heard not to. But i have yet to ever try and forgot that honestly. I dont know anyone personally that has cleaned it like that so i dont know any short or long term effects
Out of all these TBI IAC changes, none talk about the IAC reset procedures.
they adjust themselves thats how they work.
@@EfurdGarage there's a reset procedure in the factory service manual and you are not supposed to move the plunger at all.
hell yea brother!!!
Good old TBI's lol
If he can hold a wrench he can do it....
thank you
I’m guessing u didn’t pay for that can 🤣🤣🤣
i did, they were chap back then
Good Information but your loud music stinks.
Thanks, that was an older video and the opening has been chanced since
It is a little much on the "music", but good instructive video.
you mean the 220 TBI , not a 350 TBI....350 CID.
yes i mean 350 tbi, 350 with throttle body injected. not a 350 with a carburetor, and not a 350 tp,i 350 with tune port injected. But a 350 cubic inch displacement that is throttle body injected i am referring to the engine as a whole , as it is my setup.
@@EfurdGarage just poking fun at ya!!! i know what ya ment
@@jotegg1276 😆 honestly.... You would be surprised the people.... Well you beem on the Internet im sure you seen them i really probably dont have to explain
@@EfurdGarage I got into with some dummy who insisted that gm did not make a 1994 Blazer 1500 Silverado model. There's no such vehicle! Lmao
Still figuring out my issue with idle.
Why don't you use throttle body cleaner etc on an IAC?
some of those cleaners are harsh and can hurt the rubber and seals inside them.
My 92. 350 it starts then it spuders for a few seconds then it goes to ideling perfect
could be a slow iac, or even have dirt in the hole. weak fuel pump, worn out tps, or vacuum leak