Jeep Wrangler YJ - How to test the MAP sensor.
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- Опубліковано 8 вер 2024
- Jeep Wrangler YJ - How to test the MAP sensor.
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And thank you for all your knowledge you've really helped me out with a couple issues on my YJ, thanks!
Well, I guess I need to thank you...I think you just helped me pinpoint a issue with my Jeep. the center wire has 4.5vdc at power on, but when teh engine starts it drops to about 1.6vdc - what concerns me is that when I rev up the engine slowly i do not see a steady increase in volts - at about 3k rpm its still about 1.7 vdc
This video is --- over the top ,there is no excuse for anyone to not understand an be able to do the checks. I have watched his other videos ,go ahead an subscribe an like his videos, you will eventually need to look at them all . ITS the way it is.
Ура, наконец то в это видео появился титры на русском языке (хоть и автоматические) теперь у меня появился шанс привести в порядок мой yj. А то заводится крайне неохотно. Одну проблему я нашёл. Это термодатчик на термостате. Буду дальше изучать эти видео по мере появления русских субтитров. Спасибо автору за работу.
Guess will be watching your videos on how to test and fix things in YJ 1992
alright thanks power addicts I think I found the problem though. I pulled the vacuum on my map sensor and ever since it has run great and has stopped dying on me
Thanks! Easy enough!
You are welcome. Glad it helped!
Your style and manner of explination is outstanding. ( plus it really helps u know your shit) Your web page sounds great and will be the gospal source. Can't wait. Thanks for the great solutions. I'm an old 60s dealership mechanic ( in my 70s) and don't speak beep beep buzzz. Haha
Thank you for your videos they helped me out immensely!!
Great video, I just tested the MAP sensor and the reading goes up instead of down while applying the vacuum pressure. I guess is time to change the MAP sensor.
***** Sounds like a new sensor is in order to me. That's a new one on me. I've seen them not read at all. Erratic voltage as it tests. But not voltage raising as vacuum is applied. Well . see new things all the time if pay attention. Glad you liked my video. Thanks for taking the time to leave a comment! Have a great day!
Thanks for all your help, im sure now i can find the problem on my jeep wrangler
You are welcome! Glad the video helped. Thanks for taking the time to drop in a great comment! Have a great day!
Like the way you explain things.
Hi , do you know where the vacuum line is coming from I recently bought a YJ and theirs no vacuum line connected to the map sensor and you seem to be the only one thus far that has a video closely related to what im struggling with
Thank you for this and so many other videos you have done.
You are welcome! Glad you enjoy the videos!
Eggsellent video
Glad you enjoyed the video!! Thanks for dropping in!!
Thank you!
You're welcome!
If my input is low. Do you recommend putting the wiring harness apart to find a bad wire. Or is there anything i should do before I take on that job
Your Videos are Golden!! Thanks!!
You are welcome! And, thank you very much!!
Thanks Bro. Awesome to know.
+Paul Roberts Youre welcome and thanks for the subscribe!! Have a great day!!
Thanks i can do this you shared some really good information.
You are welcome! Im happy the information helps you! Thanks for taking the time to leave a great comment! Have a great day!
Nice and simple...thanks again! loving the videos!
Glad you liked it! Thanks for checking out the video and taking the time to leave a great comment! Have a great day!
It would have been nice if you showed the setting on the meter But thanks for the Video
Set it on DC voltage, that is what cars run on. Look up what the symbols mean on multi-meters.
@@Poweraddicts I know where the DC side of the meter is , but your scale looked like it was set below 20 on the DC side i was just wondering if that was the case because im not sure the 20 would read 5 votes that was the only reason i asked
Great tutorial !
Straight forward to the point
Keep it up !!!!!
Thanks, glad you like it and hope it helps! Thanks for checking out the video and taking the time to leave a comment! Have a great day!
heyho, quick question, if i have missfires and stumbles while driving, unplug the vac line on the map and it runs like "perfection" it seems like the map is broken isnt it?
Just A quick question my RPM Guage on my 91 Wrangler 4.0 does not work when I bought. Can it be fixed? If so..... how can I do that. You help would be very much needed. Very Good videos thanks for posting your knowledge.
Old Wranglers are bad for dirty corroded contacts. Pull is out and clean the wiring contacts. You can use vinegar or hot sauce works well.
Great video, brother! Thanks!
You're welcome! Glad you enjoyed it!!
your stuff is right on my MAP is 5.25 going in, but the signal is 4.31, plus the ground shows a little, juice, I think I got a bad Map sensor plus the high speed WOT does not work.
Very well could be. Also if you are having issues at WOT, may need to check the TPS. I have a vid for that also. Here ya go: ua-cam.com/video/URNYaGXM_uQ/v-deo.html
Where does the plug on the left side go?
I have a 89 keep wrangler yj with a 2.5. Runs good until it warms up and then just stalls out. I've put a map sensor o2 sensor crank sensor ignition coil new plugs new wires new cap new injector new throttle sensor new thermostat new fuel pump I'm lost do you have any suggestions for me
90 wrangler yj 2.5. I'm having similar issue & have done everything you've done including new catalytic converter/muffler. I am at a lost. Starts off running great. Once the engine reaches a certain temp and I turn it off. Problem occurs when I try turning back on after being off 5min or longer the engine will sputter, sometime backfire, as I have the pedal completely down hoping it gets enough gas until it begins to runs. Once it starts to run it still sputter for a little bit more until it seems to clear itself up.
Frustrated... Please advise if you resolve your issue & how. Hoping it may be the same. Thank you in advance.
Did you test the temperature sensors,... There is a temperature sensor for the coolant. That is usually locked on or near the thermostat housing.
And there is also a air temperature sensor that is either in the intake manifold or the air cleaner/ filter assembly.
Both of those temperature sensors have to do with controlling the fuel injection system.
Great video but when I take my hose off the MAP my jeep cuts out. I have a rich mix shooting black smoke out the exhaust. Was told to check the MAP. Oddly when the MAP wasn't plugged in but the hose was connected, it ran and sounded like it used to. And then stalls. Soon as I plug the connector in,it runs like a misfiring dog and back to black smoke. Should the engine still run if the hose is removed??
Just tested the Center wire ,
Wire B. With everything connected, with the Engine running at Idle. That wire terminal should have between
1, and 2, volts,. Probably closer to. 1. Or 1.5 .
If the reading is higher than 2 . volts with the engine idling,
Then the MAP Sensor. Is faulty, or the Vacuum hose going to it may be plugged up or leaking.
Thanks. Now what’s the best way to test that vacuum on the other end is good ?
also the rumor is that that plug I asked about is for a under the hood light? not so sure myself though
My jeep was running fine then all of a sudden it sputters an pops an won’t take the gas ? I just changed the tps .. same issue ? Crank position sensor ? Or cam sensor ?
I have a 1990 wrangler YJ 4.0 crank no start. If I introduce a short shot of starting fluid it starts and runs perfectly. Just a note it has a new fuel tank, and a new fuel pump recently installed but I still have the same situation. What do you think?
Hey I have a 88 jeep yj with an inline 6. I just added a new 2 barrel carb and fuel filter.. the problem I'm having is when I get on the freeway eventime it dies and acts like I'm out-of gas. Even though the tank is full.
Sounds like your fuel line may be getting too hot and vapor locking. On a carb rig, I personally don't care for the manual fuel pump. I always run electric pumps. They are more forgiving of heat and easier to change on the side of the road if needed.
Can you do a videoshowing how to test the temp sensor thats screwed into the back of the block? Oh, and great video, I need to check mine.
Thanks, glad you like the video. Hope it helps! I'd have to find the temp to resistance chart. Honestly, that sensor is so inexpensive that if I took it out, Id go ahead and put a new one in anyway. Have a great day!
I hope you see this! That ground wire on the firewall, right of the map censor. Where does the other end go??
If you are referring to the all metal Ground Strap, one end is bolted to the Firewall, and the other end should just be bolted to the Engine, Either to the a clear paint free place on the Engine Block, or a Clean Paint Free place on the Intake manifold.
Couple questions..Is your Jeep the 4 Cylinder? Noticed for me was difficult to catch your three readings for the vacuum (in the video sounds like you said 10 and go 10 more and than 17? Hard to also read the gage. Was your three gage readings 5, 10 and 17 in Hg Vaccium?
Your video is outstanding for a YJ fan. In the Haynes, says nothing. Even in the Chrysler service manual, really has no figures on vaccium.
Ever seen a spread chart for the map like they show for a temperature sensor or throttle position sensors show?
Thanks for all the help. Nearly 10K on my rebuild. Have a fast idle issue. Sure it's probably carbon on throttle butterfly or IAC.
I have a 1990 Jeep wrangler and it throws out black smoke excessively from the muffler. Would you happen to know the issue?
what is the grey and black female ended plug to the left of the map sensor? what does that go to?
Thanks that was great
Glad you liked it! Thanks for dropping in and taking the time to leave a comment! Have a great day!!
Excellent!
Good video. I have a 1989 islander with the carbureted 4.2L but can’t find anything that looks like a MAP sensor. Do you know if it has one?
On a carb vehicle they don't have a map sensor. The fuel adjustment is done through a screw on the carb, along with the idle screw.
I've been having an issue with my 91 4.0l, It starts after the first crank when its cold but after its up to temp it will crank forever before it starts and has a high idle that settles after about 20 seconds and idles rough??? I have to let it sit for a few seconds with the ignition on and then it wont crank as much but still cranks alot before it starts and only when its at temp, i have checked the fuel pressure and its locked in a 30psi, the pressure does not drop off which is why I'm stumped right now... Do you have any suggestions on what I should be looking for!
Hey, Great video! I just did the test on my 1990 Bronco and i got 0 volts in one wire and 3 in another. Where downstream should i check to fix this problem?
Sean Rafferty Thanks :-) Best suggestion I can make is find the pin out schematics for the ECU. Then test the wire coming from the ECU pin that feeds voltage to the MAP. If you have low voltage there, could possibly be a bad ECU. If voltage is good from the ECU pin, then you have voltage drop going to the MAP. Also make sure your ground is solid for the MAP. A "not so solid" ground can cause a voltage drop also. Hope that helps. Thanks for dropping by and checking out my video. Good luck and have a great day!
my 92 giving fumes. so the MAP (manifold absolute pressure) I got ta clean
If you got fumes, I'd change the O2 sensor as well. There is always the possibility of a fuel leak, the vent or gas fill hose going to the fuel tank.
also I have a 4.0 liter 95 yj manual transmission can you help me with a problem? I am getting code 36 from the onboard code reader and no one knows what it is? its a wastegate open or shorted for the supercharged models but mine is not supercharged. for the models not supercharged it is called the air switch solenoid. what the heck is this and where is it located? thanks
What if you get 5 volts and .99 on the second wire. What do I change.
Could that be the reason I loose rpm when I go up an incline and lose speed.
I'm getting P1296 after I replaced the IAC & TPS. Cleaned the throttle body, changed the spark plugs and replaced a broken vacuum boot. Stalls at low speed, stops and deceleration. If I replace the MAP and still stalls, what's next??
I would test the fuel pressure also, to check for proper pressure at idle,
Had a similar issue on a van a couple years ago and we discovered it had a faulty fuel pressure regulator.
Question: if I replace the MAP and Oxygen sensor, due I have to do anything with the computer? Or will it auto recognize the new sensors? And will this stop the gas smell by the tail pipe?
Disconnect the battery for at least 30 seconds and it will recognize the new sensors. The computer will learn to interpret the new sensors as you drive around. It may or may not fix your gas smell depending on the original cause. Check to make sure your fuel pressure is correct. 30 psi at normal idle, 40 psi with the vacuum hose disconnected from the fuel pressure regulator (at idle).
Hey great video! It was really helpful, I've been trying to determine my running lean issue, I have pretty much narrowed it down to either the map sensor of possibly the ecu. I have just checked my readings, at 0 in Hg I am registering 4.05 v. At 5in Hg I am at 3.14 v. At 10in Hg I am at 2.27 v and at 20in Hg I am at .49 v. My 5v reference and ground both check out. However online I found I should read 4.7 v at 0 Hg. 3.9v at 5v Hg. 3.0v at 10in Hg, and 1.1v at 20in hg. Do map sensors get weak? Do you by chance know your voltage readings?
+B Sanchez Glad you liked the video! :-) A MAP can read a bit out of spec and run fine, just not efficient. I have the Chrysler Shop manual for thes XJs & YJs. it doesnt even specify exact voltages. Just that with 0" it needs tobe very close to 5 volts. It more about the voltage sweep being steady as vacuum is applied. I watched my video again. At 0" I was @4.85 volts. Then at 17" I was at 1.7 volts and had steady voltage all the way through. Your 0" reading is too low for my taste. I thing the lowest it should go is around 4.6 volts or somewhere around there favoring the higher side. In short .. I's swap that MAP. www.fixjeeps.com/map-sensor.html .. here is the webpage that goes with that video if it will help you any. Thanks for dropping in! Hope this helps. Have a great day!!
possibly a silly question, if my input voltage and its 5 volts, and off the sensor is 1.5 volts with the key on does that mean the sensor is bad?
Yes. That's too much voltage loss at zero vacuum. Swap the sensor with a new one.
We have fuel smell coming out of exhaust did you ever do a video on the regulators. 2.5 94 yj. Thanks.
Yep, I did a video on testing fuel pressure. Your problem may be a bad O2 sensor.
Got a pressure tester and it maxed out and then it turned out the return line was plugged inside the tank. Thanks
Hi, can you help me with reverse lights not working on a Yj 94.....???? Thanks
I just put this on the to-do list of videos to make. Make sure you are subscribed and click the bell so you will be notified of videos released.
my 88 cherokee is struggling to hold 55 mph.to me it acts like the advance and right amount of fuel is not being delivered. -- back story the fuel from the tank to the injectors all checks out.pump good, filter changed, and regulator changed out.
wiring--did the bulkhead connector eliminate and repaired 4 grounds as per Cruiser 54's tips. did all the ground cleaning and refreshing. new battery cables pos and neg. replaced the IAC and the TPS. i am slowly gaining. it shifts up and down thru all gears fine. had good power one month, then crap the next. only thing left is CPS or the MAP sensor. open to suggestions here. cat is clear and not clogged. exhaust is not bent or obstructed
also the EGR is dis abled and not leaking. hoses plugged for now till i get full functioning back. also replaced all my vac harnesses on engine with left and right from NAPA
You say the fuel pump is good. What was the pressure?
35/34? at idle and 39/40 when you open it up off idle.
i also changed out my fuel tank due to rust. my old one was clean inside and the rubber hose on the pump and sender was leaking. i replaced it and new clamps
Rust in the tank. Possible you could have rust in the lines cutting back on the volume of fuel getting through. You can have good pressure at idle and just off idle. But if you have blockage in the lines, the injectors will start to run out of fuel and pressure once you get up to speed.
subscribed too
I've a sqeal when giving throttle just replaced tps got map on order ??? Any help your videos are great
Jason Thomas Glad you like the videos and thanks for great comment! It runs fine other than a squeal when giving throttle? TPS or MAP isnt going to squeal when giving throttle. First thing I think of is the fan belt slipping. Hope that helps ..
Power Addicts - FixJeeps.com - Jeep, car and motorcycle tips
What did u put multimeter on
I have a question for you I've been seeing where they are people say a s10 steering column will fit in yj do you now anything about this
It probably will seeing as how Jeep used Chevy steering column around that year in the Cherokee's.
U never mentioned what u put your setting on multimeter.
What if my input voltage is 5.02 and reference voltage is 4.46? Is that too low?
+AssGrabber B
It on the low side of the tolerance in my opinion. But ultimately it will come down to if the engine is running correctly. I ran with mine outta range for a long time. Did it make it run bad??? Not really. But once I changed it I did notice that the throttle response was better. So honestly, if it's running OK, it's up to you or your pocket as to whether you wanna change it. Thanks for dropping by! Have a great day and a Happy New Years!
My 88 yj does not have a map sensor or ecu lol.....nice video though.
1991 was the first year for fuel Injection. So .. nope yours would not have that stuff. Glad you like the vid! Have a great day!
My 88 XJ has it
I am have a 99 Tj 4.0... NO CHECK ENGINE LIGHT it has a rough idle and SOMETIMES it idles up (mostly in park) to 15 - 2000 RPMs it feels like it also misses. sometimes and idk if related but the fuel gauge drops to no gas then comes back up.... i took it to a shop they said it was the PCM/ECU. got a reman plug and play issue remains
I have Cleaned throttle body and IAC new plugs wires PCM checked for vacuum leak (break clean and smoke test)
PLEASE HELP!!!!!!
Thomas Bowe I have seen on mine that there can be issues with a sensor and it not light the "Check Engine Light". Havent tried this on the TJs but here it a video on how to make the ECU tell you if its storing codes but not lighting the dash light: ua-cam.com/video/KRuxSgkOyig/v-deo.html. I need to try this trick on my friends, his is a 2000 model. After everything you have done, I would try next is testing for a vacuum leak somewhere. Get a can of starting fluid, with the engine running at idle, spray along your vacuum lines. If there is a leak, the engine will rev up for a moment and then drop back to normal. Also, comes to mind also that possibly the IAC may be occasionally not fully closing. Also check the TPS, mine would erratically high idle (but only go up a few hundred RPMS) ua-cam.com/video/URNYaGXM_uQ/v-deo.html ... ua-cam.com/video/0wrrojhJ4XY/v-deo.html . On the YJs the fuel gauge circuit is its own circuit. I haven't had the opportunity to have to trace a fuel gauge circuit on the TJs. Here is the video on how I addressed the YJ fuel gauge: ua-cam.com/video/6i9X2agOEYs/v-deo.html . Let me know what you find out. Thanks
Power Addicts I did a smoke test and a cab cleaner test... The motor revs up when it wants to and kinda feels like a misfire and sometime runs ok... also omly got 225 miles out of a tank.. is that normal??
Thomas Bowe You could have either a 15 gallon or 20 gallon tank. Which one you got? If its a 15 gallon it will not be too far off. Also depends on what gear you have in the diffs .. automatic or manual? Mine is a 4.0 5-speed with 3.07 gears rolling on 31 x 10.5 tires, it get about 18 miles per gallon if I baby it. My sisters gets about 12- 14 but hers is a 4 cyl. Jeeps Wranglers are not known for good mileage. If yours is a 15 gallon getting 225 per tank .. thats about 15 miles per gallon. If its a 20 gallon .. you are getting about 11 MPG, that would be abnormal. As for the running issues. I'd suspect that IAC is erratically sticking. Problem with that is there is no consistent way of testing that if it's an occasional thing. Run for trouble codes immediately after misfires. The ECU doesn't always light the trouble light, but it can store a code a period of time afterwards. My Jeep the first time I ran a code test it told me that MAP was bad... never had a light. The TPS on mine was acting up, it never threw a code or even had one in the ECU.
my 2001 tj on 31's and 373 gears got 280 miles a tank at 75 mph. the coil packs can have intermittent misfires you may need a new coil rail for it.
What happens if the central connector gives me 4 volts?
Ig the center connector has 4 volts when the engine is idling,
Then the MAP Sensor is faulty,
Or the Vacuum hose going to the sensor could be plugged up or leaking/ broken.
DOES MY 1988 JEEP WRANGLER 4.2 CABURATED MOTOR HAVE A MAP SENSOR
Nope .. no MAP sensor on a carb'ed engine. Have a great day!
@@Poweraddicts really? And yet rockauto sold me one. I was just ordering multiple sensors to change out on an old jeep and that was one of them.
@@oilersman99 then you don't have a carburetor jeep. It's possible you have a TBI converted 4.2.
Went out to check my MAP sensor to see if it was my issue, ill be damned if the vac hose wasn't even connected.
That will cause an issue no doubt :-). Glad it was an easy fix.
Great video. What does the MAP sensor do?
Thanks, glad you like the video!! The MAP means "Manifold Absolute Pressure". In non-geeky terms that means it measures the vacuum signal in the intake and converts that "pressure reading" into a voltage signal. Then it sends that voltage signal to the PCM (engine computer). The computer then adjusts the ignition timing and fuel/air injector mixture based off that reading the MAP sensor sends to the PCM. Hope that helps :-) Have a great day!!
could that cause a gas smell at the rear of the Jeep?
My 99 idels at 2k what could it be
Vacuum leaks, fast idle solenoid, throttle cable sticking, throttle shaft sticking .. there are several things that can cause that.
I hope you can help with this issue. I have a 1993 YJ 4.0 5 speed. I have replaced the fuel pump, filter, pressure regulator, cap, rotor, plugs and wires. Sputters occasionally with no pattern. Was doing it since I bought it a year ago and still after I replaced the parts mentioned above. I have not checked the MAP sensor yet. Think it could be that or just a Jeep thing??
InjunOne MAP can cause that. Bad vacuum lines possible. TPS can cause erratic flat spots or sputers. Check out this video: ua-cam.com/video/KRuxSgkOyig/v-deo.html . Some issues will not light up the check engine light but will store a code. This is how to get the Jeep to cough up the trouble codes if it has any stored. If it doesn't at the time you try. The next time it sputters try running the code asap afterwards. Mine was acting up one time .. it was off and on that it would. Turned out to be a bad MAP ... so it;'s possible.
Thanks, TPS was also replaced. Thank you for all your help!!
InjunOne Glad to help! Let me know what you find.
Once again u never showed what u set your meter at.
Not very helpful if people dont know where to set their meter at.
2:52 black wire on battery, red to check dc voltage, set multiplemeter on DCV
Your style and manner of explination is outstanding. ( plus it really helps u know your shit) Your web page sounds great and will be the gospal source. Can't wait. Thanks for the great solutions. I'm an old 60s dealership mechanic ( in my 70s) and don't speak beep beep buzzz. Haha