Fix a Car That Runs Rough But No Engine Light - MUST WATCH
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- Опубліковано 11 жов 2020
- In this video I will go over how you can go about fixing an engine is running poorly yet there are no check engine lights or no codes stored when you use your OBD II scanner. Be it a misfire, bad Oxygen Sensor, Faulty fuel injectors, clogged air filter, exhaust leak pre B1S1 oxygen sensor, stuck open evap purge solenoid, a bad MAP or Mass Air Flow Sensor.. whatever it maybe you can start by watching this video to the end.
Here are links to products which were used in this video:
Entry Level Scanner: amzn.to/2mjf7YS
Pro Series Scanner: amzn.to/2bXGDp4
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Disclaimer:
Due to factors beyond the control of Ratchets and Wrenches, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. Ratchets and Wrenches assumes no liability for any property or personal damage that may arise from doing a repair on your vehicle after watching any of my repair video's. Due to factors beyond the control of Ratchets and Wrenches, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Again Any injury, damage or loss that may result from improper use of tools, equipment, or the information contained in this video is the sole responsibility of the user and not Ratchets and Wrenches. - Авто та транспорт
Here are links to products which were used in this video:
Entry Level Scanner: amzn.to/2mjf7YS
Pro Series Scanner: amzn.to/2bXGDp4
Good morning, how is it possible to get in contact with you?
We should do a video together. I live here in Chula Vista. I have a Jeep Liberty that we can do a video with
D
My code is ford p0132 and p2197 lean stuck high voltage.
Air leak? Or bad 02?
When I start cold and drive it randomly will stutter and randomly refuse to accelerate but after its good and hot runs fine. Even when cold if a floor the pedal it takes off no fuel dump issues. I can't find air leak but my filter was dirty and the casket needs to be replaced. Of course its old 2005 123k miles
When ever I attempt to DIY I go from a rich condition to a poor condition
Hahah, awesome! That's how I was before I learned how to actually test things and not use my parts cannon.
@@thalegacy6 hello, my truck starts and runs well but after 20 mins running hot the engine runs really really rough and will not drive, can’t figure out what’s causing it.
😂😂
@@ChrisRobba so during open loop, I I would check O2’s , but it could be Many things. Have you figured it out yet? Do you lose coolant?
@@mayken6661 to be honest I have given up for the time being I tried working on it for about a month doing the easier things first now I’m just letting it sit in the driveway. A lot of people say fuel pump but haven’t replaced or tested fuel pressure. Don’t know how to check sensors I’ll look it up, no coolant issues, too me it seems like it’s struggling to maintain correct air fuel mixture but what’s thrown me off is that it takes 20 mins to start doing that. Symptoms are shaking of Engine, poor to no acceleration, stalling. Louder, and all around having a heart attack. Seems like a overheating engine from loss of coolant or oil but it’s not that.
For a ten minute video, that was actually very comprehensive. Many people could learn a lot from this.
For years, every time I have had a problem with my cars your videos have always come to the rescue! Thank you! You videos are well produced and have excellent content. Thank you for mentoring me through my DIY adventures all these years!!!!
HUGE THANKS! Got a 03' S10 4.3 Vortec that's been pulsing when warmed up. Couldn't figure out the problem (no codes) and then (after watching this and using a Autel scanner w/live feed AND NOW UNDERSTANDING what the numbers meant) decided to check the pre-O2 sensor and the pipes leading up to the engine and FOUND A SMALL LEAK. Fixed leak and replaced exhaust seals (donuts) - and FIXED ENGINE! Truck has NEVER ran so smooth and SO DANG QUIET! HUGE THANK YOU - been trying to get this sucka back to the way it used to run when I first bought it back in 03' . Might have took 17 years but DANG!!!!!!!!!!! THANK YOU - got a WHOLE NEW APPRECIATION for people that TEACH!!!
(In Professor Farnsworth's voice) "Good news, everyone! I've come up with a simple explanation for air/fuel ratios! Let me show you four real-time graphs at the same time so your heads explode!" Serious, very concise explanation of what it all means.
Your vids have a great average Joe vibe to them. You're helping us all out. Thanks! I would love to see more electrical diagnostics/repairs if you're into that stuff
More humble than average I think. Humble Joe vibe
You have intelligent, actual content with excellent delivery. Clearly you are highly educated about your industry. Subscribed today and I look forward to playing all your videos
The amount of uploads since you got back is insane !
Wow thank you. I ran my engine on idle and the LTFT was 10%. I sprayed some soap water on the hoses and found the vacuum leak. You saved my car bro. Thanks.
Glad it helped
Your videos are the most thorough and most clearly explained I’ve seen. Thanks for sharing your vast knowledge.
Glad you're back on the scene... great video.
Remind me of the homie in Wyoming 👊Over the years you have been making my backwards introduction to doing it yourself a lot easier with these common sense videos with some slick west coast humor! Hope your avacados farm is producing for you and family's well. Happy new year looking forward to any types of vids you decide to make whether about cars or not keep kicking homeboy!
Always appreciate your videos. Practical and to the point, while giving enough technical background to satisfy most curious minds.
Thanks, I learned about fuel trims today and my scanner has live data capability.
Also, lol at Beavis and Butthead.
Thanks,having this exact issue but worse when stone cold/just after starting.Now i can look at the scanner data with some knowledge. Keep up the great videos!
Great video on rough idle, long and short term fuel trims
Thanks for sharing 👍 😊
Really enjoy his videos,super informative! Glad to see you also had my red autel scanner!
14.7 avocados to 1 part lemon juice. heck yeah.
Guaaack
FREE guack!
You're definitely running rich
Very Good. I've been a subscriber for years and your videos are getting better and better. Greetings from British Columbia, Canada!
Thanks so much for the info!! I think this may be the problem with my 2010 Chrysler Sebring. It has a rough start, and sometimes a long start. Runs and rides very smooth, but sometimes idles a little rough. I have an OBD2 reader with the Torque app. I'll have to see if I can check those things you mentioned with it.
Excellent explanation, thank you.
Whenever I have rough idle or running conditions without any codes my natural instinct is to check the entire intake/clamps,connections, sensors for the intake and most importantly check that throttle body and give it a nice clean. Any air that is escaping the inlet pipes will trip the vehicle out
Informative, useful and straightforward. Thank you!
Gracias por tu tiempo que pones en todos tus videos ..
👋from Brazil, really like your videos( need a beater car when arriving Canada in a few months).
Loving your vids in Australia mate👍
Long Term is the window of time the adaptive memory dictates the fuel trim, Short Term is live data calculating to learn the parameters for the adaptive memory to update the Long Term. The O2 sensor signals lean below .45 volts & rich above .45. The Engine Controller only cares about that threshold & uses that to determine fuel trim. .. in other words the computer calculates the % of time that the O2 sensor is past the threshold of .45 volts & does that each time the threshold is crossed.
Thanks that's the best graphic explanation I've seen showing how the STFT transfers over to the LTFT when the oxygen cell starts to oscillate again. One question: do the downstream oxygen cells oscillate as well or do they show a steady reading when the engine is in the stoichiometric zone and operating normally? Long time subscriber, thanks for all the great info.
Thank you. This is the video I've been waiting for I have this problem. No engine light no codes truck stalls, same exact motor as yours so this works out great for me thank you again. Have a blessed day
Glad it helped
What was it
This was informative. Thanks!
Esta bien muchacho, ole'! You gonna more to Tennessee like Scotty? You guys are performing a valuable public service. Thanks!
Thank you!!!! I’ve been trying like hell to find info one where to start since my transmission is hard shifting especially before engine fully warms up, but there are no codes. And it’s driving me insane because each hard shift is damaging the parts inside the transmission little by little. So awesome video, very useful ✊🏻
Did you ever get a torque converter code?
Check throttle position sensor. He has a good video on how to check that. That can cause hard shifts sometimes.
You are a cool dude man..thanks for your teachings bud!
Extremely informative and explained well. Thank you!
Thank you for that! Great video and very helpful!
Thanks, very well explained!
Thanks!
I've been looking for a good explanation of fuel trims? I think I understand it now!
Lol before OBDIi and techs had to actually figure out what is wrong with car. Great upload and in knowledge transfer
Yup. A few years ago, my 74 Chevy truck was running rough. It would intermittently run like crap making me think it was an electrical issue, but every time I'd pull a hard acceleration, it would dog down and nearly die making me think it was a fuel issue, possibly a bad accelerator pump. Confused the hell outta me before I realized that I had two separate issues. It was both electrical and fuel related. My points were fried and the fuel filter was clogged. Duh.
When was the last time I did a tuneup? I went to that new Napa in the next town over, but I haven't been down that road in...
Oops.
Off I go to the parts house. Told the young kid behind the counter what the symptoms were and he said he could pull codes and tell me for sure. I told him it was a 74 Chevy and he says, "No problem" and grabs a box of adapters for his scan tool. I was gonna let him hunt around under the dash for a while, but his boss stopped him before he made it to the door.
As I'm walking out with a bag o' parts, I realized that I had no idea where my tube of Malory went to. So I turn around and ask the kid where the points lube is.
He just stares at me. "Points lube?"
"Yeah," I say, "Y'know, distributor cam lube?"
He scratches his head and leads me down an isle. "Hmm, we've got moly lube..."
"No, points lube. Silicon based distributor cam lube. It's like dialectic grease except it's made not to get slung off the distributor shaft. It goes between the points and the distributor cam." I'm not sure this kid has ever even _seen_ a distributor.
After confusing the kid for another few minutes, his boss saves him again.
"Yup. I know what you're talking about, but we haven't carried that for a while now. I only sell a set of points once every month or two."
I had to travel 150 miles before I found a town that had any. Had to go to a store that specializes in classic cars. This old timer comes out and I tell him what I want.
"Oh, we don't keep that on the shelves anymore."
He goes behind the counter, grabs this dusty old cardboard box, and pulls out a tube. It wasn't Malory, but that's okay. I think they went out of business about 10 or 20 years back. $8 later and I'm heading home to do a long overdue tuneup to my truck.
I weep for the next generation.
They still do, because even OBD II can be fooled by other problems. Many times the code can't be fixed by firing the Parts Cannon; you need to figure out what's causing the code.
@@markh.6687 understood but before OBDII you had to be on your game to diagnose with minimal comebacks and still be on the gravy train.
@@maingun07 To be fair, we deal with the modern just as you did. Old cars are like old computers - there are a few specialists with the knowledge, but the plethora of new machines means most are familiar with what is in active service.
Interesting story, tho.
@@TheRebuilt1 Yes you did; you still do today. Lots of SMA work starts with a botched job by "pros" that couldn't or wouldn't be on their game.
I'm impressed by your knowledge
Got a good one for you. I have a 2001 Ford Explorer Sport trac. Mfg date is the first (there were two slightly different models of the 4.0 SOHC is what i've heard, don't know how factual that is).
A bit of history - it's necessary and i'm hoping better help you with your video content idea. -Shout out to Joseph Harlow if you do it because of this comment. I don't know why but in my opinion. It would be cool to know something I added fueled your creation. haha ( everything obviously still your intellectual property )
So, 137,000 miles. I bought it at 133,000. First issues were valve covers leaking, had that fixed by professional mechanic. In addition to some suspension maintenance/repairs. I'll stick to engine though for this just to stay focused on the actual problem and difficulty locating the cause/remediating it.
The list of engine repairs below are notated in order of symptom - repair
symptom: visual inspection determined leaking coolant around the thermo housing -
repair: replaced thermo housing. .
NOTE: With this and anything i've personally repaired. Has been an absolute nightmare. I believe because it's just never had anything replaced since driving off the lot from original purchase. Long story short, I broke a bolt trying to remove the leaking thermo housing. Took almost a full week in freezing weather to get the fu***** thing out and re-tap the hole. I was able to get a nut and bolt to secure well enough to pass a pressure test.
symptom: rough idle at stop and heavy vibrations at low rpm/speeds with slight jerking and whining noises from power steering pump.
repair : replaced power steering pump but kept the same pulley.
symptom: squeaky belt and/or pulley
repair: replaced with a noise reduction/higher performance belt (didn't believe it myself until i experienced it, the more expensive belts DO make a tremendous difference)
symptom: still rough idle, getting worse and to the point of almost completely stalled engine if stopped and/or in park/reverse. In addition to low speeds/rpms. If in Neutral and/or driving higher speeds/rpms. The sputtering or hesitation would not be noticeable. Though if i press that accelerator down harder ( not flooring but like if i was to try and pass someone on a 75Mph limit HW) I hear a sort of clacking sound. . .similar to what an exhaust leak would sound like if a manifold would come lose on the block. Like on some of the Dodge rams. Only when accelerating harder than normal though. Normal acceleration doesn't do it.
Attempted repairs without resolving:
Replaced all spark plugs, spark plug cables, PCV Valve, IAC, O2 sensors (only 3 on my vehicle, 2 downstream and 1 upstream), the 0 ring gaskets on the upper plenum/intake, cleaned the throttle body, new MAF sensor (though i'm still only getting highs of maybe 12 when at 2200 RPMS), DPFE sensor, cleaned the EGR valve (though still couldn't get the valve to open when i had it off the car, not sure if it's supposed to be able to do that even), replaced the radiator (had leaks and the cap was shot), oil change with a new oil filter, new overflow tanks(they also had holes/leaks), my fuel line ended up getting melted on the egr pipe (forgot to move the protective mesh back) so replaced the fuel line.
I'm now about to replace the fuel filter and the air filter.
I consistently am getting a misfire on cylinder 2 code. Though my friend who is very knowledgeable and experienced with Ford trucks/engines. Has looked over the spark plugs/cables and we even re-crimped the cables we suspected of being faulty. With no change. We found slight air leaks in the upper plenum and have used JB weld (plastic) to repair the small cracks....
At this point as i'm sure many of you are now after reading all of that (sorry for the lengthy comment) have a bit of overwhelming feeing or head is spinning.
I'm at a loss, 2 mechanic shops i've taken it too, are at a loss as well. Between the two of them its over 100 years of experience combined..
Last night the cel was actually not on anymore and I hadn't cleared the codes myself so i thought.. maybe it was a clogged fuel injector or something from my replacing the fuel line. Though today again, it starts sputtering/stalling and cel came back on for misfire on cylinder two..
I don't see any arcing or issues with the firing.. it starts up and seems to warm up fine. Then just starts acting as if its going to die. Then put it in reverse and it almost DOES die, though putting it in drive or park will keep it running enough to stable itself and i can put it drive and it drives .. more or less ok .. but pretty shaky vibrations at low speeds..
I guess what i'm getting at for a video is... when there are so many possibilities for the cause.. and i've repaired just about everything i can possibly think of next to just rebuilding the engine. It's doesn't appear to be a lost cause.. both mechanics and my friend all say the engine doesn't appear to be close to seizing up or anything. It's just very frustrating, embarrassing (because I have a stereo in the truck that is 2x what the truck is worth. i would really like to be driving a truck that actually works AND have a nice stereo. haha)
Mostly frustrating because I don't have the money or now even trust (one of the mechanics charged me $450 to move my spark plugs at the distributor to the correct firing order (maybe 10 min? ) then did a smoke machine test and said they didnt find anything.. yet i found many areas of air leaks when i picked it up.. AND it was still not driving well...
OK i'm done.. If you could use any of this and if it gives you inspiration.. awesome.. if it even sparks an idea for the next area i should be looking. even better. if it helps others NOT go down these rabbit holes , effing amazing.
Now that i've taken most of your day by making everyone read all of this, i'll let the process take it's course. Again, would be cool to just have some sort of notification if it does inspire for a future video.
Thank you for all that you do!! I only recently subscribed but when in the middle of projects, your videos have helped A LOT!!!.
-Kamikaze
Hi Ratchet , my 2001 Toyota Siena hesitates at low rpm but when i put higher octane fuel in it the problem goes away , the car has 189000 km on it and the check engine light is on , Thanks a million for your great videos.
I love your videos brother!
Thanks Chief !! Brilliant explanation. BTW guys,On V engines, Bank 1 is cylinder 1 side.
Thanx that helps
Dear Lord, what a hero!
I'm a physics major and I've been going nuts trying to figure out why one of my cars is running so rich it's essentially squirting fuel out the tailpipe.
Now I can measure it and troubleshoot it. Heck, you can even find vacuum leaks by spraying fuel around the engine bay and watching the graph change.
Nice tutorial on the trims, which I keep reviewing for the PERSISTENT P0171 lean code! I cleaned the MAF sensor with MAF cleaner a couple times, then tried new sensor, it kept returning so I took to shop for vacuum test, he said MAF sensor. I tried another new one, code returned. There really are no symptoms but I was going to test fuel pressure but I don't have a test port and it seemed a pain and I was told it's rare on a Toyota and there are no other idle or performance issues. I'm back to my original MAF sensor and may replace just to get rid of that variable (though two others didn't fix anything). I'm thinking O2 sensor or injectors, but I'm out of ideas.
Very useful information.
Great foundation to start a diagnosis . Complete visual under hood , etc. Then scan and read the data . Test before replacing parts !
Nice video brother 👍
Hey hey hey, thank you for this very informative video
Thanks for doing this video it helped me learn A+
Thanks bro, I understand now what's going on.
I appreciate it
This video was extremely helpful
Yes more videos on that yukon please
If you have a BMW, the front 3 cylinders are bank 1 and the rears 3 cylinders are bank 2. This is very uncommon for the average car but important to those with in line 6 cylinders.
I also had a power problem recently with my 8.1, figured out the O2 sensors were bottoming out to 0 mV. The issue did not trip the light but had set a code in the engine control module.
Amazing. Learning a lot
normal people cars: "oh no! the check engine light came on!"
me, in my car: "oh no! the check engine light turned off!"
yeah, if that happened on my car, I would definetly be concerned lol
I bought my car with a check engine light two years ago it's still on I took it to AutoZone they said no codes I took it there because Scotty Kilmer told me too
Mine said "Tilt" the other day; I just kept driving.
Snotty Kilmer would say run.
Thx for the real under the hood diagnostics.
Thank you Ray Romano!
Great video champion
Great videos!!
WOW .man your are amazing .great information thank you so much
Reading mathematics equations from a rudimentary computer it must be hard but you make it sound easy.. much thanks great job
You can do it :)
Well explained!
Nice video as always. But! What about Diesels without oxygen sensor? How can I diagnose mine? (TDI owner here 😀)
My recent leaking flexi hose just ahead of the oxygen sensor caused a lean condition and my motor smoked after wot. Diesel engine so no trims to view but the repair fixed issue!
Good teaching👍👍👍👍👍👍👍👍👍👍👍👍
hi! i have a fusion 3.0v6 2010 and my oxygen sensors are 0.04v in idle, the short term fuel trim bank 1 and 2 are +0.9-1.0 if i rev it up the oxygen sensors voltage moves up but in idle is stuck in 0.04v (already checked for vaccum and exhaust and there's no leaks. maybe a fuel injector? what you think?
Runs rough but no light? Valve Cover Gasket? This exact thing happened to me and it was an old brittle gasket not sealing perfectly.
🤔
Mechanic once told I blew a seal; I said "Fix the damn thing and leave my private life out of it, ok, pal?!" -- Wet Dream by Kip Addotta.
@@chaleorta The brittle gasket allows air leakage, which affects the Positive Crankcase Ventilation system function also. In turn, depending on the engine design, the 02 sensors start showing a lean (too much oxygen) condition, even though that's not actually true, and tell the engine control computer to reduce the airflow to the engine. So now the throttle body flap (air intake of modern engine) is partially closed off so engine is being somewhat asphyxiated, causing a loss of fuel/air balance as it tries to keep running on less oxygen, leading to rough running.
Mark H. A brittle gasket also can allow oil to seep into the spark plug holes. Which was my case. Originally, I replace the spark plugs which fixed the misfire but only for a month. I the replaced the valve cover gasket, and it fixed it.
@@StyxYRenegade Interesting; never thought of that leak path. :)
I've had good luck with my Actron 200 something or whatever. Live data feed and can also graph.
Good stuff!!
Great video good info as well.
What model scanner is that autel u are using that u graft 4 components with.
Awesome video
Great videos.
I'm subscribed and hit the bell but still don't get notifications.
Hey @
Ratchets And Wrenches I have a terrible experience. I drive 07 Honda CRV 2.0l (Stick/Manual) than lacks power. When I floor it on the road, the car doesn't react to it. But when you pull your leg off the pedal, just before your leg is off the pedal power kicks in. So by deduction, when you lightly touch the pedal, power response. I took the car to a dealer for scanning, first I got a code that AF sensor failure, changed that. They later suspected PCV Valve that was ok. No more codes. Injectors work fine. Fuel pressure ok. Oh, lastly. On the scanner, it showed a bit of lean condition. Where can I go to look next?
Please weigh in on the common Honda S2000 off-idle stumble and low rpm rough running problem that has been discussed ad nauseum on UA-cam. I'd love to hear your opinion. Thank you very much!
Hello, I love your videos, they're right to the point and easy to understand. My problem is this, I have a CRV 2012 and every time I start it and drive it, fir the first 5 minutes the car shakes when going from 20 to 40 mph. After a few minutes of driving, this problem dissappears. I checked the #1 sensor and it throws. 02 to -1.5, my LTFT is 12.5% and STFT about 10%. What can be the problem. No check engine lights are displayed. Thank you for your help.
Hey ratchets, got a 2004 Honda element no code map engine but at idle in the morning and when motor is warm, I'm getting around negative 15 both short term and long term. It smells of exhaust gasses quite heavily but engine doesn't run rough at all and only symptom I'm having is I feel I should have more power. Have new oem air fuel sensor and the rear o2 as well. All my live data looks normal like map, ect, ait, etc. Do you think since these engines need to have their valves adjusted and it's a new to me car with 160k, that valves being out of adjustment can cause a rich condition? Thank you.
Are you going to break down how to find what the actual problem is?
I have a 2016 Kia Forte 5 with a intermittent rough idle and no check engine light.
Welcome back
Change your air filter you’d be amazed, also check air intake hose to the throttle body to be sure the rubber hasn’t cracked
Change air filters spark plug all coil and changed a cracked hose stil vibrate at 600rpm when idle at red light or parked idk if it could be the battery now .. dodge D 17
Thanks this helps a lot. My LT fuel trim was moving higher, my car doesn't trip the CEL until 15%, I used some lucas fuel injector cleaner and replaced a cracked hose, that seemed to help. My mechanic recommended putting in 44K once a year. What do you recommend? Lexus RX330 182K miles.
44K AND BERRY’S MAN’S CHEM TOOL INJECTION CLEANING AND RED LINE WORKS GREAT FORD ME 5.0 1989 1998 F150
Great video, since scotty is moving out can you move to Texas please?
Thanks for the video. You may of mentioned it but I missed it. What scanner is that?
hi there, I got my car low idle rpm when cold and high idle rpm when hot. idle control valve and all sensors are new.. I suspect it's my ecu just to old and maybe burnt (common problem with my car), but I also think: is it possible that somehow my ac idle up in-out hoses are installed incorrectly? it doesn't have obd ports.. thank you
smart mechanics will realize the value of this lesson! THANK YOU! (I'm saying this as I already know it, but THIS was an EXCELLENT crash course/summary!), and helps people associate symptoms, data and causes that are frequent for many performance/emissions issues!
Great video and explanation but it might be mentioned that the 14.7:1 air-fuel ratio is calculated by weight, not volume, as outboard motor and chainsaw fuel mix is done. So that would be 14.7 lbs of air to one lb of fuel.
The 'sleeper' I keep forgetting is a stuck open EGR valve. Often not much to point to the diagnosis as a cause for bad idle. Gotta remember to check.
I think this is the rough/low idle problem I have in my 01 Saturn SL1
Great point! Now would that cause a rich condition (due to reduced oxygen in the exhaust or misfires) or a lean condition (due to excess airflow into the engine)?
@@thromboid It's been a while since I thought about this but I believe the fuel balance is usually not much changed. Scannerdanner did a handful of videos on this topic, and he explained that the recirculating gas is largely inert, neither adding much fuel nor appreciably changing oxygen concentrations. Pros seem to make this diagnosis on the basis of pattern recognition, or maybe trouble codes in more modern cars. Bumpy idle is the clue, improved at higher throttle. So this presents like a vacuum leak without the characteristic WOT improvement of a lean condition as seen with a vacuum leak.
My Eco mustang when running on stock tune is 14.0 AFR on idle and can drop to 9.4 AFR on WOT. On my tune it used to runs at 14.7 AFR on idle and 10.8 in WOT. Its has 84k. On the tune it used to run at 12.5 and stock was 11.7. It has been a slow but gradual loss. Piston compression on all cylinders are 130 psi. Have not check yet for fuel trims on my Launch 129x scanner. What are your thoughts before I dive in any deeper. Could be an injector stuck open.
What if you have high long term fuel trim (10%) and short term at 5% and the O2 sensor is reading high at 0.78 or thereabouts consistently? Does that mean the O2 sensor is failing? My bank 2 cylinders are carboning up and running rough. Would disconnecting that O2 sensor help diagnose the issue?
I have a 2006 forester, the problem is , when I come to a stop sign/light sometimes the engine will shutter and sometimes even die,, but will start right back up. There is no check engine light. there had been a check engine light on for quite a while so I took it to a shop and they discovered that someone had put one of those "defowlers" in where the down stream sensor was then put the sensor on top of that. I have heard of that to try to trick the computer, anyway, they took that out and so far the light has stayed off,, it runs great with plenty of power and it idles very smooth. I did put in new plugs and wires also both new o2 sensors, they are the good ones not the cheap ones,, I didn't even notice the gizmo someone had installed when I changed the o2 sensor. so I wonder if you have any idea. I even replaced the maf sensor. thanks. Vernon
So if I go with a slightly bigger turbo which will move more air will I have to get my car retuned? I won't be able to keep the same map or will it just keep making the same power but easier?
Can you elaborate on this for turbo charged engines and readings at idle vs under load,... Under load when turbo spools intake becomes pressurized what happens with intake leaks?
hey there. my o2 sensor downstream is reading 0.7V or so (2012 honda civic)... and I'm getting worse gas mileage..... short term to long term fuel trim is around 7%...does this mean lean condition? I'm burning more fuel.. or do I have a clogged cat? what should I try first? change the o2 sensor or change the cat? I don't have any vacuum leaks that I know of..
Hi, can an egr valve cause lean codes? I have a jaguar sv8 4.2, supercharged, I replaced the brake booster seal on the throttle body manifold… as the tube was really loose, I was also getting a p010b, I replaced the maf on the sensor reading crazy air flow… now it runs perfectly, no p010b error.. but still getting lean codes both banks after a long drive, but now the CEL has stopped coming on… I’m still getting cat under threshold every now and then… when I did the booster seat “not the easiest to get to” I took off the throttle body and it was caked up so I polished it all up… but now I’m thinking if that was that bad, then maybe the egr is as well and sticking… fuel trims seem to be within reason driving on the motorway… it’s low rpm when they seem to go high on ltft
Any suggestions would be great
Do you have any knowledge of understanding fuel trims on a launch x431 diagun iv,I don't seem to understand it
Hi great video,you know your stuff.I hope you can help me.I have a 2002 mustang gt with only 76,000 miles,and in excellent condition.5 months back I had an slp loud mouth 1 exhaust with an x pipe installed.Iy ran fine for months but slowly developed a shaky idle.Now it is idling rough enough to feel it in your seat.It also makes these little puff sounds while idling, but doesn't make the puff sound for about 3 or 4 minutes when it starts to warm up.After it is warmed up it makes puffing sound every few seconds while idling. Never did it before new exhaust. I was told it is running rich too much fuel and that is why it is making little puffing sounds.Car was hooked up for hours the other day and produced no misfire codes,although there was a code for a downstream oxygen sensor on bank 2.That was fixed but it is still making puffing sound.I was told I need a tune because of x pipe and shotgun resonators I had Installed. They say it is the new exhaust making it run rich and because of xpipe it needs a tune If you had any ideas that would help me alot!Dies this make sense to you.I want to dyno tune and the tuners said they can adjust my levels and get car running again.Thank you.
I’m assuming by now it’s fixed, but with aftermarket exhaust it doesn’t make it richer it can make it leaner (too much air) bc the new exhaust is less restrictive. A tune would be most likely necessary
I'm having an issue with my g35 my bank 1 fuel trims are reading high in the positive side, my upstream O2 reads at about .300volts and I think it's my cause for my p0300 code. I did a smoke test today to look for leaks but everything was sealed any ideas on what to look into next
Hey hey hey!!! Is good to have you back. Question: Is it a good idea to blow (or vacuum) the air filter once in a while? Thanks in advance. Greetings from Chile
Hi, You have to be very careful if it tares you have done more damage than good. If you have to just gently hit it against something to get the dirt off.
My 06 cobalt is running lean with a po171 code. It's a 2.2L manual transmission and my stft is 0 and my Ltft is 19.5 can u possibly help me figure out what to do next. I replaced the fuel filter, ran a fuel system cleaner, did oil change, thought I fixed the vacuum Leak. But now I know it's maybe a maf or o2 sensor but I hate chasing. Maybe u can tell from the numbers what it is.
So I got good trim readings for both short term and long term at idle but at 2500 rpm’s bank one long term goes to -10 %. While bank 2 stays near zero. Would that be a leaky fuel injector. ?
Very good.