How to quickly identify a vacuum leak using fuel trim and water
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- Опубликовано: 26 авг 2024
- 1998 Chevy 5.7 misfire (P0300) and fuel system too lean (P0171 and P0174) trouble codes AFTER the intake manifold was removed. This is the same van that I shot two different videos on, one for each of my channels.
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1998 Chevy Van 5.7 No Crank and Misfire Troubleshooting • 1998 Chevy Van 5.7 No ...
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1998 Chevy 5.7 Misfire (secondary ign-injector balance-psi transducer testing) • Video
In this third installment, I was called back to the shop after they repaired the injector problems for the two cylinder misfire.
Engine Performance Diagnostics chapter 1
Symptoms
- popping/backfiring through the intake
- hesitation
- poor idle/stalling
- misfire
Fix
- replace o-ring around the fuel injector assembly in the upper intake manifold
Tests shown
- how to use fuel trim to identify a vacuum leak
- how to locate a vacuum leak with water
Tools used
- water bottle
Meguiars M9911 Spray Bottle W/Sprayer
www.jbtoolsale...
- scan tool
Autel MaxiSYS MS908 Diagnostic System with Wireless VCI
www.aeswave.com...
Related videos
- Understanding Short Term and Long Term Fuel Trim (an SD Premium video) • Understanding Short Te...
- Causes of lean condition trouble codes P0171, P0174 - GM 5 3L • Causes of lean conditi...
- How to use Fuel Trim to identify the cause of a P0171 and P0174 code • How to use Fuel Trim t...
Playlist
- (Chapter 1) Misfire ID, Compression Tests, Vacuum Leaks, Fuel Trim, Head Gasket, Restricted Exhaust, Low Power, DMM
• (Chapter 1) Misfire ID...
For more information on this topic, I have written a “field manual” called Engine Performance Diagnostics which is available at www.scannerdanner.com as an eBook or paper book.
Want even more diagnostic training? Whether you are a DIY trying to fix your own car, someone looking to become an auto technician, or a current auto technician that wants to get more into diagnostics, subscribe to ScannerDanner Premium www.scannerdan... There is a 14 day free trial.
On ScannerDanner Premium I will bring you right into my classroom at Rosedale Technical College. You will find page for page lectures taken right from my book as well as exclusive classroom type case studies. What is so special about these classroom case studies? I pull live problem vehicles directly into my classroom and we troubleshoot them in real time, using and applying the theory and testing procedures we learn during the classroom lectures. There is no better on-line training of how to troubleshoot automotive electrical and electronics systems anywhere!
Disclaimer:
Due to factors beyond the control of ScannerDanner LLC, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. ScannerDanner LLC assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. ScannerDanner LLC recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of ScannerDanner LLC, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user and not ScannerDanner LLC.
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i wish there is a mechanic just like you in CA that actually diagnoses a car not just throw parts at it.
There is, keep looking.
Thank you for this great video. Talking about water, I used it in the past to detect vacuum leaks and it is easy, safe, and a successful humble method. However, I have met more than a couple technicians who said to me not to use water because it is going to get sucked down into the combustion chambers. What I said to them was that even if there would be a few drops of water in the combustion chambers, the compression ratio is not gonna be affected that much and no damage is gonna occur due to using water for checking a vacuum leak. I am actually impressed by the way you check and test vehicles' performance issues. You are in control of both, the simple method and the very advanced methods to find and pin point the root cause of engines performance problems.
God bless you and God bless your good work.
Legend. Had something similar wrong with my car. Fuel trims were ridiculously high while under load but it was fine at idle. Checked for a vacuum leak using this method but no joy. Watched your video on MAF readings etc. and found out I had a bad MAF sensor. Keep up the great work Paul, definitely going to sign up for your premium videos.
Thanks so much!
some people went crazy when I told them this. But you are the master and we are the students, so everything you say, I swallow it hook line and sinker. thank you very much.
haha thanks. I've definitely heard my share of concerns with this test but I've been doing it for 15 years with no issues and no you will not hurt the engine.
Ever take a cylinder head off an engine with a bad head gasket? What do you notice about the cylinder that was leaking coolant? The piston is clean! That's all you doing with water. :-)
ScannerDanner thank you
Already used the water bottle to help a buddy with a preOBD2 (no scan tool) 4 banger to find a vac leak. It died on startup and when it warmed up it missed horrible at idle, but ran decent revved and had a strong gas smell at the tailpipe. He thought I was crazy when I told him what I was going to do with the water bottle. He stopped giving me funny looks when the motor died as soon as the water hit a vac line connector on the intake. Cut an inch off the line and it ran fine after it relearned the trims.
i have been doing this 20 years and never even thought about using water... i like it
I don't have a smoke machine but I do have a Gatorade bottle and water.Thanks your video probably just saved me a few hundred dollars!
Pete is a customer and like you said you have to take care of the good ones especially, and he is. Glad I can see it on the premium channel.
yes he is
You have to blame the guy who was drinking the beer last time. Lol
haha yep
understanding fuel trim is important I have learned, water test is great for us diy guys no cost for water and effective, never heard about it before your channel. great as always.
If any doubt the water method. Paul ain't lyin. I have an 06 Mercedes E350 in here right now. There PCV system is like the BMW's. A bunch of crappy rubber hoses that have to contain full engine vacuum. If as Paul always says u go OBD ll global and look at STFT then spray a fuel source u will quickly find the leak. Or, get out the spray bottle and listen. It works fantastic. Found the problem in 5 min
Nice Bill. Thanks!
Also, the water test "steam cleans" those pistons! I use the water trick all the time. Screw the haters!
The most confusing things about fuel trim is the jargon. When the computer boosts injector time to add fuel, it is normally in response to a lean situation. When looking at fuel trim you're seeing the response, adding fuel. Of course the cause is a lean signal from O2 sensors. So it's a lean situation even though more than usual fuel is being delivered.
Yes. I occasionally have to remind myself of tis because it's sort of contradictory
That's not confusing at all. Just remember the computer is trying to compensate for something.
@scannerdanner I watched this video in the morning and i actually use this test in a car this afternoon and really work. Well done well done Paul
thank you!
@@ScannerDanner I have a 08 Chevy Express with 6.0 I long term trims usually are at 24% on bank 2 I have p0174 and p0300 rims usually fluctuate weather it's hot cold and I spray water on intake but rpms still fluctuate weather I spray water or not?? When motor gets hot trims go to zero bit if I push throttle trims go back up to 24%??? when I go up hills while engine running it pops just like this one..I'm just trying to get some advice on where I should go?????
Thanks
Dylan
@@Smith93646 pops through the intake under load and trims that elevate at higher rpms is not a vacuum leak. Check fuel pressure and MAF. Unplug the MAF and drive it and see how it runs as a next step
@@ScannerDanner well dang I was on the wrong track but okay thanks I'm about to to that now
@@ScannerDanner I unplugged the MAF SENSOR IF WOULD CRANK OVER AND START BUT WOULDN'T STAY RUNNING?
I've been slacking on your videos Paul but we had a family emergency and I'm catching up. Great tip on this one...I did watch the twin misfire and it was a great case study. Always enjoy hearing from you.
Hello. 2003 Mitsubishi 3.8L V-6, 220,000 trouble free miles. Fuel economy is where it should be.
LTFT 1&2 are +12.5% at hot idle. But goes to 0% and stays there when revved to 2,500 rpm.
STFT 1&2 are 0% at hot idle. When extra fuel is sprayed on identified leak of intake manifold (leaking o-ring, I used smoke to find) the STFT immediately goes to -6 and then returns when the extra fuel is burned off.
Could this intake air leak thats affecting both banks cause the truck to go into a limp mode, giving me these codes?
P0335
P2135
P0340
Also, why does LTFT go to 0% when under load? Thanks!
Dam you was not lieing about that, know i need see what kind ive got to watch it again and show my firends. Keep up the good work and God bless you and your family
lol 50% STFT PCM is basically saying "Please grab the closest gas jug and dump directly into intake manifold to reach 14.7/1 or fix the vacuum leak"
I have Found that smaller leaks are easier to find w/ a smoke machine.
I'm using this all the time. ODD on fords when vehicle stalls the trims default to 45%. (have also seen other default KOEO values incorrect until started) Maybe that's just my scan tool. solus ultra.
Scannerdanner Your just a Genius Brother,Great work.
I personally have a Autel DS808 and it's like my right hand. I personally like using Brake Cleaner for vacuum leaks and I know of all the hazards but I like it. It's not like I'm spraying it on a glowing manifold.
This test is sooo cool , simple and effective.. since I watch your videos I didn`t not need it but I will use this method for sure when I suspect a vaccuum leak on a vehicle
thanks man
Loving that water test. That's like level three MacGyver.
So I'm assuming I'm listening for that squeaking noise of the vacuum leaking trying to pull in the water? I've never seen this trick
Exactly and once you narrow in on the sound you can see it getting sucked in
Is it okay to let the water goes in?
@@alvinlawanto my exact thoughts
I have used the water method for finding vacuum leaks many times, I think I actually picked it up from another one of your videos.
I'm gonna have to build me one of them thar water bottle diagnostic tools. Certainly alot cheaper than my Maxisys was ... :)
My buddy owns a '96 Tahoe that defeated me a few years back. Was a no-start - he went out one day, and it wouldn't start. Threw a junkyard computer in and it fired right up ... on 6 cylinders. We played the parts-changing game (bad bad bad ...) and $1,000 later, I felt the slightest improvement, but still a dead miss. Now that I've been watching you, Eric O., Ivan, and ETCG, I know what I need to do to get a handle on that thing. That truck has been eating at me ever since! I don't like defeat, lol. Now that I've got a Maxisys and a back-probe kit for my meter, I think I may have hope of getting this thing hitting on all 8. Going to try the newfound knowledge out on it at some point. THANKS for the great videos!
Make sure the PCM you used was from a v8. if it came from a 6 cyl. engine, it will only have programming for 6 injectors. A re-flash will take care of it.
I actually just found this out last week! I finally have a scan tool capable of reading the VIN off the ECU ... and lo and behold, it came off a '96 S10 Blazer 4.3! I suspected this, but couldn't prove it. That junkyard really ripped me off.
We ended up finding a guy on eBay out of OH that reflashes used ECUs to the VIN you email him. $90. Should have this thing actually running correctly for the first time in 5 years by this weekend. :)
Next purchase is going to be a laptop and a J2534.
HAHAHA! No thanks Mike - got some here for free. :D
And as an update to this post that I forgot about, that Tahoe is now finally hitting on all 8. Runs like a champ once again. :)
Hi Paul , thanks for every share you are a great man , hope you will look my problem too , STFT at idle is -7 and LTFT is -14 and at acceleration STFT improves , it is Toyota Camry 2010 model, need some hints from your expert side to go around
leaky fuel regulator, injectors leaking down, clogged air filter, coolant temp sensor misreading? is car getting up to temp, stuck open thermostat?
2005 Toyota matrix 1.8l, ltft at 10.9 when first warmed up at idle ltft goes to 19.5 after 30 min drive, new intake gasket and throttle body gasket, can't find any vacuum leaks with water, any suggestions
Thanks again Paul. Keep the videos coming!
Excellent vid.And that’s gonna be an awesome vacuum leak/fuel trims lesson.
Thanks for the info. Man I love you videos
I appreciate that! Thank you Bruce
Using the water what dose it do with a vacuum leak suck.in the water? Idle change?
Great videos and thank you for sharing your knowledge with us, blessings
Good diagnostic
Hey Scanner! Walmart carries real nice empty spray bottles that might reach into deeper, tighter area's with a nice spray mist.
Thanks Blade
Nice quick diagnosis Paul.
When my fuel trims are very high and have misfire in cylinder 1 and also random misfire is it a vacuum leak? I have serious lag when pushing gas pedal moderately and all the way
your an excellent mechanic dan love all your video's those machines r pricey but with everything changing these days u need em special tools etc.... they pay themselves off.
thanks man! Oh and my name is Paul :-)
It's okay, I get "Dan" all the time from my last name Danner
PLEASE! The school pays for the tools he just "borrows" them from the school. Wonder why the school allows this type of activity? Other people pay for their tools he gets the schools and uses them! Haha JOKE!
I hate those intakes ware the spider injectors like that. It's so hard to get that plug to seat in the gasket
You love your work Man ! - GREAT - keep it up !
thanks Paul you always help us really you are HERO do not give up please
Hey it's me again about the 1994 s10 4x4 ls put the spider in been 3weeks and had take it out they well orileys sold me a part that they didn't order got the other one in running perfect but when the other spider messed up it made my transmission we're it won't go into overdrive manually shift it 1st 2nd half to floor it it will hit drive and it will change down when slowing down .but the other thing is when you start it it's fine when you put your foot on gas when it does it .sounds like vacum or something
so can I dump water on the injectors ? they are on the intake , the electrical connector's ect .. that's safe ?
please answer I want to do this water test
Great Video...Was driving my 2002 Escalade across TX and noticed LTFT + 13 to 18 % at light loads while cruising, both banks. While STFT was about 0% I did get a P0440 Evap fault that morning so that's why I was checking it. Also had to replace front bank 1 o2 a few weeks ago for a burned out heater circuit. I cleared code and it didn't come back. At idle Short & LTFTs are normal + or - 3%. This doesn't seem like a typical vacuum leak with readings normal at idle. Any ideas ???
Update started with fuel delivery. Found fuel pressure a little low at 45 psi at idle. Noticed pressure dropped off to zero 2 minutes after key off. Pinched return line held pressure. Replace regulator and correct that plus gained 3 psi more at idle. Test drove saw some improvement in LTFTs. Cleaned MAF test drove and LTFT dropped after driving about 10 minutes. Plus improved acceleration and idle. Thanks!
@@BlueEyeTableRockLake Your 2 comments have perhaps helped me figure out what's going on with my 2007 chevy van, 4.8 L V8. It has a couple issues; getting codes related to O2 bank 1, sensor 1 as well as having LTFT on both banks at 25% (bank 1) and 18% at idle. STFT numbers are good. Also, the other three O2 sensor values and behavior look normal. When i rev it up and hold it for a minute or two the LTFT numbers drop off a little but not much. At first i was thinking it may have a vacuum leak but now beginning to suspect a dirty MAF. I will explore that. Am i correct in saying that a dirty MAF will cause a lean condition that the computer will then compensate for by adding (LTFT in high + range) fuel? I think i've got that figured right but if i'm off the mark i'd appreciate feedback from anyone who has better grasp of this subject than me. I'm still learning about all this stuff which is new territory for me and my diy journey.
I cleaned my MAF too, but it didn't change my somewhat high LTFT at light loads. I'm not sure if dirt cause rich or lean condition with a dirty MAF. @@botchvinik8668
Hello scannerdanner,
I have a question on one of your videos that I previously saw but can't find it anymore. it's a misfire on my car 07 nissan versa and I need to check ignition coil but it's underneath the intake and no way to disconnect and check. Any suggestions?
Hello I'm from Israel and enjoy watching your movies very much, thank you very much. A vacuum leak test can also be done with carburetor spray.
Shoot! You can hear that vacuum leak!
My 2001 blazer 4.3 l threw me a code p0135 n p0300 I check fuel trim dont understand it .. 2long -6.3 2short -1.6 and 1long 25.0 and 1short 24.4 if u can help and understand the #s thanx
You fix this? Define the P0135 code. (O2?) And if so, what is your O2 signal voltage doing?
Hey scanner danner I have a 2012 Hyundai Elantra with the code p2096 any idea what's wrong?
hey Paul Ive been spending a lot of time on your premuim channel and just came over here for a look and noticed you had a snap on verus edge on this one, i have a guy willing to sell me a plain snap on verus for $1500 with the 15.2 update, do you think this is a good start, am I missing out much on not having a verus edge that is updated currently other than the year of cars I can work on, I also played with the idea of a modis ultra but its only a 2 channel scope, its $2300 but a bit newer, ive been putting it off for awhile now but Im trying to make a well informed decision, just would like a little bit of input from ya, thanks Paul, plus I greatly appreciate you doing this for all of us, the $10 dollar fee a month is very little compared to the amount of knowledge and information you put out for us and your worth so much more, but at the same time thanks for making it affordable for us that dont have much $, again thanks and hopefully we will here from ya
You really love your job,thanks
And I was about to drive my old Jeep into a lake to see where the bubbles come out.
👍You're the man as always!
Very nice test.
Great show..im looking for a inexpensive obd2 scanner that will do cylander comparison and injector drop..will the blue scanner do those? I'm having a hard time getting a yes or no. It's for a 24v 5.9 cummins..thanks for the great video
no, if you want bi-directional controls, you will be very near $1000 for a scan tool that provides those functions
I'm color blind and could not tell what was happening when he squirted the water. What were we supposed to be seeing? Was it getting sucked in somewhere? If so where? I've watched that part 10 times and my eyes just don't see it.
my fuel trim has high numbers when in idle (parked). short-term and long-term add up to +17. I believe I have a leak on the exhaust manifold near the O2 sensor. the car is stalling when im at a stop sign or red light. only stalls when I have my foot on the brake or put the car into reverse. the car stalls and I sometimes hear a bang after it stalls. will this stalling cause damage to my engine?
I dont like the bang noise symptom but no, a stalling issue won't damage an engine
@@ScannerDanner I'm hoping it's just the motor mounts or the exhaust hangers. ty
What a nice easy test
Man ur the best!! I love all ur videos!!!!
Dont need to know wny fuel trims to hear that one. Definitely the carburetor gasket!
No carb on this one 😉
Thanks for useful video.
We use brake cleaner or a similar aerosol cleaner. Is water better, worse or just another viable option?
After catching the underhood of a customers car on fire while they watched, I stopped using flammable liquids to find vacuum leaks. Also, the water test is more accurate in most applications
How profitable is it to be a mobile diagnostic guy? It's something that appeals to my interests.
you may not get rich but there is always work to do... look at how many garages have so much difficulties in diagnosing electronic stuff on modern cars... they pull the codes and if that does not say "replace part X" than they´re more or less finished
Very profitable if you are accurate. enough to make a living doing it and working for yourself.
It's dangerous to use water like that. I've already seen a guy bend a connecting rod by doing a test like that. I think it's more safe to use intake cleaner if you don't have smoke machine. Just my opinion... Except that, good vid on fuel trim...
No it is not. I've been doing it for 15 years, on hundreds and hundreds of cars and trucks. And it is definitely NOT "safer" to use a flammable source. Ever have one intake backfire on you when spraying a flammable source? If you have, you would rethink what you are suggesting.
What was the guy doing that bend a connecting rod? Dumping it directly into the intake? Seriously, I'm not being a smart ass, I really want to know. Thanks!
Yeah, you're rigth about the intake cleaner... It's not more safe for the worker, it's more safe for the engine.
The story about my co-worker is the following. He suspected a injector seal vacuum leak on a Volvo 850. By adding water again and again, because it was not absolutely sure about her diagnostic, he eventually caused A hydrolock, and he bend a connecting rod... I know, he probably put to much water, but I think is a risky procedure.
And I absolutely not want to be a smart ass... Lol !
Being myself a teacher in automotive mechanics, I'm really impressed about all you're video and diagnostic logic....
Thanks again...
You teach Automotive and you seen somebody bend a connecting rod?
Please stop teaching now because you're just as much a dumbass as the person who poured the water.
Can we splash water anywhere and everywhere under the hood without worry? Even into the alternator vents?
Well, I wouldn't advise throwing a bucket of water straight into the throttle body unless you want to rebuild the whole motor. You'll likely bend the pistons if it's running or cranked with water in it (look up hydrolock) :) Small amounts are fine even in the intake because it gets turned into steam in the cylinders. Everything else on a motor except inside the distributor cap tolerates water pretty well. As far as I know the alternator doesn't care about water and I've never had a problem with them getting wet.
you are aweson, congratulations ......
Hi Paul; what will make a 1.6 four banger(daewoo/chevy nubira-2001) go into open loop above idle (1000 and above) ONLY when stopped? (closed loop ok at idle,nice swing of the o2 sensor); as soon as you rev it past idle speed, boom, oxy sensor pegs at ~.85V; this w/the car stopped,ONLY; slightest load on the engine,and closed loop returns: for instance,its enough to turn on the A/C and the high beams,and it´s ok;; ok also when the car is moving; it´s always a problem at the emissions inspection; been driving (actually,the other way around,lol) me mad for 2 years now,all sensors give good values(temp,map,tps,tried a few o2s); no codes; the car was converted to lpg,does it running gasoline or lpg;it will also stay in closed loop if i create a VERY SMALL leak on the vac.hose to the MAP; have an adjustable 50 cent plastic fish tank airline controller connected to it with a plasticTee, messes up the idle a very tiny bit,but it works;
When it goes open loop,the scanner says:"Open loop due to load or decceleration"; neither of these beeing factual; none of the o2 sensors i tried were originals; they were from bmw,jaguar,etc,spliced into the nubira wiring.
It is becoming more and more difficult to answer questions here. I have 80,000 people asking me for help now. So I have created a forum to help you guys better. It is free to join and we can exchange pictures, wiring diagrams and waveforms if needed to help guide you through the process of troubleshooting your vehicle. Thank you so much! Hope to see you there.
Paul Danner (ScannerDanner)
www.scannerdanner.com/forum/post-your-repair-questions-here.html
I did worked fine after no codes good test drive. just haven't found a solid answer for it
Awesome video, very informative. Thanks! =)
2 cylinder misfire?? Bad Crab Cap?
Hi i have a question if my BlueDriver counts 1 misfire while a trip and next day another cylinder counts also 1 is it a leak vacuum or crank shift sensor or clogged injectors
My car is mercedes e280 2006 model v6
I have to worry about bit about a garage that can't diag a vacuum leak.
thanks i just found a vacuum leak with a scan tool and water test.
ScannerDanner, what are FT (2) numbers? I've seen ones listed as STFT1 & STFT2 and also STFT11 and STFT22 which don't always match up but I was never really sure what the 11 and 22 ones are. I just go by the regular ones and get the job done. Thanks
Most FT (2) numbers are not used and are listed at 99% all the time and they never change. There are some manufactures that do use down stream fuel trim, so be careful. But in general, I never pay attention to those numbers.
Thank you for the reply. To they are downstream fuel trims? I have seen them change but I never really paid much attention to them when I see them.
Good video
I cant find a vaccum leak but my stft is 10 to 14 at idle & rpm is on 750, what to do now ?
I mean is there any other reason for high fuel trim ?
Plz help !
what are your trim numbers at 2500 RPM steady throttle in park?
What if on Bank to your short term trim is normal? but long term fuel trim or at 15%
LTFT learns from the STFT so you still have a lean condition. It's just been compensated for. Treat it the same way as I showed in this video
👍
so how come the water doesnt hurt the piston as in hydro lock???
Not enough of it and the engine is running. Just don't put a garden hose in there
Sweet! Thanks Paul.
thank you!
Hey..i really like and see ur videos..m from engineering background but have been hearing of not to let the water get inside ur engine. Again i don't know what are the facts behind it..but can we really let the water inside the engine? M afraid if i damage my engine. Sorry for my bad knowledge...
The small amount being sucked into the engine just steam cleans the combustion chamber at worst.
Dan, im a technician that badly wants to learn engine performance and diagnosis. I see in some of your vids u label them in chapters. Do you offer videos right from the easiest stuff and train up from there? If so how can i have access? ,Thank yotu
The chapters correspond to a book that I have written for my Engine Performance class at Rosedale Technical College. For more information about the book and my Premium RUclips channel, go to my website www.scannerdanner.com
Thank you!
Thanks for the reply, will do!
I need some help please and I don't ask for help very often. I have a 1998 GMC 5.7, have a lean code on both banks come up, I have smoked, sprayed chemical and water bottled; no leaks found. Sometimes the light will go out and stay off for a while like the other weekend after the light went off I drove 360 plus miles no light until I got 1 mile from home then here it comes on again. Basically at idle numbers run st 0.08 to 2.3 and lt runs 16-27. Steady 2000 rpm lt will drop to around 16. Additionally I have changed out the maf sensor from another identical truck system and cleaned both. MAP sensor was also exchanged. At first I looked at the trottle body maf cover gasket for it seemed loose seal so I couldn't find a new one at the local parts store so I put a heavy dose of form a gasket 2 around that until I find the issue. I just checked the o2 sensor readings and all four readings of volts move up and down 0.10 - 0.900 but at 2000 rpms bank 2 downstream sorta sits at 0.110 at idle it responds more. Thanks for any help!!!
First test, what are your upstream O2 sensors reading at WOT?
They should both be full rich (800mv plus, flat-line)
This will be our fuel delivery test.
After this, I may want you to check this for an internal vacuum leak. We will talk about this after the O2 WOT test
Thank you for your response! I now have to apologize because I had a good Innova scan tool on loan so instead I now have a crappy cheap one and trying to get you that number will not be accurate now, for it apparently can't receive or process data fast enough and about the time you start to get a 2000-2500 rpm reading it shuts down on me, but best I can read in an intense o2 reads less than 800mv but seems to be worst on bank 2. I did see a reading of around 695.Neither bank holds the higher 800mv though. At idle both banks will move up and down to the 800mv. Far as fuel regulator I installed a new one and cleaned injectors last year. Another note: vehicle will sometimes buck mostly seems underload on the interstate then smooth back out, it's rare occurrence. I checked the IAC today, it's working okay. Motor runs great except for the codes. If you need more accurate numbers I probably can get them Monday. This morning with engine cold I poured 2 litters of water on intake and fuel port, no problems showed up. Sorry again. @@ScannerDanner
Do this test during a test drive (allows more time at WOT) (also, you only need to wind out 1st gear, no need to take chances with speed) and try to limit the amount of data parameters you are looking at. This speeds up the data a ton on some tools.
OK Here is the lucky reading I came up with: bank 1 900v bank 2 890v. At a warm engine idle warming up to 192 degrees or so this is the numbers no trottle up....stf1 0-2.3 ltf 9.7-14.7 Bank 2 few points lower on ltf. Thanks @@ScannerDanner
This is at WOT? Just an FYI, fuel trim numbers are irrelevant when you are at WOT as the oxygen sensors are being ignored.
If these O2 readings you gave me are at WOT, then this means you do NOT have a fuel delivery issue causing your lean condition faults. On to the internal vacuum leak test.
what if you couldn't read the fuel trim numbers on like a obd1 type car ..then it's just trouble shooting ???
yep and water still works on OBD 1 systems :-)
there are many OBD I vehicle that I can view scan data btw
So what happens when you rev it up and your fuel trims increase from like 10% - 28%? Fuel issue?
Fuel delivery issue.
1. Dirty MAF sensor
2. Lower than normal fuel pressure
These would be your top two.
@@ScannerDanner thank you 🙏
don't know if you read comments but got a question. will a low battery/charging system throw off codes for a TCM or abs module.
It would surprise me. Had antitheft issues on a Ford from a week battery. Fix the battery issue first
Wouldnt
So I've been dealing with this car a 95 240sx. I was hoping someone with more experience then me can help out. My cars short term fuel trim is at 99.2 for bank 1 sensor 2. It runs like poop and won't stay on. I put a vacuum gauge on it and it gives me 5 in. If I spray a little bit of brake clean in the throttle body it runs smoother with a higher idle till it dies out because I ran out of cleaner. This is done with the injectors disconnected. Spark has been verified and compression is good. Any insight would be greatly appreciated. I've been battling with this car for the longest time. Thank you. @ScannerDanner
Love your videos by the way I've learned so much and has helped me solve problems in my own cars as well as friends and family. Keep up the good work and thank you for the awesome videos!
It is becoming more and more difficult to answer questions here. I have 80,000 people asking me for help now. So I have created a forum to help you guys better. It is free to join and we can exchange pictures, wiring diagrams and waveforms if needed to help guide you through the process of troubleshooting your vehicle. Thank you so much! Hope to see you there.
Paul Danner (ScannerDanner)
www.scannerdanner.com/forum/post-your-repair-questions-here.html
Paul, Nice !
Why are you getting sparking on the right side of the engine during the first 50 seconds of the video?
you're not seeing sparking, your seeing dust glowing in the sunlight flying past the screen
They're Bishe Sparkles because SD is so awesome. :P
tvtropes.org/pmwiki/pmwiki.php/Main/BishieSparkle
Is the water test safe to do on my VW Diesel engine?
There is no vacuum on a diesel so I do not know
You can hear the big vacuum leak on first startup
I love fuel trims
Is there a way I could send you a waveform and get some feedback
Absolutely. Go to my website and use the forum.
www.scannerdanner.com/forum/post-your-repair-questions-here.html
I got 99% fuel trim for bank 1 sensor 1? O2 sensor?
Are you sure that wasn't for bank 1 sensor 2? This would be a common b.s. piece of data for a downstream O2 sensor as fuel trim is not controlled based on the downstream O2 on most vehicles. If you see 99% on a downstream fuel trim command, ignore it on most vehicles.
@@ScannerDanner thank you love your videos! Short term reads rich -10 long term is lean 15 from top of live data list but under O2 sensor 1 and 2 data 99% fuel trim for both with oscillating voltage s1 and steady voltage s2. When I rev the engine s1 voltage goes to .9v plateaus then drops below .1v. Also spark adv goes 13 to 25 to 0 on a rev. Car chokes at end of rev. Codes are bank 1 rich, low map voltage, secondary air injection low. Car stalls on abrupt deceleration. But cleaning o2 seems to stop this. 2007 saab 9-3 2.0 turbo. 150k miles new ECU injectors, mas sensor, fuel psi good. Original o2 sensors. Is map sensor reading low manifold pressure? Pcv is in manifold stupid. Vented to turbo stupid. Saab story.
Can someone help me find the leak. I don't see it.
You won't see it, you'll hear it. It is the o-ring around the injector assembly in the middle of the intake manifold.
You can see it live, just didn't capture it on video.
In today's electronic world of automotive if there's a problem with the engine the shut off or reduce the gear shift for the transmission these computer modules the PCM ECM ECU what you want are the microprocessors of all these cars they start the car by giving me the relay of ground for the starter for the fuel pump they give a ground the industry has changed but let's keep on promoting on electronics without channels
cool short video
I didn't hear much with the water test. What do you look/listen for?
Just shot one today and actually mentioned you! I couldn't remember who asked the question. I'll have it up in a few weeks. It's a 2005 Ford Taurus so you know what to look for
Sweetness, I'll keep and eye out!
My scan tool has STFT B1 -10.9% but also has STFT B1 S2 99.2% so what's the difference? Anyone?
STFT B1 S1 is your upstream and STFT B1 S2 is your downstream (behind the cat) fuel trim. Most cars DO NOT use the downstream O2 sensor for fuel trim control and the data for the STFT B1S2 is a b.s. piece of data. Ignore it.
Focus on your B1 S1 only
@@ScannerDanner Thanks man that's kind of what I thought but it never moves even .1% and my old scan tool didn't have it!
Yeah, definitely can throw you off the first time you see it.
nice
I love you!!! lol