E46 Negative Fuel Trims Case Study
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- เผยแพร่เมื่อ 28 ส.ค. 2024
- This 1999 328i would not set it's catalytic converter engine monitor for over a year. There were no DTC codes thrown. This was my process in diagnosing and repairing this problem.
This video is for entertainment purposes only. 50sKid assumes no liability for any repairs or modifications performed by the viewer as a result of the information contained in this video.
Love your videos and love how you don't chop out the misleaders. I like that you follow every step and show us what your doing in detail. Its great to be able to compare your findings with my own. Thanks 50's kid!
Thanks for posting the missed diagnosis as well... A real professor!
Hello 50sKid,
Very nice and detailed video. You are very detailed in your approach to diagnosis and I learn much about the BMW engines.
As for fuel pressure issue, and checking against five regulators, I would suspect the gauge. To often people believe a poorly calibrated gauge as accurate and it will severally bias actual world conditions of measurement......Yes I am also a QA guy and experience this situation too many times (trusting a bad/out-of-spec) gauge.
Thanks again for your videos,
P
distracted or not, what a great tutorial you have uploaded fella, jam packed with knowledge, thank you so so much..
Great video. I really appreciate the thought process explanations.
That was one great success. In my opinion, not so easy to resolve. I have to try this scanmaster for livedata.
Keep up good work and keep E46 on the road, those are great cars.
Very good video. As a suggestion, I think it is a good idea to reset adaptation every time you modify something, for example the O2 sensors or a change in fuel pressure due to a FPR. You save time in that adaptation. I´m working on a 99 328i E46 with negative fuel trims as well.
Great video. I have a 1.8 Vauxhall.never thought of changing o2 sensors in pairs. But food for thought. The scan data graph being on a pc was alot larger and clearer and great I could the difference in bank 2. Well done and thanks
What a journey!! Thank you for sharing this case study. Lesson learned.
Straight to the point! Thank you not too much talking like other channels. Great explanation
Great video; really fantastic diagnostic skills displayed here.
Finally I understand Negative and positive fuel trims. also the O2 Sensors data. I just got the Scanmaster sw I will give my data a look. Thanks Kid
Wish I could give you all the likes and subscriptions in the world. You're a definition of passion. Thank you for the massive info volume.
nice tutorial, the best so far, and i've watched almost 50 videos on this subject.
Come on man....with any issue with fuel trims, first step should ALWAYS be to monitor what o2s are doing and simulate a rich/lean condition to see if o2s respond properly. Wasted so much time by pulling injectors and swapping not just one fpr, but 5. I recommend subscribing to scannerdanner premium and buying his engine performance book.
Exactly!!!! Monitor LTFTs, STFTs, as well as HO2 upstream sensor(s). Actually, they are "reactors" more than they are sensors.
how do you do that? to get rich you turn the MAF of? and to get lean, you take of the ccv hose that goes to the valve cover?
@@komentatorius69 i have used a unlit propane torch with a hose on the nozzle to a vaccum nipple to simulate a rich condition. To try and simulate a lean condition i have pulled the brake booster hose off the intake manifold to allow un metered air into the engine.
Not sure if these are the correct ways. Try at your own risk. I'm not responsible if you mess up your car or injure yourself or others in any way.
Sorry man for the fact that I am allowed to give you only one like, you deserve absolutely a lot more.
Ur absolutely right at 3:20. Cant put cheap aftermarket stuff on bmws. When i bought my car it had some cheap aip electronics maf on it and i spent 6-7 months off n on trying to figure out the fuel trims being maxed at like -25%. One day i just happened to be checking the intake tubing and i saw the lil ghetto resister in the maf in place of the element. Switched it out and issue was actually positive trims
Yep! Very common, you just gotta be careful about what cheap parts you use.
Only switching oxygen sensor is problem. Great information
Great video, very organized and to the point, I'm subscribed, keep it up man!
This is an awesome diagnosis step ny step why negative fuel trims. What would you do differently to get hete earlier? GREAT VIDEO. DONT COMMENT MUCH BUT GREAT WORK!!@@@
Yet another great video! Many thanks.
Thank you for your time
Thanks for sharing the video with us.
GREAT video! Packed with lessons
I had a similar problem. I replaced the pre and after cat sensor, fixed everything.
Thanks 50's your video save my money time and from useles jobs, after engine swap we connect wrong lamdas 😀💪👍
appreciate for your great info, it really help me a lot.
Thank you, very useful, I have something similar, have clues what to check
Thanks for this buddy still very useful video
Why were you unplugging and switching O2 sensors for the front sensors but you were talking about the rear sensor?
Hey 50sKid, love your channel! Question: what's the likely scenario when the long term fuel trims are at negative 8 percent, but short term fuel trim is near 0? That's the situation I have and I'll double-check I have a Siemens Mafs, but curious if the Mafs would cause it for the long-term fuel trims. Thanks for any help!
MAF is a possibility. Also bad 02 sensors. Bad fuel pressure regulator (check if fuel pressure is higher than 50). Do the fuel trims get more positive when the RPM is at 3000?
I'll have to run the live data on my scanner next time I get a chance, unfortunately I'm still new to looking at live data. It's also been a long time since I did the fuel pressure test, so I might have to do that again to know, because I don't remember if it was higher than 50 or not. O2 sensors are fairly new, so I think you can rule them out. However, when I was looking at the freeze frame data, both long term and short term fuel trims were in the negative, around negative 8-10. So the car is running rich and the ecu is compensating right?
Fuel trims look good, ZoommaiR. Normal
You are slightly rich. Short term should move toward positive on the long term (less negative ) if ECU is compensating. After about 30 seconds to a minute.
Great success!
Negative trims means
1. over-fuelling - fuel pressure too high, leaky injector/s,
2. under-burning - weak coil/s, fouled or faulty plug/s, or
3. air intake blockage (not likely)
I have to watch the video the second time and I'm still having the same kind of problem
I want to understand one thing.
So if you drive long time with a broken o2 sensor the engine wil adapt and make new settings. I have a bad o2 sensor after cat. Engine runs rich. I have cold start problems because long term fuel is -100% . And both short term are -60 while idle. When throttle they went up to -90.
So the bad starting cold is due bad o2 sensor?
Awesome video love the detail
You did great job.
Hi this soft sanmastrer is free? Full version?
When i add fuel, the fuel gauge needle does not move up immediately, just slow as i drive. What could be the issue?
what did u use to do the live scan ? I belive u used a laptop, is that something anyone can get or is it only license mechanics that can get it? Your videos are very helpful. thanks ....
The hardware is ELM327 cable from eBay (it's a buggy knockoff that drives me crazy because it doesn't always work). The software is Scanmaster ELM.
I have a Autel MD802 Scanner that suppose to transfer data to a lap top! I have not tried it yet to see haoe well it works. If you purchase this model it will do live data. I paid about $260.00 Cdn at Amazon Canada. i did a lot of research. If you want this type of function. You will need to pay more. By the way Banda this scanner will also diagnose tranmissions. The more you pay the more it does. This is a technician grade intrument. You will need to spend a lot of hours learning how to use it. So far I like what I see. Sofware is live time and is free. It covers many Asian, Eropean, domestic cars. I hope this helps you!
HI 50s kid great video, what would be the likely cause of very high lean condition (25 for both banks short term from cold) and after 20 mins of driving the bank 1 drops to normal levels whereas the bank 2 remains at 25, should i be looking at 02 sensor voltage output? Thanks
It’s the opposite actually. If it’s a bad maf your fuel trim will continue to go down while engine rpm increase.
Bad MAF at normal speed will under estimate the air entering, as expected by the TPS and ECU. Thus mixture will turn out to be lean because of more actual air, causing an increase in fuel input. However I guess the MAP would then record a higher air pressure than assumed by they same TPS and also make additional adjustment via ECU. I always wonder if the Fuel Trim reading is the Sum of all the adjustments made in the ECU (MAP MAF 02), or just the O2 sensor result. I would think the Fuel Trim figure would have to be the Net result of all the ECU adjustments from input from the MAF MAP and 02, since it is meant to be indicating the net fuel increase/decrease over the mean.
Could have done the fuel pressure leak down test with injectors in place or am I missing something?
Can you tell me what software are you using?
Mine is difficult to start it takes about 5 seconds of cranking and it stinks like unburnt fuel I’ve got 0 codes but my fuel trims are off and I simply just can’t get to the bottom of it very frustrating
Hello sir, love your videos and have been a sub since day 1.
Had a question for you. I have a bmw z3 with lean codes. Car has extensive service history. Had it for 12 years.
To diagnose the problem i smoked it, no leaks.
I watched your video on fuel trims and my situation is very odd.
Trouble codes are p071 p074-lean bank 1 and 2.
Short term FT are -6/-7 for bank 1 and 2
Long term fuel trims are 11.7 for both banks. And they stay 11.7 with rpm at 2.5k.
Interesting thing is short term fuel trims go up to + 7 with rpms going up to 2.5k
O2 sensors. I’m getting normal reading for both bank 1 pre and post cat sensors.
Bank 2 o2 sensors stay at .8 value.
I’m really confused.
I did order maf cleaner and fuel pressure tester. What should I check next. What do you think is the culprit here?
Thank you!
Very useful thank you
hello. SHRTFT1(%) = +6.3 and LONGFT1(%) = -7.0 , is good or bad?
Another question: SHRTFTB1S1(%) = 2.3 and SHRTFTB1S2(%) = -100.0, is good or bad?
what does "G"?
Environmental conditions affect fuel trims especially warm and humid temps will give negative fuel trims
what software are you using??
Hello bro, I have problem.. black spark plugs, high fuel consumption, my long term fuel trim is negative -18%, I cant found problem, injectors new, I I tried another maf, o2 sensors. My car is bmw f10 2011m 535i witht n55 engine. Maybe you will face such trouble? No errors.. smoke test done, I checked and cleaned vanos solenoids, install new oem spark plugs etc. Thanks for your advice bro:)
what software on your computer are you using for this Case study
And can a bad fuel pressure regulator only affect one bank thnks in advance
Bro on part 3:20 of this video could that just affect 1 bank if it's a v6 engine like could an aftermarket MAF sensor cause -50 short term fuel trims on Bank1 and on Bank2 at (0)
Hey man can you help me? I had a cold intake down to the bottom and it was raining for a day here in California, no longer have the weather guard by the tire. Well, the filter got wet and as i was driving home from work the car kept losing power and wanting to die out, the car died but started back up and i proceed to go slowly home. i made it home and let it sat for a day and convert back to a short ram intake. But now it car feels sluggish and once i get to 5k rpm the power cuts out. I plug in my scanner to check short fuel trims. once I get to 5k the power cuts out. It shows -17 Short term. So, what that means is its running rich and is taking too much fuel out right since its 17- and that's when I lose power. I did have a check engine light for a EVAP Canister Purge Control Valve leak before, but it was fine
I have -10 for my fuel trims at 2000 rpm and 0 at idling, what can it be ?
Good evening I have a 05 E46 that I get a p1500 code that sets. I have replaced the idle speed control valve, the ccv system and intake boots due to being torn. But I can not figure this code out. All my fuel trims are negative in the freeze frame data any help would be greatly appreciated thank you
Moral of the story - don’t let an idiot work on your car.
Hi 50s Kid. 03 325ci ebay headers with 90 degree o2 bung extenders.
Code P2098. Have RPM surges and drops during acceleration between 2500-3k and 3500-4k
Also throws P0171, P0313, P1093...
freeze frame data =
load value = 31.76%
RPM: 2389
Short Trim fuel % bank 1: -17.97%
Long Trim fuel % bank 1: 1.56%
Short Trim fuel % bank 2: -8.59%
Long Trim fuel % bank 2: 1.56%
Unsure if fuel related or VANOS?
No known vac leaks, sprayed carb cleaner all over intake area.
what are the trims idle?
50sKid how would I go about checking the trims in OBD fusion at idle?
I cleared the p2098 and it came back with a different code (misfire with low fuel)
Freeze frame data this time was
Short term bank 1 - 7.03%
Long term bank 1- 1.56%
Short term bank 2- 1.56%
Long term bank 2 - 2.34%
(2584rpm, load value 16.86%)
Second code was p0313
You do realize you couldve just pulled the vacuum line on the regulator and observerd fuel pressure gauge for changes
These engines work on constant fuel pressure. It's not a vacuum line but a vent line so in case of diaphragm failure the leaking fuel would have somewhere to go. If he pulled that line nothing would have changed.
My car reads in INPA, lambdaintegrator 1 -25%, and lambdaintegrator 2 +26%. Do you have a clue? Thank you Sr.
Sounds like a vacuum leak. Why was the LTFTs at 0%? It should have stayed high until it learned the fix.
Hi
Nice vid... What scan tool do you use?
does replacing the battery reset the Cat Monitor fuel trims are sightlynegative .1-.2 % and the MAF reads 4.7 g/s and car runs fine will the cat mpnitor go off after a long drive? Thanks I love your videos.
Hi I have a Q!
Honda pilot 2003 3.5
Negative fuel trim issue.
I have only 2 sensors for both banks.
My problem is on bank #1 pcm shutt down this bank completely
Both sensors are reporting Short term -27.3%
S1. Fluctuations 0.940V. 0.630V. I think is rich.
S2. 0.035V. 0.140V mostly stayed 0.035V I think is lean.
But bank 2 is working normally can't tell the reading my scanner
Don't shows.
But the evidence on spark plugs are visible.
And on bank #2 you disconnect each wires from coils and they miss.
On bank #1 don't.
But if I disconnect bank #2 completely.
Then pcm put #1 bank to work...
This is weird!!!!
Can you help me on this please??
Any Advice???
Take your time but please answer !!!
Thank's
I got a Buick enclave and I have negative 100 on bank 2 for both short term and long term trim. O2 sensors and fuel pressure is good.
I also have no codes and bank 1 tests very good..any thoughts , cheers
Hello 50'sKid...I have three codes right now which are Po17,Po172 & P0041. After watching this video, my question is could that be my problem??? I just had those same two O2 sensers replaced a few weeks ago. I drove to cycle the code out, and it cleared. I then replaced the OE lower and upper intake boots, and the MAF(aftermarket). All codes cleared, drive seems back to normal, then all of a sudden I get the three codes. P0172,P0175, & P0041....NEED HELP ASAP TO TRY AND FIX THIS PROBLEM. Do you think the O2's were maby plugged in wrong?HELPHELPPLEASE THANKS
It is strange that long term fuel trim is 0, at the start of the video. That can indicate that you have a problem with fuel sistem.
And when you switch places on rear bank O2 sensor it starts to work as it should, and they corrected long term fuel trim to -3.
I also have LTFT fixed zero, and trying to find the solution. Unfortunately i have one pre cat and one after cat O2 sensor, and they are connected as they should.
My car has 0 for LTFT, and i am searching for the solution.
Ana idea where to start?
zdravim mam oblem z 530 d e39 toči jen 2900 otaček vic ne kde mam hledat problem
No engine light 03 sonato
Live read negative fuel trim. -2.3. Long term short term 0 at idle
Engine shakey some time like it want to turn off
Great video man. Have learned and done a lot to my 330xi from just watching your videos.
This whole fuel trim thing is new for me, and trying to figure out my fuel trim issues. The STFT on both bank 1 and 2 average 3%-5% at idle but drop to -3%-0% as I increase rpms. LTFT are constantly at 7%-8%.
Im throwing a P0491 and P0492 so I know my secondary air needs some attention somewhere. Any thoughts?
Concentrate on the secondary air system. I'll bet the vacuum line to the secondary air valve is broken. Check that out.
Do you have a a shop service manual? That may help you......Hope that helps
What were the symptoms ?
Fuel pressure I the same 54psi before and 54psi after!?!?
I got a 98 528i and I was working on the fuel filter and somehow I broke a plastic pc of the pressure regulator valve and it’s kinda too expensive to buy a whole new one is there any other solution for itt like if the spectre ones I can work with?
I do have a long term fuel trim of -7% on e46 m3. When i rev it up to 2000rpms steady. my short term back goes to -22% and my car starts stuttering. This is not evident when im driving underload or WOT. Short term bank stays between - +5% on idle and while driving. Only under steady rpm with car not moving it jumps -22% and stutters. Any idea what this could be? I have been trying to figure this out for awhile now.
What does Alldata tell you about fuel pressure.
Hi 50s kid , really good videos i tried to find out a fix for my car BMW 3 series but cant find any issue , please sir if you could advise me . I had an OBD trouble code which is ( P1168 Post Catalyst Fuel Trim System Correction Value above Threshold (Bank 1) .
Best regards
good morning 50 skit Klim thank you again for helping us and explaining well how to deal with our cars you mentioned on this video that you have to replace oxygen sensors in pair since my X5 2008 3.0 has 4 oxygen sensor do I need to replace Bank 1 and bank 2 Upstream in pair or do I have to replace one oxygen sensor from bank one and then one oxygen sensor from bang 2 I'm a bit confuse and thanks again.
I mean bank 1 and bank 2, either front sensors or back sensors.
50sKid thanks so much..
I have civic 2005 1.5L. It does not have O2 sensor. On OBD2 it does not support STFT/LTFT. How this works in my car?
You would think BMW would make the wiring to each sensor different lengths so that the sensors couldn't be inadvertently switched.
Hey i love your videos and your work, keep it up. I live in the UK and i got an e46 2003 325ci msport auto. Now im getting fuel trim bank 1 and bank 2 permissible range exceeded and fuel trim bank 1 and 2 control limit. I have no vacuum leak, i replaced the top 2 o2 sensors for bosh ones, i replaced the maf sensor for non oem ( völt) brand. The car would have rough idle when the codes do show up, sometimes it would even cut out when approaching a junction or teaffic lights, and when i go from neutral to drive or reverse the revs would go bellow 500rpm for a second and go back up to where it should be. Any thoughts?
I'm sure you have now figured it out. This is a classic symptom of a failing camshaft sensor.
Please help can't figure this one out I have code saying running rich Bank 1 and 2 however Downstream I'm getting an absolute no reading on the fuel trim and negative fuel trim Upstream
ONE THING that is bothering in mind that when the Long term fuel trim is already coming in NEGATIVE it means the ECM is cutting the Fuel that much percent , OK understood but when the FUEL is cut already that much percent WHY still it is showing in negative ? it should be to ZERO around bcz the excess fuel is already CUT . why it is always showing negative ? no sense i think . what you say . ?
The e46 G.O.A.T.
My fuel,pressure regulator doesnt have that small nozzle that you pointed at in this vid )aftermarket( is that ok?
6:35 I didn't see no fuel pressure being lower!!! 😬
hi
my car Reports negative ten long term fuel trim ONLY AT IDLE as I push gas pedal little bit like 1200 rpm or 1500 rpm the long term fuel trim comes to negative 3 or less immediately ! any one can tell me why it shows negative ten at idle only?
Hi, can you tell me where i can order pressure gauge, what does fit in m54 fuel line Schrader valve
How does the scan master talk to the car ,do you get a blue tooth dongle or something?
How did you take off the injectors?
I take it you are talking about the Readiness Check.
Hei,i have on long fuel trim 3.2% and on short its jumping fom 0% to +- 5% and all monitoring i have complete. is that i sholud wonder about? thanks fore answer. Engine M54
Very normal readings, Tomas.
Great video 50 thank you I'm really digging you PC based scan tool. Where? How much? Take care man
The hardware is ELM327 cable from eBay (it's a buggy knockoff that drives me crazy because it doesn't always work). The software is Scanmaster ELM.
Hello, I'm having a weird issue, my bank 1 short term is between -100% and -90% at idle, when going 5k rpm it drops to -50%. Only on bank 1. Long terms are both on -6.3%. When opening the oil cap, short bank 2 goes up while the bank 1 doesn't move. Does anyone have an idea?
Thanks !
Hey, I have recently bought a 316i e46 (N42B18 engine) and I've got some problems with the oxygen sensors... Currently the oxygen sensors are swapped (according to realoem) but if you swap them to their correct positions I end up with a fault code saying they are swapped. Disconnecting the bank 2 cable gives a fault code saying that the bank 2 sensor is disconnected.
Any help would be greatly appreciated!
Ps. I've learned a tonne from your videos and I watch them like a teenage girl watches Netflix.
hey quick question... 02 325i do u think my car would run rough if I remove the stock air box and install a aftermarket cold air intake ? thanks for answering my questions..
usually that isn't a problem, unless it's an exceptionally bad aftermarket product and the engine can't breath as well as before.
+50sKid ok thank you very much for replying.
Sweet video bro!!!!!
Ha - I was thinking all through the diagnosis how working on a two-bank system would make it easier to look for discrepancies...but only a two-bank system could have the swapped leads problem!
Definitely helps to have an extra sensor to swap over. Or fuel injectors to swap from bank to bank
Hi mate, I saw this helpful video 100 times, and I was read all e46fanatics thread that you talking about. I have 328i 99 too. But is not conclusion at the "idea" of no vacuum in the FPR. What is you conclusion about it?
My 328i has FPR in the top of the injection rail, so is like a 323i. I suppose it was the first configuration of BMW for this early E46's.
Something is picking my mind about all this.. I recently was forced to replace fuel pump and fuel filter, I was follow my LTFT/STFT all the time before this changes and Im was always negative LTFT (-7 Bk1 / -3 BK2). Now, with those changes still negative (but less)
O2 pre cat are new, sparks new, MAF +/- 3.8 g/s at idle, FPR 1 year old. all the fuel sys are new.
Rail pressure at idle is 57 PSI.(more than 54 psi spec.)
So.. is the negative LTFT related to the over pressure on the rail?
If all elements on my fuel system are new.. and this is my picture.. how can I tuning the rail pressure.?
What about the idea of FPR regulated by CCV?
I know, a lot of questions.. but please, put some light on it.
Thanks in advance.
My guess 2 or 3 lbs, difference in fuel pressure will make no difference at all. I mean zero. Three lbs more is about 5%.
I tend to agree that the likely cause of seemingly
high idle fuel pressure is lack of the vacuum signal to the FPR. It regulates based on the
pressure differential in the intake, so at idle the intake is at partial vacuum and the FPR will reduce the pressure to maintain 3.5 bar across the injectors.
Rear o2 sensors represent what happens inside the converter who's job is to store and release oxygen