You have a gift my friend. You have become an invaluable resource for many of us.

I've watched hours of other fuel trim videos on KZfaq which left me super puzzled. Yet you've managed to fully elucidate fuel trims to me in 18 min. Thank you so much. You've done so much for me, my E46, and my wallet. Words can't even convey my gratitude.

wow, I've never seen better explanation of fuel trims than yours, big thanks!

Hey 50'sKid! You are my go-to resource for all things bmw. You're video's are invaluable to me! You have my most sincere gratitude for all the time and energy you put into making these videos that help so many of us. I hope one day to make videos like you that can help people with information and inspire people to help others! So thank you, really, thank you for what you do and all you've given us. Cheers!

Started working on my E46 330Cica recently, when I retired. Your videos have become my source for repair information on the M54. Hope you are doing well!

Man I don't even have any of these problems with my car (knock on wood) but I'm just as grateful to have learnt about fuel trims a term i now know thanks to you. Thanks for taking the time to make all these videos.

man, you bring so much happiness to the life of e46 owners

watched tons of lean code videos, this one is made me understand how those fuel trims work. thank you!

This was the easiest video I’ve watched explaining the way most modern fuel injected computer based cars run. I am so grateful that you are so willing to share your knowledge! This will help me on much more than my e46, I can use this knowledge troubleshooting my other vehicles as well.

your very talented not only with motor mechanics but you explain things very clearly and easily. you have been a huge help, thank you very much sir.

This video just may be what I needed. I've been looking for solutions and this may be the ticket to fixing my car! Kudos to you.

finally clarity, thank you so much for explaining this, best explanation ive seen yet.

Man I don’t know how to thanks for all your knowledge shear with us personally I really appreciate it

I knew nothing of this, but within minutes totally get it from your excellent explanation.

good job man . thanks for explaining all that stuff to me.just got 330 ci and everything needs to be changed .

Hi, great bravo from France ! You speak very clearly and your are very good at explaining stuff, your video have helped me a lot with my E46. Keep up the good work!

Hello mate, brilliant videos, thanks for all the explanations and example. I've got a 2001, 316Ti (the liftback ones) with the N42 engine (I know, 1.8l, small, blah blah...) and I've been using these bluetooth OBD2 reader and the Torque app on my phone, which has already helped me out a few times. Recently after every (relatively) cold start, the acceleration of the car suffers a lot and it makes a muffled noise as if it's overfuelling or chocked. This continues throughout the warmup and usually doesn't go away on its own until i turn off the engine and switch it back on, at which point it works as if nothing happened. After seeing this video, I've configured the app to read short and long term fuel trims on all sensors and what I've noticed is that after a cold start, the short term fuel trim goes crazy and fluctuates from around +8 to -8 all the time even once the engine warmed up, but after shutting it down and restarting it, it all smooths out nicely. Any idea of what might be going on please?

Very informative I have exactly these fuel trim diagnostic codes and will now follow your instructions thanks a lot ..

Great Video (As Always), You do have the art to deliver information in a good and comprehensive way people can understand. Thank you. Can't wait to see the video on how to replace that fuel regulator.On another note, Can you make a video dedicated to the Vehicle interphase and the software you use?I've been meaning to acquire one of each but not convinced on which way to go on terms of hardware and software.Take Care and keep up the GREAT work!

I have M54B30 with strange fuel trims. I checked fuel filter which was 12 years old. I still cant believe it! but this solved my trims on both banks! Amazing!

Thank you man, I solved my problem thanks to you and now my car passed the smog test.. You really know a lot!!!

Thanks, really great M54 diagnosting. Great video and keep up good work.

hi , i am a bit late 4 years but this is the best tutorial on fuel trims.

this is awesome! I've been chasing fuel trim problems on my e46 for over a year now. Thanks!

Very good video easy to understand i am no longer puzzled about fuel trims.

You're God sent. Thank you for all your hard work.

Thank you very much I really like your channel and from this video i realized i had to delete the adaptations because my short term fuel trim are +1 but my long term fuel trim are -4 and maybe then I'll figure out what the true values are.

Love the internet. Thanks for sharing and explaining so well. I'm gonna have a look at my fuel trim.

Thank you. I'm still getting to grips with the software but mine was #2. Dirty MAF. Replaced and 200 miles so far so good 🙂

Thanks a bunch. Quite detailed and compehensive stuff!

Hey great video's, I've been chasing high LTFT for a while. I"ve replaced pre-cat O2 sensors, CCV system, fuel pump, fuel filter, both intake boots, IAC boot, rebuilt the DISA valve, replaced the Brake master cylinder vacuum hose, the tee that connects to the boot, checked all vacuum lines. I've cleaned the MAF sensor. The STFT will hanging around 0, but the LTFT still reads around 11. I finally replaced the MAF sensor and It corrected the problem. After about a 30 min drive , STFT was reading around 2 and long LTFT fell to 0. My car is an 06 325ci vert with 112k miles. So it seems that the old MAF was not correctly reading the amount of air entering the engine, so it looked like a vacuum leak / lean condition but in accuality it was a faulty MAF sensor not measuring the correct amount of air entering the engine. I guess the most puzzling thing was the car ran and idled good and smooth.

This is so helpful. I've been trying to figure out the cause of my rough idle.

Sir you are great , excellent videos very easy to understand I watch you from Mexico and just change my Thermostat without the locking tool ... You are saving me a lot of pesos !!!

Superb video. Well explained and answered all the questions I had.

thanks for a great video. very informative i was able to figure out what this issue was with my bmw 330i. I replaced the reg/filter and that solved the codes.

Brilliant video and information! Glad I came across this.

This video was on point, very helpful enjoyed watching Thanks man!!

Thank you so much. Absolutely great video. Easy and cool presentation. Keep it up

Thanks 50’s Kid! Will take a look tomorrow to see my trims from those lean codes.

Thanks a lot! Keep posting about E46.

Great video you help us all a lot, I don’t know if you’ve had this vacuum leak, took me a while to find it, it was underneath the bolt holes on the rocker cover, very very small cracks underneath the rubber seals, just one to look out for boys & girls👍

Excellent fuel trim Tutorial

Hello everyone, I have an 02 325ci and got some codes. Currently swapped my maf sensor, last week swapped the ccv system and valve gasket. Realized I have a small oil leak under the oil pan gasket as well. I am still getting codes p0171, p0183 and p0185. I hope to figure this out on my own but just want to say thank you so much for these treasure videos.

Absolutely great video! Very helpful thank you.

Very informative and well delivered. Thanks!

EFI basics with a bandana! You're good at this.

I’m sure you heard this before but THANK MAN!!! If your ever out east come to the Hamptons We’ll smoke a bowl!!!!

Learned so much from you! Thank you!

Excellent job.

Very nice explanation. Thank you

You my friend are a genius! Just bought the obd and software für my M54B30. Thanks a lot! By the way... Many ELM 327 china chips are Bad copys and the software can have a virus. Be ware

Excellent job, thanks

great video! 1st i had an emissions code so i replaced the rear bumper valve at canister. code goes away. then, immediately i get a vacuum leak code. ends up being the oil return at dipstick tube. replace hose and code goes away. then, all of a sudden 420/430 pops up together immediately and now i can not get rid of those codes. car drives great and does not lack power. reach 30-35mpgs (highway) when being delicate on the throttle. so it's very hard for me to think both cats are bad. '05 330i zhp 6spd this video gives me something new to check out. thank you

Dude awesome videos!

GREAT video(s)!!!! Thanks!

50sKid Hi, so I worked out the 28B8 problem. Took off the exhaust solenoid again and felt the piston that the solenoid drives... it was frozen. Carefully removed, cleaned the piston and cylinder area, reinstalled... ran perfect, no more codes.Thanks Bob Campbell

Thanks a bunch been tracking my P0171 P0174 issues found found the trim levels to be 27% sounds like a massive vacuum leak thanks again!

Very good job, 5 stars

Great video!

VALUABLE info here. Thanks!!!

Great video bro!!!!

Great video bro...

Thanks Dude for keeping it real! Good info and very knowledgeable! Sounds like you have years of experience. BMW trained?

you are the man

Thanks

Great ..Thanks

Thank you very much

Very good video

Great tutorial, thank you. :-)

superb

Most helpful videos on KZfaq! I'm going to test as per your video as I have the same issues on my 2002 330Ci I recently bought, however there's one thing I was wondering about: previous owner had a CCV delete and I can see the dipstick and intake ports for the CCV are closed while the breather is venting to the atmosphere, in such scenario I don't think you'd have a significant vacuum leak since the intake ports are closed, correct?

My fuel trims were erratic with the scan tool. I had no vacuum leaks. I had 0171/0174 codes. I replaced both upstream O2 sensors and it is now completely stable. Bosch O2 sensors only have a 100,000 mile life span I found out.

Thank you so much ⭐⭐⭐⭐⭐

my P0171 on sentra is impossible to fix. 4 months of testing replacing parts and still problem.only on youtube is always cracked intake boot....wish you had graphed the MAF sensor when you created that vacum leak.good film TU.

Really informative video man! If anyone knows, should I perform the same fuel pressure test on my '99 528i if my STFT increases under 2500 - 3000 rpm? STFT is within range at idle. MAF has been replaced within recent history as well.

Damn that was bad ass!!!

Could you do a video on how to set up the hardware and software. How much should i pay for the Program? What features should I look for when purchasing the ELM adapter? Thanks!

First, Love the videos, thanks! I've watched most of them even though I don't have most of the issues you are having, it is good to know these things and you cover them well. So I'm going nuts here. My fuel trims are 20+ when in Open Loop, with a misfire on various cylinders. Once the ECU transitions to closed loop (warmed up) the misfire goes away and idle smooths out (not perfect, but pretty darn close). Fuel trims drop to around 6. I have pending lean codes as well as misfires (random) on 5 of 6 pots. When RPM rises fuel trim approaches zero regardless of Open or Closed loop. So I'm sure I have a vacuum leak, but why would things get better when the car warms up? I've replaced the DISA O-Ring, secondary air pump hose, upper intake hose (lower is on the way) and checked other issues. I don't suspect CCV but that my be wishful thinking (no smoke, no excessive oil consumption, vacuum on oil fill cap not excessive. arrggghhh

Helped! Subscribed*

Thank you. does it matter which version?

My lt fuel trim is negative 5.5 short term bounces from 14-22 positive both banks unplug maf drops down to -1/4 new disa clean maf and car is in limb mode

Have a ? I own a 2004 z4 2.5 I changed the ccv I disconnected the battery before I started and color coded the plugs so I wouldn't mix them up even tho they will only fit the right one but after I hooked the battery back up after completing the job and now it will crank but won't start any idea

Great video! I need help with my bmw 550i n63 Engine. I do have catless downpipes but it smokes a lot and it exhaust smell coming in the cabin. My fuel trims are negative and been so even prior to catless downpipes. I get codes p2196 and p2198 and fuel trims are -3 and -1.8. So far not sure if a vacuum or pump. Don’t know where to begin. Shops here are clueless

Hope you will see this. I had fuel trim on bank2 of my m73 up to 20%, did your tests and found out its a vacuum leak(I sort can hear it). But I fixed the fuel trim issue when I removed the Air Injection valve it went to almost perfect 0%. Why is the air injection valve causing a fuel trim of 20%?

Hey man, that's such an informative video and a great way for diagnosing the fuel trim bank 1/2 issue .. I'm facing the exact thing and I'm going to try this method to figure out the issue. My E46 330Ci is a japanese import and almost no OBD tool is working with it, I just purchased a BMW Scanner and hopefully receiving it soon .. Can I do the tests using the BMW scanner and its software?

This is a great video. Very clear and informative. Once I've got this software, hopefully it should give me some confirmation as to why my car is sluggish at low revs. Many thanks for taking the time to make this video.

Great video, very instructive but your engine still sound funny at 14:16 some kind of ticking and wobbling, maybe a pulley is bad ...

How would you go about diagnosing if the long term fuel trim is high? I have an '03 Z4 that had a DISA leak and torn intake elbow, and its long term fuel trims are 11%. Assuming if it's all fixed the short term fuel trims would be -11%, indicating the short and long term would cancel out? Or should I reset the DME and start from scratch? Thank you!!

hello Jason recently replaced ccv all vaccuum hoses on my 04 330ci rebuilt disa with g.a.s. kit. the service engine soon light is still on disconnected batt still is on do i need to erase the codes in order to reset the light. codes show bank1 bank2 lean also shows replace pvc valve which i have already done.your videos and your help is greatly appreciated.

Hey kid, love all your vids...have def used more than one for some DIY. I have a p0174 lean code on 2003 330i. My STFT on both banks are ar 6/7% and mt LTFT are at 11.7% at time of code. I was at 73mph when the code was thrown. I feel a slight hesitation at around this speed. I've had the car checked for vacumn leaks and have replaced the usual suspects. Just replaced the fuel filter. This car hasn't had the fuel pump changed or MAF as far as the records show. Any help is appreciated...ty

I have a 2006 bmw 330i just changed both mass air valves and sensor and my car still runs rich till it dies but will start right up but smells like it’s running rich

Would a maf sensor problem cause multiplicative adaptions of 12% but nothing on additive adaptations? CA & CB Fuel trim bank 1&2 control limit but no P0171 code?

Why you need to take out the fuse and let the ignition die? Did you plug the fuse back when using the fuel pressure gauge? Please explain. Thank you

You solved the problem í have a bmw325i 2003 with the same problem fuel trim bank 1 and 2 that must change?

Very informative, I now completly understand how the fuel trims work now. Dude seriously, are you a teacher or professor in your day job?

I’m a little confused at the MAF part. What constitutes a good/working MAF? Does it have to read a certain amount of airflow at idle. I unplugged mine, engine didn’t stumble and the ST fuel trims stayed positive and didn’t drop suddenly negative. I have a similar engine, not sure if it works same as your example 2006 X3 with the M54B52 motor.

thanks again for this great video and a very well explainable finally someone that knows exactly how to explain fuel trims and diagnosing it. I have a problem with my BMW X5 3.0si 52 engine. can a vacuum leak cause misfires I did a diagnostic analyze data and it shows that my short-term fuel trims are 29.9 on both Bank 1 and bank 2 but I am also having misfires can this cause it and also the error leak is coming from the variable motor gasket should I replace the whole entire valve cover

Really good video and explanation of the process and diagnostics.

I've just replaced my fuel pump regulator to get rid of negative trims, but the trims are now biased positive - will they come back to normal with a bit of driving, or do I need to do a reset? If the latter, how would I do it? All I've got is an OBD code reader...

Hey so my fuel trims on my e46 are 25% on both banks and today at a red light the car started shaking really bad and when I started driving the higher the Rpms go the more it was shaking and when coming to another red light I pressed in the clutch and the rpms dropped all the way to 0 and the car died. When I turned it back on it was back to normal and didn’t shake or die anymore but the fuel trims are still at 25%. I have the check engine light for the lean codes you mentioned in the video. Any idea on why the car would shake and die and then go back to normal?