Understanding the basics about fuel trims

[@DallasAutoDiag]

After many many videos I have watched on fuel trims I never thought someone will come with a new approach. I think using the rc car is the best example I have ever seen on fuel trim. Well done. 👍

[@BrianMann216]

Thanks for the compliment, I learn by analogies myself and have been looking at ways to get the point across for those that want to learn.

[@Jedi_Masteren]

One of the best presentations ever seen, but I missed one definition from you, to give a full picture, that's the definition of closed and open loop. What does that mean? How does it interfere on the fuel trim? 🤔

[@fredsalter1915]

Subbed. This video is gold. Outstanding practical demonstration!!!

[@JaymzMhart]

@@Jedi_MasterenOpen loop is when the computer ignores feedback from sensors and uses last known data to run the engine until it warms up. When it’s ready, it will go into closed loop mode and utilize sensor data to make needed changes to stay running smoothly. From that point on until shut off, it remains in closed loop mode.

[@cool_katt6652]

Let me ask so You add the short fuel trims nd the long fuel trims so what the reason of adding both , The total sum??

[@Elgallazo29]

You are the best of the best. I hope that most of the "auto mechanics"here in California start watching your videos so they can learn something about fuel trims

[@ricardoviana5059]

a decade looking for avideo like this. just can't thank you enough.

[@konyoha]

I just found out that fuel pump pressure has a big influence on short trim and fuel trim correction. The lesson you gave really helped me understand this. Thank you

[@Steven3873]

The best "show and tell" tutorial on fuel trim I have seen, you definitely do not have to be an engineer to understand this. Thank you for taking out time to help on this.

[@BrianMann216]

Thanks for the comment and for watching!!

[@denzelw9664]

I wonder which institution you teach at. Without formal training I have tried to understand fuel trim through others but not everyone is possessed with the gift of imparting knowledge. You possess that ability and does so with ease. You can only explain something if you truly understand how is operates and you do. This have brought me to a better place and a better understanding of how fuel trim works. Thanks man keep up the good work. 👏

[@BrianMann216]

Glad I could help!

[@tomwinslow5086]

Im a diy guy. Thank you so much for making this so clear and simple. I will be watching more of your videos.

[@mikemorrow6736]

Extremely well presented. This video answers a multitude of questions concerning fuel trims. Using generic data to view fuel trims is not included in any diagnostic scanner's instructions. I have been plagued with trying to read fuel trims on Nissans for some time now. Thank you!👍

[@BrianMann216]

Thanks for the comment!

[@meblake7359]

That was an awesome demonstration of fuel trims. Thank you.

[@dlouque]

Very good explanation for this old school mechanic starting out working on my own vehicles again. My son tried explaining it to me but you explained it better. Thanks

[@jacksonmusyoka1216]

Have been very much interested in understanding fuel trims and after watching this I can now say I've got the point I've been missing thanks. This is my first time in this channel and i like it.

[@BrianMann216]

Thanks for watching, please subscribe if you have not! I have been working hard on good diagnostic content!

[@jaredadams5194]

This was definitely the best fuel trim video I have ever seen. I am having a problem with a P0401 code and fuel trims around -12 to -16. Very informative!

[@BrianMann216]

Thanks for watching

[@jaredadams5194]

@konstantintrehagyrevopoulo972 I put on a new EGR valve, DPFE sensor w/new hoses, new EGR tube, and EGR vacuum solenoid.

[@jaredadams5194]

@konstantintrehagyrevopoulo972 still doing it...plus, it has a code for Rich on Bank 2.

[@jaredadams5194]

@konstantintrehagyrevopoulo972 yeah, it's a V8. Passenger side bank. I put all new injectors and plugs in as well. Also has a new intake manifold and IAC valve.

[@jaredadams5194]

@konstantintrehagyrevopoulo972 they use coil packs, the coils are all new as well. I replaced then when I replaced the plugs

[@rrmech11]

I liked the injector on time portion showing the computer adjusting. o2 sensor response is very critical too. Meaning a lazy o2 signal or o2 heater circuit. 👍👍

[@BrianMann216]

Absolutely, I want to make a follow up video showing what can happen in different scenarios. It is harder to do. Like a lazy o2 the pcm may not be flagging a dtc, but it knows that somethings off and may start to correct. This is going to be fun to try and catch and share.. thanks for watching and commenting.

[@B-ROCK843]

Thank you for taking the time to make the video. This is really helped me gain a much better understanding on the subject.

[@MarkSmith-js2pu]

Thank you so much. I’m not a pro, but I’ve made it a goal of mine to understand fuel trims. I’m a pilot, and your airplane trim analogy did the trick. I have a low level scan tool that I’m trying to understand for my car and at least now I can get the high level overview that previously escaped me. It’s a 11 yr old 3.6 GM with 160,000 miles that seems to run quite well, but as they say knowledge is power. I subbed.

[@BrianMann216]

I love Flying,( student, 172 and 152 mostly 12 years ago)..

[@ruimvp]

Thank you. Finally i understood LTFT. Fuel trims are important also for unmetered air issues.

[@videosenutube]

Finally, a video that open my mind on what I have considered a very hard subject to understand .

[@BrianMann216]

I am glad to be able to help.

[@atomicdmt8763]

excellent video. The CAR controls really helps. In my case, it seemed I had to keep clearing out codes/pending codes until the LTFT came into compliance - after a badly leaking exhaust. I seem to be on the good path now! Cheers.

[@isaacdarkey871]

You just gained a follower for this awesome fuel trim tutorial,thanks for teaching me and many others 😀 👍

[@BrianMann216]

Thanks for watching!

[@kicknsystm]

I've taught many subjects not as a profession but as a friend or mentor. From math to my son or my lady friend's child, general mechanical skills to friends & family, even Martial Arts & Self Defense. I've always had a gift for teaching from different perspectives that the student could relate with & understand. You just did that for me! Thank you so much!

[@smedleybutler1969]

Wow best explanation for a beginning mechanic!

[@BrianMann216]

Thanks for watching, please share with any one that may benefit

[@Carrie-Mercado]

Thank you so much! You have explained Fuel Trim, this is an Incredible Golden Nugget of Knowledge!

[@BrianMann216]

Thanks for watching!

[@SkillSavvyDIY]

Best video out there on fuel trims! If someone can't understand this, then they are just not capable of understanding anything

[@craigiefconcert6493]

Nice explanation! I easily understand that the computer expects a certain fuel pressure and has a map of the expected injector pulse width for the flow of air into the engine, and corrects based on what’s being actually measured.

[@صلاحالحراصي-غ1ض]

This is the greatest explanation of fuel trims on KZbin. Just if you add oxygen sensor signal during fuel restriction, it will be great. Thank you sir ❤

[@BrianMann216]

My van has air fuel ratio sensors, so it's a bit different than a traditional o2

[@FroggyFrosch]

Well it helped me a lot to understand I had some sues with a p0420 and a irregular engine running thanks to this I solved it had a bad upper o2 sensor

[@hinojosa552]

This is the best explanation about fuel trims I ever seen , and well explained, thank you Teacher

[@careyautorepairs]

Definitely the best video on this topic on KZbin. Going to add this to my playlist. Thank you.

[@BrianMann216]

Thanks for watching!

[@Jpilgrim30]

Generic OBD2 gets overlooked by a lot of guys especially once they get their hands on higher end scan tools and wind up getting themselves in trouble chasing substituted values. I use Generic OBD 2 a lot when chasing issues such as fuel trim.

[@gofast228]

After watching many videos, YOUR video totally put short and long term fuel trim in perspective for me, Thx

[@BrianMann216]

Glad it helped

[@laird340]

That Rc car explanation was brilliant. I've never really understood short/long trim until now. Awesome explanation. Thank you for that simple but effective analogy.

[@anthonyheak3479]

Great explanation about ST and LT fuel trims

[@ivanstrickland7741]

THIS VIDEO IS A MUST WATCH WATCH 10 TIMES. MAYBE 11. AWESOME DUDE.

[@BrianMann216]

Thanks for watching!

[@g5153]

I already know about the theory. But the practical part is fantastic. Many thanks.

[@tootsrr1]

Awesome video I got a Foxwell NT809BT Scanner it's all setup just need more deeper understanding how to find faults Great video about fuel trim thanks

[@joewaynemitchell6363]

This kind sir was really informative I'm here in Jamaica and I have a 2007 Suzuki Grand Vitara that's running rich in bank 2 @ -22 . I'll be looking into that injectors tomorrow thank much

[@SS-U23]

Dynamic and useful explanation Thank you

[@Axeman428]

Great job of explaining fuel trims. I now understand exactly what’s going on with my injection and no guessing. Thanks!

[@lp6696]

Thanks for the video it was great! For people who study signal analysis the short term would be termed "high frequency noise" and long term would be DC offset

[@BrianMann216]

NICE analogy!!

[@High_Tech_Mountain]

Great representation of fuel trims! Love the RC car and the live car example! As always great content!

[@BrianMann216]

Thanks for watching, I know we have lots more to cover, my goal was to share the simplest way that I could come up with on the basics. Any suggestions always welcome!.

[@sanjaysheth425]

Very good explanation, in addition this is basically PID controlled

The very best explanation with visuals to tie it together. Great job

[@BrianMann216]

Thanks for the compliment and for watching!

[@lohikarhu734]

It's important to understand that the short term adjustment is always added/subtracted to/from the long term, to get the correct 'instantaneous' fuel/air balance, as seen by the O2 sensor...

[@soilmanted]

Best video, best information, I've found so far regarding fuel trims. Nice and clear. I especially like how Mr HoAT set up a system to reduce fuel pressure to the injectors, showed us a gauge that was indicating the pressure and the changes in pressure, and showed us how the OBD trim values changed in response to the changes in fuel pressure - changed in order to keep the vehicle at "homeostasis" as they call it in biological feedback systems. I loved the info about the etymological origin of the word "trim" - starting with how the word is used, what it means, in the context of sailing vessels. Only thing I had some difficulty understanding was the fuel injector oscillograph pattern starting at 21:20. I think the problem here was that I was not able to see the labels for the vertical and horizontal axes. The labels were too small to see. I saw what looked like 2-digit numbers on the vertical axis that were too blurry to actually read, and in addition I saw just the numbers, I did not see any label saying what the numbers were a measurement of. Whatever was on the horizontal axis was even harder for me to see. Is it time, in milliseconds, on the horizontal scale? At what frequency was the oscilloscope re-drawing the screen? What was on the vertical scale, volts? Why was an increase in injector on-time associated with a flat, horizontal line at the _bottom_ of the vertical scale (a line which got longer as the fuel trim went more positive)?

[@beachboardfan9544]

Great way of explaining this, the steering alignment analogy is very intuitive 👍

[@sjsnopek]

I loved the practical demonstration! Thank you.

[@mnewln1800]

I run a shop and will share this with an up and coming mechanic. Thank you!

[@BrianMann216]

Your very welcome, please have the up and coming tech like and subscribe!

[@protocon59]

😃wow, I just came across your stellar teaching on this topic of fuel trims! Bravo! Short & Long adding together and understanding how fuel pressure can impact the duty cycle of the injectors as well as all the trim. This is helping me take over the troubleshooting of a lean condition on a Cadillac engine with codes 171 and 174 (lean on banks one and two). I'm looking at fuel pressure tomorrow and your excellent teaching has put me on a path that I think i can solve it. Thank you sir. -jeff

[@mustaphahammadi208]

Thank you very much for your well explanation. Now I have a better understanding of fuel trim than before.

[@bme7491]

Basic control theory. Many systems in the modern car are using a PID control loop to maintain some kind of stasis, e.g., fuel ratio, cruise speed....etc. Some of the most fun projects I ever worked on were based on this.

[@dangleybrush6103]

Never understood it one bit before this video. Thanks alot, that was very well explained and alot of useful effort went into it

[@rkeesee916]

Nice analogy with the r/c car. Thanks for posting👍

[@cliff499]

Man this is terrific I’m showing my junior techs this!!!

[@BrianMann216]

I hope it helps them out.. If there are interested in my basic electricity course have them sign up and take it , on the corr membership, its 10 bucks a month, just cancel before the renewal

[@cliff499]

@@BrianMann216 I don’t know what they learn in “tech school”. But in the real world they don’t get it. They never even heard of Load testing a circuit 😱. I tell them all to follow and listen and learn from you!!

[@bernhordwiebe3175]

That's a very good example. Nice in clear

[@BrianMann216]

Thank you for your comment.

[@KLNYC]

Finally, understand fuel trimming. thx

[@BrianMann216]

Glad I could help clear it up!

[@jackrein293]

One of the best explanations I've seen. Great work. Thank you.

[@JaneSanders-n6b]

Great video! I learned a lot! Thanks for taking the time to do this.

[@nateshoemaker2729]

What an awesome video! Super easy to understand. Thanks!

[@thechosenwon2207]

Very well put together. I finally get it , Ty

[@Justin_Webb]

Excellent video. The most concise I've seen to date. I enjoyed watching.

[@BrianMann216]

Thanks for the comment. I enjoy finding ways to share things differently.

[@davesales3129]

That was a very good demonstration. I can see that the computer is always correcting to optimize the fuel trim. I suppose that understanding what information the computer needs to control fuel trim will be in future lessons. Thank you!🖖🏻

[@BrianMann216]

Yes understanding the inputs is something to discuss for sure. It gets interesting quickly once introducing af sensors lambda / equivalency ratio.. personally in my day to day fuel trims can lead me to repairing the vehicle.

[@MouadAwad]

That was an amazing overview for fuel trims, keep this up 🔥🔥

[@brianritchie75]

I'm going to use my old RC car to teach this to my apprentice. Great demonstration here

[@reiannaidoo]

This is just the best video on the internet explaining fuel trims. Thank you.

[@BrianMann216]

Thanks for commenting! I think a part 2 is in order diving a bit deeper.

[@David-bp1tr]

BEING IN THE TRANSPORTATION REPAIR FIELD FOR 50 YEARS NOW AM STARTING TO UNDERSTAND FUEL TRIM PLUS THE REASON WHY THE READING ARE POS-NEG.AII THIS I KNEW I HAVE THE UNDERSTANDING,I FEEL IT THE PERSON WHO TEACHING IF YOU CANNOT GET THAT TECH TO SEE ARE UNDERSTAND WHAT YOU TRYING TO SAY. YOU ARE WASTING HIS TIME& YOUR, PLEASE KEEP-UP THE GREAT WORK, [ DADDYDAVE 707 ]

[@francisdsa6790]

Appreciate your demonstration and information about the fuel trim. Thankful to you 🙏💐

[@HasSan-jj4nl]

A very excellent explanation and we have benefited from the basics and we are waiting for more information.. I have subscribed to the channel and activate the bell to receive more. Thank you very much😇

[@abdelssami]

What an amazing explanation of ST LT 🎉🎉 thanks

[@joeseda8102]

I really enjoyed this very cool and simple explanation about fuel trims. Wish you had explained that to me 27 years ago! Have a wonderful New Year 2022 with family and friends. Same for all other commentators.

[@BrianMann216]

Thank you for the Comment. I plan to build upon that video lessons and go into showing cause and effect.. still not to much with the o2 or af sensors, because I rarely need to take it that far. Have a great 2022. Happy New year

[@raymondmcwilliams2823]

Brilliant well explaind 👍

[@carldymond110]

Thanks for the lesson.

[@brenyz5013]

Very well done vid !!!

[@BrianMann216]

Thanks for watching

[@javiertorres9666]

Thanks for the Video its So Easy Now i Got it 100% 👍🏼

[@KhalilAntoine-g2w]

Very informative, bro. It's greatly appreciated

[@rosselnator]

Great explanation!

[@BrianMann216]

Thanks!

[@munrys]

Great job explaining fuel trim. I can tell your a good instructor! You made easy to understand why and how fuel trim works. The real time lab was a great learning tool.

[@waverider5751]

I put four new Denso fuel injectors in my Civic with the R18a, and although it runs well, the fuel trims went from negative 5-8%, to positive 4-6%. Does this tell me my new injectors are undersized?

[@Bobo-t5u]

This video was excellent!

[@ralcng]

he is the best in this section

[@user-we5mi6zl2s]

Excellent l really like the live demonstration.

[@amiryaser91]

You really nailed it , thank you 🌷

[@BrianMann216]

Thanks for watching. this is as simple as I can explain it at this time.

[@raymondtorres7867]

Excellent teaching love it and tank you

[@Steve.191]

Your very good teacher thank you 👍

[@kriscarpenter6583]

thank you for simplifying fuel trim, i have a snowmobile turbo boondocker setup with 5psi of boost when purchased. Turbo blew, i brought sled to Mod shop that does sled mods but they could only get 14psi as new low . So now i have to purchase av gas too keep the sled cooler, like the power but its not my liking. id like to put back to stock if i can. Would i be able to just unplug the boondocker fuel mapping box from the efi carbs and plug in the original back in to get stock settings. i will also be putting original exhaust back on also and remove turbo.

[@kriscarpenter6583]

someone mentioned in forums you could leave the turbo installed and just unplug the boondocker fuel mapping box and just plug the originals back in, reason being i don't want to seize motor and would be happy with stock

[@BrianMann216]

I am not familiar with systems you have.

[@notone4029]

Thanks Much! Explained WELL in layman’s terms.

[@Lambros_Stefaneas]

Very very good video. simple and understandable. thanks.

[@rubendawn7478]

Thank you for sharing your knowledge and experience!!!

[@davidhilling6191]

Great presentation.

[@GrievenceCapitolist]

Nice . Improved my understanding of fuel trim by 1000 %

[@BrianMann216]

I would like to dona part 2 mote indepth sometime

[@GrievenceCapitolist]

@@BrianMann216 I'll watch it .

[@Justme001..]

Thank you very much for this Excellent explanation!!!

[@kylevarble2325]

That was awesome and very informative

[@BrianMann216]

Thanks for watching, please consider subscribing if you are not already!

[@dinonaccarato2989]

I’m new to the mechanics world of engines. I now do have a much better understanding of how Trims work. My question is, how can we use the information that we see on an OBD scanner on trims to help us fine-tune performance? Or diagnose issues. Cheers from Canada

[@georgebonney90]

Great video, thank you sir 👍

[@bFORCe2003]

Have a 2000 Honda Civic P0132 code. STFT: went all the way to -50% LTFT: Hovered around -4% O2 Sensor B1S1 - fluctuating between 0.1V to 0.7V O2 Sensor B1S2 - Stayed at 1.2V

[@dumbeezy5480]

Test your O2s

[@jordysandino6577]

Hello sir . Great video . I’m starting watching your videos . Question do we need to add the 2 banks to see results or just both trim at 1 bank ? I’m sorry I didn’t get that part. Thank you sir .

[@BB010864]

Thanks for the simple explanation ! Great Video !

[@BrianMann216]

Thanks for watching, I should make a part 2 going a bit deeper into fuel control and correction, what do you think?

[@BB010864]

@@BrianMann216 I would like to really see how to read 02 sensors and understand how they function and diagnose :)

[@Kntryhart]

Good stuff! Thanks for posting!!

[@wentzelnel7723]

Thank you. Was a brilliant way of explaining it.

[@herculesmoutas5540]

Very helpful video! My car yesterday on idle reached -45 Short term and +16 Long term. With the rpms at 2000 both was 18-19. What would that be?

[@kanaslens4038]

Great Info! On point. Nice and easy to follow

[@JCGible]

Great explination. I could actually understand it somewhat.. so if my long-term creeps up to +20 and stays there, I have a problem. A vacuum leak that I can't find. 😡

[@JCGible]

I replaced the fuel pump and filter. Fuel pressure gage holds between 50 and 60 psi 👍 I actually hate working on cars. Theres just so many better things to be doing. Anything, really.