Short Term and Long Term Fuel Trims Explained [Easily]

[@TalyerMotorsph]

Great vid. I would like to see a 5 volts reference video for beginners the basic ,how to read wiring diagrams and voltage drop. Thank you

[@stryker4374]

We need more of these!!!

[@MasterAutomotiveTraining]

Thank you for watching, you bet working on more for you guys!

[@TalyerMotorsph]

Yes!!

[@Grâce-n1d4x]

Finally, I was able to understand after watching a ton of KZbin videos. And yes, I’m an 80’s kid.

[@ThunderbirdRocket]

Extraordinary detail ! Super helpful !! I learned lots !!! Thank you.

[@MasterAutomotiveTraining]

You're very welcome, and glad it was helpful!

[@bartscave]

Still have my 1976 smog and lamp license… this video brings back memories!

[@MasterAutomotiveTraining]

No way thats awesome! Glad I was able to help ya down memory lane!

[@juansalazar7944]

Very valuable information ,Thank you for sharing.

[@catbert007]

Thanks bro ! I have a DM model with exactly the same problem ! Thanks to your video, I can easily pinpoint and solve the problem 👍👍👍

[@Hscope-User]

Gracias maestro👍🏼🤝

[@MasterAutomotiveTraining]

Gracias a usted maestro!

[@isitreal1459]

Wow! Awesome lessons I am hooked to your classes and appreciate your teachings I just subscribed and will be looking forward to all your videos. Thank you buddy

[@MasterAutomotiveTraining]

Welcome aboard! Thank you for watching and look forward to helping you!

[@martinezautodiag1670]

Great information, thanks Oscar

[@MasterAutomotiveTraining]

Thank you Maestro! Saludos!

[@crasher88]

lots of good information thank you. Request: can you do a video dedicated to wide band O2 sensor testing and diagnostics and using them to determine a good or bad cat? In my experience when a manufacture puts a wide band O2 sensor in the up stream sensor the fuel trims typically don't swing like they do a standard zirconia O2 sensor. With no swinging fuel trims the reading from the O2 sensor doesn't swing but stays steady and I don't understand how to use that information for diagnostic purpose.

[@MasterAutomotiveTraining]

You bet buddy! Ill get something put together for ya!

[@MarkOshkeshequoam-m7i]

This was very useful and informative. it gave me a better understanding of stft and ltft. Thank you and yeah, let's see more videos.

[@scottykilmer3920]

This guy is Gold ! 👌👌

[@alexreis5530]

Thanks Oscar ..one more peace on my brain connected appreciate

[@MasterAutomotiveTraining]

You are very welcome and thank you for watching!

[@GordonHaaland]

Great job.

[@Litor2121]

Great video, man. I'm trying to learn to be as good as you when it comes to diagnostic. Didn't go to school to learn these things just learned all hands on. I have a 2015 Buick Regal 2.0T p0171 code it's running lean at idle and coming to a stop long term goes up. I've smoked it and no leaks found along with cleaning the carbon up valves. I have data available if you don't mind helping.

[@rdaleyj1]

Great lesson Oscar thnx.

[@nickayivor8432]

Outstanding tutorial,Oscar Gomez My Mentor 👍 WHIP SMART,Oscar Gomez Master Automotive Training Enjoy your weekend with all your family around you,Oscar Gomez From Nick Ayivor from London England UK 🇬🇧 ⏰️ 17:08 Good Afternoon

[@raymondstucker1609]

Ty for ur time

[@blessevans6808]

Thanks very good video

[@shaffere33]

Great stuff!! Thank you for the content

[@ashercohen4739]

thanks👍

[@TalyerMotorsph]

Oscar can you do a video for G1 test prep/boot camp for new tech entering the field. Thank you

[@patrioticimmigrant8817]

Where can i get these slides? This is perfectly explained. I always get confused between makes and knowing each spec.

[@jameshall5314]

Was that scan tool you used in this the topdon topscan?

[@rommeltolentino5954]

Can explained about the air fuel and ratio sensor is always not ready in emissions on2005 toyota corolla Ce.

[@MasterAutomotiveTraining]

That's normally because the vehicle hasn't been driven in the right drive pattern to test and complete the readiness flag.

[@rommeltolentino5954]

@@MasterAutomotiveTraining Thank you very much.

[@Nes_2k]

What if a stft is fluctuating from -25 to +25, only code is p0661 Mazda. Used propane, smoke test and couldn't find nothing to save my life. Great video!

[@henridekker9132]

Finally understanding Fuel Trims at 72 🤓

[@GERONIMO326]

Hey man, what would cause my long term fuel trims to be super negative at idle, and go even MORE negative as throttle is applied? I have a 2019 Camaro SS V8 and its like -17 on one bank and -22 on the other. All stock car other than Rotofab cold air intake. Tried new oem maf, oem o2s both primary, oem plugs and wires, new oem pcv, there is no cel on. Car stumbles at light throttle lower rpm usually around 2k rpm is when it starts to buck a little. Wot clears it up, or it runs better when you keep it above 2500 rpm. Starts fine, seems to idle fine even though its a little shaky at idle.

[@MasterAutomotiveTraining]

Does the vehicle have a MAP Sensor or MAF or both?

[@GERONIMO326]

@@MasterAutomotiveTraining it has both sir, thank you for taking the time to reply to me, I'm so desperate! Lol

[@GERONIMO326]

@MasterAutomotiveTraining speaking of MAP sensor, I did unplug it yesterday and plugged it back in (with vehicle completely turned off). Just to see if it would make a difference. Drove it a few miles, came home and plugged up my OBD2 reader to re check the fuel trims, and there was a pending p0106 and p0107 code (map sensor circuit low) (keep in mind there was no cel, I just stumbled upon it checking fuel trims) It then went away, shortly there after. When I unplugged and replugged it back in, I did it with vehicle completely off. Someone said a bad map sensor could cause it to run rich (negative fuel trim) seems like the car has the most trouble when under heavy vacuum if that makes sense.

[@MasterAutomotiveTraining]

@@GERONIMO326 You are very welcome. A MAF usually causes a lean condition. Id be suspecting a MAP sensor that is misreading. What is the MAP sensor reading at idle?

[@GERONIMO326]

@MasterAutomotiveTraining 9.8 inHg (or 33.1 KPA) and as I revved the car to 2k rpm stationary in neutral it went down to 6.3 inHg (or 21.3 KPA)

[@chrisisho2557]

LTFT 26% STFT 25%, Short-term increasing with high RPM and long-term decrease with high RPM, any suggestions as suggestions as replaced Fuel pump and filter but still the same, you think bad fuel injectors ?

[@MasterAutomotiveTraining]

Have you done a WOT snap and seen if loop status goes OL and see if O2 goes full rich?

[@chrisisho2557]

@MasterAutomotiveTraining may I know what WOT snap mean ?

[@johnjauregui3528]

How does ethanol affect ECM/PCM fuel trim calculations? Does it require the same 14.7 ratio calculations or some other ratio? If so does the ECM/PCM sense whether the fuel is ethanol or gasoline and use a different ratio for ethanol? If the ECM/PCM assume gasoline is used and does not adjust for the use of ethanol what is the impact on air/fuel calculations and fuel trim outputs? How does this affect scanner outputs, rich, lean, etc.? Is there a YT video that addresses these questions? Bottomline: How does the ECM/PCM adjust for these two different fuel types with different optimum air/fuel ratios, or does it not, and what are the impacts on scanner readings and diagnosis? Again, is there a YT video that addresses these questions?

[@GordonHaaland]

Po401 ?

[@gasisthepastendoil]

Okay if the PCM compensates For a positive or negative fuel trim then why even bother with it as a repair in the 1st place can I just tell the customer not to worry about it????🎉🎉🎉🎉