Advanced Fuel Trim Diagnostics

[@davidsinclair5004]

I am just always so blown away by Bernie’s methodical and yet lighting fast diagnostics, watching Bernie makes me feel inadequate. Thanks Bernie for yet another great educational video..

[@SamuriaPizzaCat]

This man cant stop producing straight FIRE !

[@theblacksheep8473]

One of the best in the game as a young tech definitely following closely

[@scaracci24]

So passionate about this stuff, the man makes himself cough. Like a peacher about fuel trims. Love it!

[@BigDogDiagnostics]

Every video I’ve seen from you is methodical and fundamentally gold! Thanks for spreading your knowledge, people like you make the whole industry better!

[@CartersDiagnostics]

Around the 51 min. mark he speaks of the MAF voltage being low on this KIA. The "rule of thumb" measurement of 2.7v to 2.8v that he uses I 100% agree with, Just to point out this is a good number for a 6 CYLINDER engine... A 4 CYLINDER engine "rule of thumb" in my experience is 2.2V to 2.4V on the MAF testing. Great video as always.

[@sunjoomoontube]

000

[@PineHollowAutoDiagnostics]

Love the passion, Bernie! Fantastic seminar! Question on VE: the theoretical mass air flow (g/sec) = [inlet air density (g/L) x Displacement (L) x RPM (1/min)/2/60 (sec/min)]. For a 3.4L engine at 800rpm idle I get 9.7g/sec. Why is this not closer to the rule of thumb 3.4g/sec? Inlet air density I assume is 1.28g/L x 1/3 since the intake manifold pressure at idle is roughly 1/3 of atmosphere...

[@kerryb2689]

I'm studying this in depth to help diagnose fuel trim/lean problems now. Dry Air density at sea level 77 deg F is 1.184 g/L. (A penny is 2.5g for reference) Density is proportional to absolute pressure (MAP). It also depends on absolute Temperature, and to a lesser extent humidity. (search for Air Density Calculator) Pressure at sea level is 101.325 kpa, so you can think of a kpa MAP reading as a percentage of pressure and therefore density. So at an idle MAP of 26 kpa, air density is 26% of 1.184 = 0.308 g/L You must also take into account Volumetric Efficency (VE) of an engine which also varies greatly with RPM and MAP from about 60% to 90% +/-. (search for VE table) The RPM-VE relationship has to do with resonant frequencies of the intake and exhaust pulses in the manifolds and tuning these (think of playing a trombone). Max VE is always at peak torque RPM where the engine breathes the best. I have been using this info to try to calculate MAF, from speed density and always come up 10-20% more than I am seeing from my MAF sensor...(I don't have a known good/bad MAF sensor). I suppose I could always just unplug the MAF and see what fuel trim tells me, but what fun would that be :-), and besides that won't tell me if i have a vacuum leak or bad MAF. I was surprised at the MAP data when increasing RPM in Park when I graphed MAP, MAF, RPM, and Calculated LOAD, but then after thinking about it, it made sense. 27-->21-->24 Fuel consumption is MAF/14.7 while properly working O2 sensors are switching, and 12.7 under fuel enrichment at max power. Fuel density is 0.75 g/cc (75% of water). There are 231 cubic inches in a gallon, and 2.54^3 cc in a cubic inch.

[@sinegra30]

Nice Question Ivan! I guess is because we have to consider ground elevation and air temperature into the calculations for proper air density. I recently found this channel, Bernie is awesome! Can't believe is still for free!

[@PineHollowAutoDiagnostics]

@@sinegra30 Yeah Bernie is in a league of his own...the mad scientist of auto diagnostics :)

[@paulpaquette1961]

Ivan, the reason it is not closer to the rule of thumb, is because of the throttle plate, it is closed at idle. An engine at idle has a VE of 20% ish...The down and dirty formula I like is this (RPM/60) X (DISPl./2). So with your 3.4L engine at 800 rpm you get 22.7 g/s, BUT the engine is only 20% efficient therefore 22.7 - (22.7 X 0.8) = 4.5 g/s. But that 20% is also a rule of thumb. Theoretical Airflow for our use in diagnostics is best used at high engine rpms where we expect VE's of 80+%. I know it's been a year, hope this helps.

[@johnnysprocketz]

Bernie will respond when you start using ATS testing systems on your channel.

[@bme7491]

Great explanation. I just replaced a MAF on my Toyota, getting code for lean on both banks. I only figured it was the MAF after running a 3 drive cycle procedure based on a Service Bulletin and seeing that the final MAF reading (with ignition on but engine off) was over the spec limit. New MAF did the trick.

[@malibuStroker]

Great video but would love to hear the question and answers as well. Thank you for what you do!

[@michaelr6205]

I LOVE THESE PRESENTATIONS. More please!!!

[@orville58]

Thank you Bernie you have helped me more than you will ever know .

[@swordofthelord7104]

Great video, great knowledge and great passion!

[@rdaleyj1]

Wow so fuel trim is the computer adding a+ or- % air rather than fuel??? I had this wrong for years.

[@theautomotivedoctormr.wils9217]

Thanks for sharing this class Bernie , very informative .

[@IAMNOSLEEP]

I watched this during the live webinar. Watched again here. Thanks for the great info. Cheers...

[@Joe.O_623]

This is SOLID GOLD!

[@arthurfricchione8119]

Bernie great explanation. Can’t wait to watch the rest of your videos even the ones you have to subscribe to. Thanks so much for sharing your knowledge. Artie

[@jeffgoetz7919]

Incredible lecture. Thank you

[@linxstudent1682]

full comand of the facts. brilliant job.

[@mike-yp1uk]

What a great understanding. I enjoyed this one a lot.

[@williamj1969]

Thank you for making this video. Great education!! Thanks again.

[@thisisausername1265]

Great case studies; thank you for sharing.

[@magrisers]

Bad mechanic = parts changer, good mechanic = reverse engineer.... you have to watch entire video to understand

[@romanjaspe4172]

Thanks so much. Interesting!. God bless you

[@royarena6232]

New subscriber. Thank you.for taking the time to make these videos and share your knowledge.

[@RideBikes_Walkplaces]

If the injectors have a higher rail pressure will they inject more fuel per ms if the injector hole size stays the same? Or is it just the size of the hole/time open that dictates how much fuel is injected?

[@proudofthe3211]

Automotive Science at its best! 👍🥇🎯🔎💡🔬

[@carstengotfredsen160]

Super video :) from Denmark

[@frankyv5999]

thank you sooo much for your videos. they are priceless

[@RAVETOR]

I love this! Thank you for making this video!

[@marvingutierrez1217]

Thank you so much .you are the man

[@I999-g2s]

Wow - amazing example of how to needlessly complicate the explanation of principles, that aren’t nearly as complex as all of this has been made to sound.

[@hightttech]

EXCELLENT PRESENTATION.

[@sweetjordan4868]

Awesome

[@alexlee4573]

The video is great, but I don't understand (21:00) the calculation. Let's imagine we have four cylinders engine - each revolution of the engine has TWO intake strokes. So if the engine produces 13,3 RPS, there would be 13,3 times 2 equal 26,6 Intake Strokes Per Second. In video we have 8 cylinders engine and only 3,33 ISPS. May be I haven't understood - English isn't my home language.

[@carlodonnell146]

What occurs to me is that if the ALPHA N works, why are MAF sensors and MAP necessary in the first place. The car makers keeps making things more and more complicated every year.

[@Savagetech96]

I love it, thanks!

[@gearstil]

How can I find the teorethical VE? The red line that he uses to compare with the MAF calculation.

[@ShitWrangler]

that's a proprietary algorithm encrypted inside the ats scan tool

[@ShitWrangler]

Actually I just found out Bernie got a lot of his materials from the Bosch Automotive Handbook and just transferred the values into his tool. Smart. Been on a youtube fuel trim rampage and one of the other channels revealed his secrets

[@molenz1960]

As a speaker, I feel he had a 3 hour lecture and was told condense it to one hour, so he just talked as fast as he could.

[@nestorsuva6700]

Hello,after Iam watching your video now I have a question in my mindthat I would like to ask you..in a 2.4 petrol engine at idle how could I get the right mass air flow (grams/sec) of an engine... Thanks .iam here in Darwin

[@gustavomartinez324]

It’s usually 2.4 Liter engine should be 2.40 grams per second that a rule of thumb to overcome the parasadic loss of the motor any questions feel free to ask

[@gustavomartinez324]

U multiply it by 40 for a wide open throttle give u a estimate of how the engine is breathing VE volumetric efficiency

[@nestorsuva6700]

Thanks for the good information

[@gustavomartinez324]

@@nestorsuva6700 no problem 🫡

[@jhauna1]

What would be considered a low VE number? Thanks

[@timm5970]

1

[@orlandocortes8022]

Subtítulos en español sería grandioso 🔧🔩🔧🔩

[@juergenscholl2843]

Thank you!

[@victorgonza4528]

Master class

[@orlandocortes8022]

Estoy interesado,necesitaría subtítulos en español

[@timm5970]

youtube tiene subtitulos en espanol para ti guey

[@screamingflat6]

Hot rod bullshit -- Burnie Thompson

[@shakeelsss]

Thanks a ron

[@robertmcdonald9715]

8>

[@fascistpedant758]

Your math is a little wonky. 1 US gallon (not 1pound) = 3785 cc. 46 lbs./hr. = 7.74 cc/sec. = 464.3 cc/min..

[@Finite-Tuning]

All your injector talk is irrelevant until you put it into an "engine", not a motor! Motor this, motor that, ain't none of ya replaced a windshield wiper engine! have you? How about a power window engine? Did ya replace one yet? No? An engine deals with combustion, regardless of internal or external. A motor is electrical, always! Both can provide a motive force, but only one runs on fuel. I feel we are too far past the time for kindness, it's time you and your kind start to get it right! It's not a motor, it's an engine. It's not an engine, it's a motor..... Learn the difference and teach it correctly!

[@MrBeefsnorkel]

do you just regurgitate nonsense you read on facebook and the internet? go look up the actual definition for a motor on google (it'll take you 3 seconds, promise) and get back to us. start thinking for yourself instead of going with whatever fresh meme is circulating. hint: google's definition includes pictures of engines

[@Finite-Tuning]

@@MrBeefsnorkel: Clearly you need to be properly schooled since you were obviously taught by the general ignorant populous. They have it wrong and so do you! Keep on regurgitating a lie if you like, but I'll keep on telling the truth the way it actually is!

[@lorenfrank8088]

It must kill you when registering your car at the D "M" V. I'll bet you would never buy a "motor"cycle or have any kind of "motor"sports equipment.

[@Joe.O_623]

Bro, maybe you are not aware that Bernie Thompson is probably one of the most respected and knowledgeable people in the United States at what he does. I just checked out your videos on reheating pizza on the barbecue grill and snowblower review and they kinda sucked.

[@Finite-Tuning]

@@Joe.O_623 And yet I'm still not wrong!