Fuel Trims-Testing & Diagnosing Rich and Lean Conditions (P0171, P0172, P0174, P0175)
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We are finally diagnosing our GTO. It is time to apply all that we have learned over these last few months. We show many different ways to test for different lean and rich concerns on your vehicle. Ranging from quick and easy to more in depth. At the end of this training you should have a good understanding on how to pursue a rich or lean code.
As always, if you like what you see please subscribe, thumbs up and share! Thank you!
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I’m a Nissan Master technician. 25 years experience. Your video’s are the best I’ve seen on TH-cam. Keep it up!!
Thanks MrJoeyB!!! Glad you're lovin on classes! :)
Mike Becker, Technical Services Instructor
Hey Mr Joey sorry to ask but i have a 03 pathfinder that i completely rebuilt the vq35de in it last year down to regrind and cylinder hone. compression is 185-195 between all cylinder after rebuild. Was having a intermittent hard start last week that was fixed with a fuel pressure reg and dampner along with a new fuel pump. my LTFT are right at -5.5 on both banks. shouldnt they be closer to 0 - +/-1?
Guys, Thank You. It is awesome being able to interpret the data on my scan tool. I thought I knew what it was saying but it turns out I really didn't, until know. I can not tell you how informative the class was. I think I just raised my game.
Hey Bryan, thank you so much! Glad we could help raise up your game.
Mike Becker, Senior Instructor
Marie sent me over with the rest of the crowd.
Subbed.
Nice! Welcome :)
Mike Becker, Senior Technical Instructor
came over from SMA, very informative video, thanks.
Hey thanks Jack!
Mike Becker, Senior Technical Instructor
Hi miss Marie sent me
Sweeeeeeeeet :)
Mike Becker, Senior Technical Instructor
@@kenrhodes8132 same for me
Add me to the list. Miss Marie said hello
Me 4!
She's doing a great job learning!
Have you watched her video on SMA?
New sub here!
Me too. Though I already watched and loved your Audi brake booster video
Ms Marie from South Main Auto recommended. Very good...even for those of us who are just hobbyists rather than professionals. Beautifully explained. Very helpful.
Hey Mark, thanks and welcome!
Mike Becker, Senior Technical Instructor
Great video. I had this same diagnosis based off the pids. Fuel trims with readings alone with both banks were a clear indication. Reading active O2 would have also pointed that direction. Could have also looked for a lack of fuel but considering least intrusive diagnostics first the Vac leak is the most likely culprit with the easiest tests to verify.
Thanks for watching!
Hahaha love the "don't think that's measured in ugga duggas" comment! Great videos guys, I'm a DIY'er but I've learned more about closed loop fuel systems and related sensors in your last couple of videos than I ever thought was necessary - but now it's clear that it is.
Hey Landis, thanks for watching! Information is power :)
Mike Becker, Senior Technical Instructor
Miss Marie and Eric O sent me here and you got a new sub. Great channel
Joe Bellanger me to. Good video
Hey Joe, welcome, thanks!
Mike Becker, Senior Technical Instructor
Good video and helpful to see actual diagnostic readings from the car - recommend.
Hello Mike,
Remove air intake manifold, discovered piston #1-, its air port, had carbon build-up in gobbles.
Replaced the gasket torque it to 13.666 inch lbs, checked fuel trims: long term was higher 10 mv idling, on acceleration it when up to 39.45 mv.
short term, was -8 to -15 idling, on acceleration it dropped to zero and to .5 mv
I re-torqued the manifold while hot, the long term is now stable at 2.3 mv
short term between -5 to -14 while idling.
accelerating while driving the shorterm is stable between 2.3 to .5 mv
short term moved to positive 5.
deceleration drops to 00 to -.1 to -.5 to -.10 it stays on the ten.
removed spark plugs very clean no fouling, replaced with new sparks.
injectors replaced too.
checked with stethoscope all injectors sound good crispy and tight. the spark plug sound chirpy good frequency. however the piston chamber # 1 sound like weak oil rings, other piston sound clean and clear.
Could the short term trims stable at -10; long term stable at 2.3 is this a sign of low compression?
Oil was changed added 3.75 quarts after driving for one hour the next day checked oil it lost .25 oz it could be burning oil yet no signs of it coming out of exhaust pipe.
checked vaccum with pump its at 22lbs perfect.
check engine light is still on, I did not remove battery cable while working on it. Should I remove battery cable wait 3 minutes and re-connect it to see if the check engine light disappears?
The on board computer tester still brings up code P0171.
There was a pending code P0125 throttle position senor, thats because i did not tighten the bracket to ground enough it gone now after tightening its bracket to engine block.
I have a 02 f150 4.2 with a bank 1&2 sensor one both sides.
I have done an intake job reseal.
Also did a timing cover replacement and replace synchronizer .
Also changed MAF because of damage to the MAF
Stuck open EGR on MAF will skew MAF reading makeing that system runing lean. We call it inside air leak, the sneaky pirate.
Heres firsth video that i did find for EGR with MAF and its from Paul Danner so yeah. th-cam.com/video/zIZCbn7aaME/w-d-xo.html
I personaly have never sean car that runs rich as EGR is open but then again 99% cars that i see in front of me have MAF engine in them.
Thanks for watching! I like that, the sneaky pirate!
Mike Becker, Senior Technical Instructor
I realise the video is old and that competition is finished long time ago but i'd like to verify my answer. Answer:
A stuck open EGR will throw a lean code because a stuck open EGR is basically a huge vacuum leak, letting massive amounts of unmetered air going into the engine which will obviously be detected by 02 causing the ECU to call for more fuel. Thank you for your time
Hey Rok, thanks for trying at the question anyway. I respond with a question...is an EGR being stuck open a vacuum leak? How much oxygen is in EGR gas? ;)
Mike Becker, Senior Technical Instructor
Hello, just to (try)answer your questions. EGR sits between exhaust and intake manifold, right? Therefore, a stuck open EGR will create a vacuum leak by allowing the air from intake to escape, at least partially. As for the second question, there would be none or very little, and i know that you've mentioned that in the video.
Thank you
Ms Marie recommended this vid.
Awesome Spunkmire!
Mike Becker, Senior Technical Instructor
That’s why I’m here
The EGR stuck open would cause a lean code because the air entering the intake manifold would be unmetered... not being metered by the mass airflow sensor would throw off the fuel trim to lean... letting in more air than fuel...
That was a GREAT demonstration with the E85 gas, especially with the blue coloring additive, but it didn't seem obvious why you were doing all those ethanol tests in the first place. The title of your video is "Fuel Trims-Testing & Diagnosing Rich and Lean Conditions", but you don't mention how ethanol impacts fuel trim. In a future video you may want to discuss that, along with the effects on fuel trim due to ambient temperature extremes, summer vs winter fuel blends, humidity, barometric pressure, variances in octane, etc. Keep in mind too that Trump is threatening to legalize E15 everywhere to gain brownie points in the cornbelt. If that happens, it's going to cause some trouble with older cars, especially older cars in disrepair, who's fuel trims are already close to the CEL limit.
Hey Jay, thanks for watching! If I remember right, the point of that part was to test for water/ethanol in the fuel when diagnosing rich/lean conditions. The goal wasn't to explain what happens when there's ethanol present, just that it's a test to perform when checking for it. I believe it was one or 2 classes prior to this one I went into explaining what happens with ethanol in fuel.
Mike Becker, Senior Technical Instructor
Ms. Marie from SMA sent me because apparently you're awesome.
Hahah I don't know about that. I'll let you formulate your own opinion!
Mike Becker, Senior Technical Instructor
Hey Mike. Miss Marie sent me. Feels like deja vu...lol.
Hey Mike, welcome back :) haha!
Mike Becker, Senior Technical Instructor
Tech B is correct due to the valve stuck open in this instance its letting more fumes pass than being calculated and it is acting like a vacuum leak and is a continuous flow of gasses.
Rookie mistake in which I did learn from keep them coming super great video.
Hahah glad you got it now! Thanks for watching.
Mike Becker, Senior Instructor
My thought- it will indicate Rich. Thinking- exhaust gas has very little oxygen, so the air into the engine will have Less than normal in And out when exhaust is added to the intake.
I'm a hobbyist, my own mech and Always learning. In lew of a smoke machine & tester I add trace refrigerant and use my leak checker! Bwaa haa haa!
I think the same concerning the EGR question.
Oh and good job keeping Ms Marie attention. Good thing you wasn't walking through it like a brake job.
Haha thanks man!
Mike Becker, Senior Technical Instructor
Thank you for your time and knowledge
Hey Naz 777, thanks for watching!
Mike Becker, Senior Technical Instructor
A bar setting educational class as usual, Thanks a lot.
Thank you!
Mike Becker, Senior Technical Services Instructor
Miss Marie from SMA sent me.
Awesome Jeff, welcome!
Mike Becker, Senior Technical Instructor
Thank You, this as been an EXCELLENT video.
Thank you for watching Rudolph!
Mike Becker, Senior Technical Instructor
ps eric o sent me what no good stuff? dontdaton!!!! hard for me4 im old you young kids are teaching old dog new tricks,keepn up the good work. thanks.
I love these workshop sessions. I've still not managed to catch a 'live' tutorial, but I catch up pretty quickly. Keep up the great work, guys!
Best wishes from London.
Hey Labrador McGraw, thanks for watching! It's been quite some time since i've gone live for a class. Hopefully soon i'll have another!
Mike Becker, Senior Instructor
The best videos out there. Thanks for teaching us all....
Thanks Mike! You've seen just about every video at this point, huh?!
Mike Becker, Senior Technical Instructor
@@GoTechTraining Trying to see all of them.. Cant get enough of the knowledge your giving out..
Brake clean is horrible for any intake usage. It strips the oil off the wall and damages the rings. I know from experience. It welded the ring and I had to throw away the pistons. It leaves little pellets of carbon. It's good to clean with. It's an oil cleaner. The put some lube in starter fluid that prevents welding.
A stuck EGR valve will create a referred code lean p0171. It is a false reference code to uneven pressure building up. The why, would be that o2 sensor will it as unmetered air reducing fuel; must cars are set to calibrate towards lean. gases backing up reduce incoming air. I tried this is lots of fun.
Hello! Good Morning! Ms Marie sent me here!
it is leaner as tech b said bcz it lowers the temp of engine which reduces complete burning[when engine is not hot enough] which leaves more oxygen for oxygen sensor to detect gives the lean mixture signal to pcm
Great thought, I like it. The correct answer really was either. Because under the correct conditions either situation is possible.
Mike Becker, Technical Services Instructor
Lean code because it’ll allow more air into the intake after the Mass AirFlow.
Second fuel test you must add 18 ml water to compensate evaporation of fuel from previously 100 ml fuel at measure cup which is now 90 ml.
The video Picture is not matching with the sound?
Good stuff on the fuel gage very well explained.
Thanks man!
Mike Becker, Senior Instructor
Great video. Do you know what ECU does in the presence of one P017... code? It will run a programmed map or will continue to use o2 sensors and others? What i understood it is that when P017... occurs the ECU knows that a problem exist but can not identify the cause. I hope i am right. Thank you.
hey mike. i love your vids. seems like NGK does not give you the same amount of time to go into detail
Hey Darren, it's pretty free to take as much time as needed. I try to keep them down to around an hour and a half. Once you go much longer you really start losing people. It really all depends on the lesson though.
Mike Becker, Senior Technical Instructor
great vid mike one of the best on the net thanks for shareing
Hey Mason, thanks!!!
Mike Becker, Senior Technical Instructor
if the egr is stuck open more inert gas will enter the cylinder which is non combustible causing there to be less oxygen in the cylinder causing a rich condition tech A is right
Miss Marie from South Main Auto sent me here
Awesome, welcome Ryan!
Mike Becker, Senior Technical Instructor
I would change those knock sensors, put some grease around them, keep water out ;)
Hey Smokey88, Super common issue on that engine, right?!
Mike Becker, Senior Instructor
im am by far not a drinker, im a smoker, but i do know that alcohols the only thing that has "legs" and that glass u were talkin about thats supposed to b premium fuel definitely had some self sustaining legs, they werent huge but definitely there
Subscribed. Miss Marie from SMA sent me.
Thanks and welcome!
Mike Becker, Senior Technical Instructor
I am staring to be familiar with fuel trims with your clear presetation
Awesome Lino! Glad it's helping.
Mike Becker, Senior Instructor
Dear sir very good demonstration thank a lot.
Thanks Zwe Marn!
Mike Becker, Senior Instructor
Eric, on the question from Fox Brenton asking you about acetylene. We need to be careful here, Remember acetylene EXPLODES at the presence of OIL. I had the experience of gas and carb cleaner exploding on me. Gas on my face and propane a few feet away when checking for leaks, needless to say gas is nastier (sudden long flame) than propane (sudden flash) I do not want to be there when acetylene explodes. Definitely NOT RECOMMENDED.
Great comment! Any sort of flammable gas should be used in extreme caution. Propane is the ideal choice for these situations.
Mike Becker, Senior Technical Instructor
It is the oxygen side of the oxy acetylene torch set up that reacts to the oils in an explosive way (petroleum based lubes). This is the same chemical reaction when those commercial jet blew up and crashed. It was hauling oxygen generators the had a compressor leak ( refrigerant oil was exposed to the pure oxygen casing an explosion. Granted-the acytlene is very farmable but lacks the explosive ability on its own but if you mix in the oxygen till you have a neutral flame and snuff it out the explosive /unstableness potential of the acetylene increases incredibly and will explode with the slightest exposure to excessive heat or a small spark . But if you were to expose that pure oxygen to oil that may be the first and last time that you will ever be able to try that experience again🪦
Ya that's what code reader saved
Miss Marie from SMA sent me over.
Hey Bill, welcome!
Mike Becker, Senior Technical Instructor
Ms Marie sent me Good Job
Hey Kerry, thanks!
Mike Becker, Senior Technical Instructor
Miss Maria sent me too! New sub
Sweet, welcome!
Mike Becker, Senior Technical Instructor
Marie sent me love your videos
Thanks Orville58!
Mike Becker, Senior Technical Instructor
There is never any detailed fuel trim videos on rich trim. I've replaced IAT, 02's, CT, MAF, MAP, N80 purge valve, i've tested for vacuum leaks, checked the FPR Cannot get rid of the rich fuel trim.
Rich conditions are less common than lean but can be diagnosed the same way. Force the engine lean, do the trims and 02's react accordingly? How's fuel pressure after the key is shut off? Maybe a leaky injector?
Mike Becker, Senior Technical Instructor
Thanks a lot for your videos and sharing your knowledge. I have a fault that both banks mixture are too rich. I checked the long term fuel trim (LTFT) using a cheap code reader, I found that on high way the LTFT is between 0 and -5%. When it's on idle or when I remove my feet on the accelerator pedal, it becomes really rich -20 to -25%. I bought a used MAF from the scrap and installed it but the problem persists. From your experience what can be the problem? Both banks have the problem, so I would rule out the injector leaking or spark plugs. I have a C250 4 matic V6 2012 gasoline. Thanks a lot
Hey 80goal, i'd be curious as to what the fuel pressure sensor reads. Maybe that reading is skewed and the fuel pressure is too high? Nothing is really common to that engine. Wish I had more to go off of for you.
Mike Becker, Senior Technical Instructor
It would be great if the recorded volume was a bit higher. I can be noisy when we are listing to the video classes. I have the volume at 100 % but still have a hard time catching everything that is said. Thank you.
Hey Richard, we have corrected this on more recent videos. Thanks for watching and commenting!
Mike Becker, Technical Services Instructor
If your old video has a channel for sound and another one for video you can Reedit the sound channel only and increase the volume. What software do you have? Just curious. Great video content.
What would make it stick at -10.9 new 02 only thing I can see is that the value cover seal is cracked would thay make it run rich
Another great informative video.
Thanks for another great comment Ross :)
Mike Becker, Senior Technical Instructor
Sent by Miss Marie!
Sweet!
Mike Becker, Senior Technical Instructor
whoops whay late . for swag . keep teaching your #1
Make sure to check out our next class John!
Mike Becker, Technical Services Instructor
Wow, thank you for confirming this lesson!
Observations to contemplate, when the car starts it does not start with one cycle of the engine, it starts at 3 cycles of the engine rotation.
When I turn the car off and walk around the gas compartment their is a definite smell of gasoline vapor round the back. It has a new cap greased up to better seal and pressurize, however it might be time to change the fuel filter?
Should I do a compression test for cylinder number 1 where I found lots of carbon build-up?
Alex, fuel smell could be coming from an component in the EVAP system. As for the carbon build up...you can do a compression test sure, but if the cars running ok, i'd leave it be. No sense in trying to find a problem that's not there.
Mike Becker, Technical Services Instructor
Hi miss Marie sent me too, send her the hat, I subscribed
Hey Bill, thanks and welcome!
Mike Becker, Senior Technical Instructor
What may be the cause of a 6 Cylinder engine with a lean condition on 1,2,3 cylinders and a rich condition on 4,5,6 cylinders?
Did i miss the rich code diagnostic?
Miss Marie sent me
Niceeeee!
Mike Becker, Senior Technical Instructor
Hi, My car is Corolla 2009 and it always appear the booth SYSTEM TOO LEAN (BANK 1) & SYSTEM TOO RICH (BANK 1) ... any help please ??
Hey Bashar, interesting that it has 2 codes stored that are the exact opposite. Start by looking at the fuel trims and see how it's running right now. From there it will give you a direction to go.
Mike Becker, Senior Technical Instructor
Linked from Young Marie at SMA.
What if bank 1 has negative 20 short and long trims and bank 2 has positive 20 short and long term trims
B is the answer, little late!
Better late than never Bernarda!!!
Mike Becker, Senior Instructor
You guys are the best.
Thanks William, we are only the best because we have the best viewers!
Mike Becker, Technical Services Instructor
I have a 5.3 chevy truck bank 1 is lean PO 171 and Bank 2 is rich PO 175 , would these two conditions be the O2 sensors ,MAF sensor ,or a leaky intake gaskets .I did the fuel pressure test ,its at 58 psi and holds pressure,i cleaned the MAF sensor but still comes up with a PO 171 bank 1 lean , PO 175 back 2 rich ,engine runs rough up until its at temp then it runs at idle not too bad but has no power when you step on the gas and back fires and when you bring up the RPM to around 2000 or so it runs really rough.
Brian, see if the 02's are doing their jobs. Force the rich side lean and the lean side rich. If they respond well then they are working. Does the issue get worse the hotter the engine gets? Maybe a plugged up cat issue?
Mike Becker, Senior Technical Instructor
Hi.. could u please help me on my question? When I opened my car bonnet I saw that my O2 sensor - ECU cable has been broken. However this was not shown as a CHECK engine alarm. Does it mean that my ECU does not function properly? Because in my car manual code 21 is for - At a speed of up to 100 km / h and a speed above 1500 rpm, the amplitude of the oscillations of the oxygen sensor OX (OX1) decreases to 0.35 - 0.70 V for a period of 60 s or more. So of my O2 sensor wire was disconnected this should be shown..please advice..
Vidura, unfortunately I am not sure what emissions standards your vehicle is set to. I would agree that an open circuit(wire broken) should set a check engine warning light.
Mike Becker, Technical Services Instructor
Great job !
Thank you very much!
Mike Becker, Senior Technical Instructor
do not understand why you had a lean condition on banks 1 and 2 when it was only bank 2
Tech B is right because when egr is stuck oxygen percentage detected by oxygen sensor is Comparatively high
But EGR is not oxygen, it's inert. So what does that do to our oxygen content? And what do you mean by it reading high? Like high voltage?
Mike Becker, Technical Services Instructor
Thank for the video. Could you help me make sense of these STFT and LTFT values. I have 07 ford taurus, for bank 1 STFT stays between +/-3%, but LTFT stays constant at about -12% at Idle. Bank 2 is lean at idle with +12% total fuel trim. When I increase RPM to 2500, STFT jumps between +/-6% and LTFT stays constant at -19%. Bank 2 improves at 2500 RPM with about +6% total fuel trim. OBD says cylinder 1,2, and 6 misfire. I have tested injectors, replaced the leaking injector already. What do these trim value mean? How come bank 1 is rich and bank 2 is lean? Thank you.
Does the engine have any other trouble codes? Something is causing the engine to run lean on one and rich on the other bank. Has the timing chain ever been off?
Mike Becker, Senior Technical Instructor
@@GoTechTraining Thanks for the response. Currently, I only get 1,2,6 cylinder misfire codes when I erase the codes. In October 2019, after I reset ECM by disconnecting battery terminal, I did get P0420 and P0430 pending codes saying "catalyst system efficiency below thresold for both banks". I checked freeze frame data screenshots I took that time. LTFT on bank 1 was -14.1, and +3.1 on bank 2. STFT 1 was -1.6 and STFT2 was +1.6. From research, the rich condition on bank1 and lean condition on bank 2 eliminates some possibilities like vaccum leak, bad MAF, leaking egr valve, ECT sensor, fuel pressure regulator. there might be vaccum leak on just bank 2 but I am not sure how that could be possible since both banks are fed same way.
So for rich condition, the remaining culprits are:
1) bad O2 sensor O2S1B1 (which seems to be working since it jumps between 0.1-0.85V)
2) Spark plugs on bith banks (I replaced spark plugs in December last year, so I am not sure if its bad, I am planning to check them tomorrow).
3) leaking fuel injectors (less likely because, when I saw cylinder 1,2 misfire last time I swapped them with cylinder 4,5, now there is still cylinder 1,2 misfire)
4) Catalytic converter (not sure since there is no rotten egg smell, just exhaust fume out of tail pipe)
5) Exhaust leak (I smell exhaust fume in cabin whenever I start AC or heater, I think there is exhaust leak. I have to check both banks exhaust system for leak, but not sure whether it should cause rich or lean condition)
Do you think the exhaust leak is due to plugged catalytic converter? Do you think its the main culprit? Please let me know if I am checking things right way. Thank you very much
Pour a Fosters stubbie in the tank for an extra 20KWs!.Ha Ha. In Australia it was a Holden Monaro by the way.
Gotta get that extra power any way you can right? Ahhh a Monaro. I knew Holden made it, just couldn't remember the model name. Thanks tecnaman!
Mike Becker, Technical Services Instructor
I have done all this and still have code what else is there that could make this code supercharger valve or what
Check out the video I have with the Audi, it shows some more stuff you can check out.
Mike Becker, Senior Technical Instructor
What do you check if the BARO is not correct? Hyundai Tucson we were looking at had P0171 & P0174 and no vac leaks and BARO was showing 23inHg with KOEO and with vehicle running (local BARO 30inHg)...no change when unplugging the IAT or MAF sensor...could not located a specific BARO sensor on the vehicle and ALL-Data did not show a sensor location (i believe it is integrated into the MAF). 2008 Hyundai Tucson 2.7L. The PCM was adding as much as 25-31.8% on both Banks...sometimes was throwing a P0170 & P0173 code also.
I actually can't remember if I was monitoring the BARO PID when I unplugged the MAF. I should also add that vehicle seem to run worse with MAF unplugged, and no noticeable change in running condition w/ IAT unplugged. All 4 O2 sensors seemed to be working correctly from the live data but sometimes seemed slow to respond. No O2 sensor codes tho, and that may have been my tablet just running slow on updating the live data which it seems to do if I am graphing 4 PIDS at once. All 4 oxygen sensors showed close to 450mV w/ KOEO. They were usually like ~410-430mV actually. When you fire it up, the upstreams do start switching when it enters CL but the downstreams go hard lean then the STFT go hard positive +31% then as the LTFT pick up the slack the STFT drop to +10-15% ish. Everything in my experience was pointing towards vacuum leak but we checked with spraying carb cleaner w/ engine running near potential vac leak areas as well as testing for vac leaks w/ a smoke machine...neither way found any leaks. I thought maybe low fuel pressure, because it something affecting both banks. Unfortunately my scan tool wont pull fuel rail pressure data and the vehicle does not appear to have a typical schrader style valve to test the pressure directly. After one of the many times of clearing and resetting everything during 2 days of testing it just didn't do it, it didn't pull any codes, the fuel trims all seemed good. And no CEL, i was shocked... So i went and test drove it and the readiness monitors were checking off one by one and I thought, IDK this thing might have just fixed itself. I only needed 1 more readiness monitor to get it to pass SI (you can have 1 not ready, it had 2) and before either of them popped to ready....dayum MIL came back on and pulled System too lean bank 1 & 2 again. This one is really giving me trouble, if anyone can help.
I checked and found a TSB about the air intake box sometimes being an issue, followed TSB instructions and verified it was not our problem...we did other testing too that I am sure I can't remember right now...but any input from anyone would really be appreciated. I am at a total loss here.
Miss Marie from SMA sent me
Niceeeeee!
Mike Becker, Senior Technical Instructor
Question: Would short term fuel trim change while in open loop with the propane near the leak? Or does short term fuel trim only kick in once closed loop starts after the car runs for a bit?
Neil, when a car is in open loop its fuel off of base maps that are in the PCM. Closed loop is when fuel trimming occurs. Short term fuel trim will normally read 0 when in open loop.
Mike Becker, Senior Technical Instructor
necesitamos otro video en espanol me ha sido de mucha ayuda gracias por sus ensenanzas
Hola Celerino, Estamos haciendo esta misma clase en español LIVE el miércoles, 19 de abril a las 11am y 2pm hora central. Espero que te veamos allí.
Mike Becker, Technical Services Instructor
Excellent vid as usual.
Wee Q. Instead of using propane to see a reaction from the o2 sensors could I use acetylene from the garages oxyacetylene? And also, can I put oxygen in intake to lean-off mixture in when o2 is reading rich to confirm o2 is reading properly?
Thanks.
N/W Scotland.
Fox Brendon, I have heard of people using acetylene, just be SUPER careful. I prefer propane, or even brake clean. As for running it lean, just pull a vacuum hose. It will suck tons of air in and then you can see if it will skew lean. No need to force 02 into it.
Mike Becker, Senior Technical Instructor
It runs great in park but put in gear and it sputters
Marie sent me too!
Nice!!!!
Mike Becker, Senior Technical Instructor
Nice job Mike
Thanks man!
help 2003 jag x type 3.0 awd. hesitation at low load and low revs fine flat out etc. changed bank 1 o2 sensor 5 times and throws 5 different fault codes.that sensor related, now its a lean code on that bank fuel trim all over the place also. done all vacuum checks changed inlet manifold , injectors, plugs, coils, maf, map, throttle position sensor, throttle body still the same, with a one of faulty o2 sensors p1646 runs fine but all others nope..... wtf!!!!!
Hey John, sounds like you have yourself quite a headache here. Have you checked fuel pressure? That can cause an issue. What does the short and long term trims read?
Mike Becker, Senior Technical Instructor
Hello Mike,
It appears that the on board diagnostic tool tester for codes has to be cleared of old codes and the car's pcm computer has to reboot by disconnecting the negative terminal and reconnecting it so that the check engine light disappears. The tester says no codes and the trims are at 0, long term and shor term hover around the zero mark when in idle long term is slightly at -3 and the short trim at -3. Is that a good fix?
Alex, sounds fixed to me! Typically anything you see around 0 is good. You want to for sure see under +/- 10 for the trims. I think it's all fixed up!
Mike Becker, Technical Services Instructor
47:10 chunk missing,another chunk missing... bad material, the money light on, and people pay good money for this;
Also, you have to make absolutely sure that those "blue" rings stay well captioned in their nests when you assemble the whole shibang,you can't see them as you lower the manifold;
Yeh, you have to be super careful with them, they like to move around a bunch.
Mike Becker, Senior Technical Instructor
good job man
Thanks Nadeem!
Mike Becker, Senior Instructor
Omg! Hit pause and go turn off that alarm!
Hard to pause a live video....should have went to a commercial break ;)
Mike Becker, Senior Technical Instructor
Hello Mike, I have a question about the fuel test. You demonstrated how check alcohol content in the sample of gasoline. I understand the process and your results. My question is about same test telling you if your sample has a high water content. I would think you fill the container 100ml of gasoline and 20 ml of the water with food coloring. If the fuel was contaminated with too much water. Would the 20 ml section grow in the sample?
Hi Joseph, Yes, the water value would increase. Say the fuel was 20% water..you should see 80ml of fuel then and 40ml of water. The water and alcohol will look and mix the same.
Mike Becker, Technical Services Instructor
Hello from utah miss Marie sent me
Hey Juan, Welcome!
Mike Becker, Senior Technical Instructor
Ms Marie sent me!
Sweeeeet!
Mike Becker, Senior Technical Instructor
@@GoTechTraining I love your teaching presentations. I'm not in the business but I do most of my own work. I'm 64 and I want to know what to look for and how to diagnose. You guys are the best!
Thanks so much Paul! Don't hesitate to ask questions if something wasn't clear. I'm here to help :)
Mike Becker, Senior Technical Instructor
@@GoTechTraining thank you so much! BTW, I'm a NGK freak. I work in a Yamaha and Suzuki shop as a young person. The best plugs out there!
I'm trying to get my head around fuel trims. Would I be correct that a vacuum leak would cause the engine to run at a higher idle speed than normal? My logic says it would, but I've never heard of a high idle speed being a symptom of a vacuum leak before. Thanks for your help.
I believe your logic is correct, unmetered air at idle increases fuel delivery from pcm trying to reach 14.7:1 stoichmetric ratio which increases idle.
hello from australia
Hello from Wisconsin Helen!
Mike Becker, Senior Technical Instructor
Stuck open will not allow for true evaluation of the condition, likely showing lean,barring any other condition, based on blow by
Marie sent us...
Nice!!!!!
Mike Becker, Senior Technical Instructor
Marie sent me from south main auto.
Nice!!!
Mike Becker, Senior Technical Instructor
Those intake gaskets look poor quality ! Are they OEM?
Can't remember Joe. They worked though.
Mike Becker, Senior Technical Instructor