MAF Airflow Rate
#1
#2
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EsRay (01-25-2018)
#3
Hello Michael,
Thank you for your reassuring reply. I will take a look at my driving MAF numbers as well.
I am just casting about, really......I have somewhat lopsided Fuel Trims, with Bank 2 fine and dandy, showing small movements in LTFT to keep STFT to around zero, but bank I appears to need a higher LTFT and still fails achieve the same objective (STFT stays in low-ish negative territory despite LTFT of 6% plus)?
For your interest, I gave up trying to figure out whether my PCV valve was functioning correctly or not and replaced it! I have also fitted an Oil Catch-Can to try to overcome my periodic clouds of grey smoke. I will post with results when I have them, but so far, so good!!
Thanks to the fantastic help I have enjoyed on this forum from a number of members like yourself, I now have NO DTC's, but I still have a slight tremble and shake at idle and my Timing Chain Tensioners are going to be my next fixation!
Regards,
Ray
Thank you for your reassuring reply. I will take a look at my driving MAF numbers as well.
I am just casting about, really......I have somewhat lopsided Fuel Trims, with Bank 2 fine and dandy, showing small movements in LTFT to keep STFT to around zero, but bank I appears to need a higher LTFT and still fails achieve the same objective (STFT stays in low-ish negative territory despite LTFT of 6% plus)?
For your interest, I gave up trying to figure out whether my PCV valve was functioning correctly or not and replaced it! I have also fitted an Oil Catch-Can to try to overcome my periodic clouds of grey smoke. I will post with results when I have them, but so far, so good!!
Thanks to the fantastic help I have enjoyed on this forum from a number of members like yourself, I now have NO DTC's, but I still have a slight tremble and shake at idle and my Timing Chain Tensioners are going to be my next fixation!
Regards,
Ray
Last edited by EsRay; 01-25-2018 at 09:12 AM.
#4
I wouldn't suspect MAF if you have a bank-to-bank difference. That would affect both banks equally.
So if I understand, on bank 2 you have 0% LTFT and STFT oscillates as expected. But bank 1 you have a +6% LTFT and -3% STFT? That would give a total trim of 3%, indicating the PCM is trying to enrich the mixture slightly.
If that's correct, I wouldn't worry too much. The long term trims will come in line eventually so STFT hovers around zero. +/- 3% is really well within the tolerance of a normal engine. Beyond 10% you should be concerned. The PCM won't set any codes until total trim gets to approx. 25%. However, if you want to figure out a slight leak, I would get the engine smoke tested.
For your idle shake, have you looked at the motor and trans mounts? I had mine go bad around 60k miles. They don't last very long as they are the hydraulic type with a liquid in the center. I would do all 3 if you suspect one, I had to do mine in series every 5-10k miles, should have just done them all at one time.
So if I understand, on bank 2 you have 0% LTFT and STFT oscillates as expected. But bank 1 you have a +6% LTFT and -3% STFT? That would give a total trim of 3%, indicating the PCM is trying to enrich the mixture slightly.
If that's correct, I wouldn't worry too much. The long term trims will come in line eventually so STFT hovers around zero. +/- 3% is really well within the tolerance of a normal engine. Beyond 10% you should be concerned. The PCM won't set any codes until total trim gets to approx. 25%. However, if you want to figure out a slight leak, I would get the engine smoke tested.
For your idle shake, have you looked at the motor and trans mounts? I had mine go bad around 60k miles. They don't last very long as they are the hydraulic type with a liquid in the center. I would do all 3 if you suspect one, I had to do mine in series every 5-10k miles, should have just done them all at one time.
#5
#6
Ray,
It would be a good idea read the fuel trim primer document, located here
https://www.jaguarforums.com/forum/g...17/#post304460
It explains a lot but if have any questions or need something explained let us know.
Cheers
34by151
It would be a good idea read the fuel trim primer document, located here
https://www.jaguarforums.com/forum/g...17/#post304460
It explains a lot but if have any questions or need something explained let us know.
Cheers
34by151
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