Reset LTRIMS...will it knock until trims are re-learned?
06-22-2004, 09:28 AM
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Reset LTRIMS...will it knock until trims are re-learned? I am getting some weird inconsistent knock retard after changing my tune and resetting LTRIMS. I have not bumped up my timing above 1200 rpms any above stock. Can you get a lean knock until the computer figures it out? Log attached if you want to look at it. (PLEASE LOOK)
The LTRIMS are positive while I try to stabilize them.
The LTRIMS are positive while I try to stabilize them.
06-22-2004, 09:38 AM
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IMHO I think this would only hold true if you were running lean and the PCM had to add fuel to meet the desired AFR. If you were at a place where you were running - LTRIMS then i dont see why resetting it (0) would make it knock
06-22-2004, 09:50 AM
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Any time the PCM is flashed, it then needs a good 40 minutes of drive time using all engine conditions for the LONG TERM trims to get re-averaged.
LTFTs are only acted on by PCM once every 10 minutes so never go by the values until you have enough relearn time.
A good clue the trims are relearned is the short term values in the beginning will be jumping all around, as PCM averages trims out they short term values will change much slower.
Your scanner showed in that drive the long terms are 13% too lean and up to 10 degrees of timing yanked due to knock.
Your left STFT went 21% lean while right was 14% lean.
LTFTs are only acted on by PCM once every 10 minutes so never go by the values until you have enough relearn time.
A good clue the trims are relearned is the short term values in the beginning will be jumping all around, as PCM averages trims out they short term values will change much slower.
Your scanner showed in that drive the long terms are 13% too lean and up to 10 degrees of timing yanked due to knock.
Your left STFT went 21% lean while right was 14% lean.
06-22-2004, 01:44 PM
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Originally Posted by Team ZR-1
Any time the PCM is flashed, it then needs a good 40 minutes of drive time using all engine conditions for the LONG TERM trims to get re-averaged.
LTFTs are only acted on by PCM once every 10 minutes so never go by the values until you have enough relearn time.
A good clue the trims are relearned is the short term values in the beginning will be jumping all around, as PCM averages trims out they short term values will change much slower.
Your scanner showed in that drive the long terms are 13% too lean and up to 10 degrees of timing yanked due to knock.
Your left STFT went 21% lean while right was 14% lean.
LTFTs are only acted on by PCM once every 10 minutes so never go by the values until you have enough relearn time.
A good clue the trims are relearned is the short term values in the beginning will be jumping all around, as PCM averages trims out they short term values will change much slower.
Your scanner showed in that drive the long terms are 13% too lean and up to 10 degrees of timing yanked due to knock.
Your left STFT went 21% lean while right was 14% lean.
06-22-2004, 02:12 PM
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You may also see your timing slide down, if you still
have a low octane table with "mellower" settings than
the high octane spark table. That may kill the knock
before LTFTs get settled, even. And take its own
sweet time about coming back out.
I think the "Knock Learn Factor" PID may show you
what's up, with that (but haven't played with it in
HPTuners logging, yet).
have a low octane table with "mellower" settings than
the high octane spark table. That may kill the knock
before LTFTs get settled, even. And take its own
sweet time about coming back out.
I think the "Knock Learn Factor" PID may show you
what's up, with that (but haven't played with it in
HPTuners logging, yet).
06-22-2004, 02:23 PM
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Originally Posted by Another_User
That's what I got out of it too...so that is what probably caused the knock right?
Being in that run you only went to like 2500 RPMs for WOT and the timing was 25 degrees I would slant to you do not have enough injector if after the PCM relearn and your still 13% too lean.
I'd shoot for like 28 degrees timing at WOT if you have the fuel flow to support it.
06-22-2004, 02:58 PM
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Originally Posted by Team ZR-1
If you had done enough driving time for the PCM relearn and still are that lean then it is valid knock and you need more fuel flow, if you cannot adjust injector pulse width to be on longer then injectors 9 out of 10 times are too small for the engines ability.
Being in that run you only went to like 2500 RPMs for WOT and the timing was 25 degrees I would slant to you do not have enough injector if after the PCM relearn and your still 13% too lean.
I'd shoot for like 28 degrees timing at WOT if you have the fuel flow to support it.
Being in that run you only went to like 2500 RPMs for WOT and the timing was 25 degrees I would slant to you do not have enough injector if after the PCM relearn and your still 13% too lean.
I'd shoot for like 28 degrees timing at WOT if you have the fuel flow to support it.
