postive LTRIMS at WOT??
postive LTRIMS at WOT?? I take you would tune these in the PE vs RPM table?
Im trying to figure out what to do with my LTRIMS at WOT. at idle and cruising they mainly stay -3 or so... but i get jumps up to +3 to 4 with slight throttle off and on. When I WOT the car the B2 LTRIM jumps to +7 to +9 and the B1 side stays around 0 to +3
any ideas whats going on here? Do I need to add a little fuel say above 3600rpms??
Im trying to figure out what to do with my LTRIMS at WOT. at idle and cruising they mainly stay -3 or so... but i get jumps up to +3 to 4 with slight throttle off and on. When I WOT the car the B2 LTRIM jumps to +7 to +9 and the B1 side stays around 0 to +3
any ideas whats going on here? Do I need to add a little fuel say above 3600rpms??
Re: postive LTRIMS at WOT?? </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Doc99SShome:
<strong> . . .
It appears that for your car, the WOT LTFT is coming from the last non-WOT fuel cell because your idle and just off idle LTFTs are 0% or negative. . . </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif"> </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by 98TAauto:
<strong> . . . at idle and cruising they mainly stay -3 or so... but i get jumps up to +3 to 4 with slight throttle off and on. . . </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Dude, are you averaging your Lterms in fuel cells 4 thru 16 during a long autotap log?
This statement kinda sounds like you're looking at real-time readings and not over-all average. I just wanna be clear on this issue <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Idle with the A/C off is cell 19 and cell 18 with A/C on.
I wouldn't use these cells to tune your Lterms. Tune them with 4-16, give 'em some learning miles eg. 40, and then see what happens at WOT <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
If you're still showing values then Doc's method should be attempted next <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" />
<strong> . . .
It appears that for your car, the WOT LTFT is coming from the last non-WOT fuel cell because your idle and just off idle LTFTs are 0% or negative. . . </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif"> </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by 98TAauto:
<strong> . . . at idle and cruising they mainly stay -3 or so... but i get jumps up to +3 to 4 with slight throttle off and on. . . </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Dude, are you averaging your Lterms in fuel cells 4 thru 16 during a long autotap log?
This statement kinda sounds like you're looking at real-time readings and not over-all average. I just wanna be clear on this issue <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
Idle with the A/C off is cell 19 and cell 18 with A/C on.
I wouldn't use these cells to tune your Lterms. Tune them with 4-16, give 'em some learning miles eg. 40, and then see what happens at WOT <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />
If you're still showing values then Doc's method should be attempted next <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" />
Staging Lane
Joined: Feb 2002
Posts: 97
Likes: 0
From: Newport, Michigan
Re: postive LTRIMS at WOT?? You do not tune LTFTs at WOT with the PE vs RPM table.
The LTFT value at WOT comes from the LTFTs while you are at part throotle. I do not know exactly how the WOT LTFT is calculate by the PCM, but it may come from the higher engine load case (fuel cell) locations. (Or maybe an average of them all).
It appears that for your car, the WOT LTFT is coming from the last non-WOT fuel cell because your idle and just off idle LTFTs are 0% or negative.
I recommend that you record several part throotle runs going up thru the gears and data log MAF frequency, MAF flow rate, engine rpm, LTFT, fuel cell, and matbe a couple more of your interest.
I predict that you will discover that the middle part of the MAF table is under-reporting the actual air flow inti the engine. This will create positive LTFTs at the higher part throotle engine load case while the idle and just off idle is OK.
IF you want to tune only the PE vs RPM table, you can take out the 7% to 9% extra fuel that is coming in at WOT due to the positive LTFT values. But if you do this and in the near future the LTFT at WOT is lower for any reason, you could be running too lean at WOT.
The LTFT value at WOT comes from the LTFTs while you are at part throotle. I do not know exactly how the WOT LTFT is calculate by the PCM, but it may come from the higher engine load case (fuel cell) locations. (Or maybe an average of them all).
It appears that for your car, the WOT LTFT is coming from the last non-WOT fuel cell because your idle and just off idle LTFTs are 0% or negative.
I recommend that you record several part throotle runs going up thru the gears and data log MAF frequency, MAF flow rate, engine rpm, LTFT, fuel cell, and matbe a couple more of your interest.
I predict that you will discover that the middle part of the MAF table is under-reporting the actual air flow inti the engine. This will create positive LTFTs at the higher part throotle engine load case while the idle and just off idle is OK.
IF you want to tune only the PE vs RPM table, you can take out the 7% to 9% extra fuel that is coming in at WOT due to the positive LTFT values. But if you do this and in the near future the LTFT at WOT is lower for any reason, you could be running too lean at WOT.
