Why is maf making the car lean
12-13-2005, 12:30 PM
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Why is maf making the car lean At the dyno today i got the ve table dialed in with speed density. got a base speed density tune with just stock timing and got some kr with a 12.9 afr. So i figured i would plug the maf back in and see if it got rid of the kr well it did but it made the afr go up to 15. The only thing i changed was the maf in between pulls. Anyone have an idea why this might be? 
Also the car is not the one in sig its a heads and cam car with bolt ons.
Also the car is not the one in sig its a heads and cam car with bolt ons.
12-13-2005, 01:09 PM
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It wasnt an after market maf it was the same one i have unpluged it before to make some sd runs at the track and it didnt mess up then even when i changed things in sd and went back to maf.
12-13-2005, 04:24 PM
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what are your fuel trims like after you put the maf back on?
MAF is likely outta calibration ... once you SD tune a car... if you want to use the mAF it's generally a good idea to recalibrate the MAF tables
MAF is likely outta calibration ... once you SD tune a car... if you want to use the mAF it's generally a good idea to recalibrate the MAF tables
12-13-2005, 09:35 PM
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It does repeat and I only dialed in the wot cells on the dyno so fuel trims wont really help. I am only concerned with wot on the dyno i will do the rest on the road later we can just get dynotime for cheap now.
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12-14-2005, 08:29 AM
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OK thanks guys looks like im in for some fun today geting this thing calibrated then i wish it was my car i would just run sd. Thanks for the help on what was obviously a stupid question.
12-18-2005, 09:01 PM
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I'm still confused about how to calibrate the maf. I'm using hptuners and innovate. But i've been reading and still not sure how to do it. Can anybody help my sd open loop tune is almost done
12-19-2005, 03:27 PM
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On older (98-00?) F-bodies there are two VE tables.
The secondary is what you run on, with the MAF
unplugged (or other MAF fault). The Primary is what
you run on when things are right. If you are doing
VE table tuning with the MAF out, the Primary has
to be built from the Secondary when you're done
(filling in the "missing" lines by interpolation).
With the MAF plugged in, above 4KRPM the car is
running off the MAF entirely and "mostly MAF" for
a ways below that. The MAF may be lying, or it
could be that you have tuned up speed density to
embody some correction for -other- error, but the
MAF table has not been tweaked to the same end.
Any other (like fuel delivery, injector flow, fuel
pressure, etc.) issues / mods you know of? Is the
WOT AFR -consistently- 15:1 or just at the upper
end (i.e. can you see any sign of fuel fade, or is
this purely a sensor / commanded fueling problem)?
The secondary is what you run on, with the MAF
unplugged (or other MAF fault). The Primary is what
you run on when things are right. If you are doing
VE table tuning with the MAF out, the Primary has
to be built from the Secondary when you're done
(filling in the "missing" lines by interpolation).
With the MAF plugged in, above 4KRPM the car is
running off the MAF entirely and "mostly MAF" for
a ways below that. The MAF may be lying, or it
could be that you have tuned up speed density to
embody some correction for -other- error, but the
MAF table has not been tweaked to the same end.
Any other (like fuel delivery, injector flow, fuel
pressure, etc.) issues / mods you know of? Is the
WOT AFR -consistently- 15:1 or just at the upper
end (i.e. can you see any sign of fuel fade, or is
this purely a sensor / commanded fueling problem)?
12-19-2005, 05:08 PM
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12-19-2005, 05:11 PM
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Try the sticky:
*READ ME FIRST-- Tuning Docs,VE/MAF, SES Lights, FAQS!!!! + more! *12/07/05*
in this section or https://ls1tech.com/forums/pcm-diagnostics-tuning/256989-dialing-maf-tables-anyone.html
*READ ME FIRST-- Tuning Docs,VE/MAF, SES Lights, FAQS!!!! + more! *12/07/05*
in this section or https://ls1tech.com/forums/pcm-diagnostics-tuning/256989-dialing-maf-tables-anyone.html
