Part throttle tuning
Part throttle tuning I'm about to jump head first into edit and try to get my car tuned now that I can drive it (seasonal tags). I did some logs yesterday but don't think I logged some of the stuff I needed in order to be able to accurately change values in edit. My ltrims at part throttle are averaging between -14 & -12. So I know I'm pig rich, and it smells like a gas station at the back of the car <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> So what exactly do I need to monitor? Obviously ltrims, and then maf frequency, fuel cell, and rpm? Will that get me what I need? Trying to log only what I need as to get better refrsh rates.
I know I need to do my part throttle tuning in maf tables, and see that the numbers are in Gm/sec. How do I go about converting my ltrim #'s to gm/sec so I know what changes to make? Or am I looking at the wring table in edit?
I know I need to do my part throttle tuning in maf tables, and see that the numbers are in Gm/sec. How do I go about converting my ltrim #'s to gm/sec so I know what changes to make? Or am I looking at the wring table in edit?
Staging Lane
Joined: Feb 2002
Posts: 97
Likes: 0
From: Newport, Michigan
Re: Part throttle tuning Along with what you said to log, you can also log the MAF flow rate in gm/sec,,, so no conversion is needed.
One fine point, with the LTFTs running at -12 to -14% factored in by the PCM, you should be averaging a perfect 14.7:1 AFR at part throotle.
So your car should not smell like its rich unless its rich at WOT.
One fine point, with the LTFTs running at -12 to -14% factored in by the PCM, you should be averaging a perfect 14.7:1 AFR at part throotle.
So your car should not smell like its rich unless its rich at WOT.
Re: Part throttle tuning A modestly rich vehicle won't smell like gasoline.
High HC emissions tend to come from over-lean
while rich makes more CO.
If you're smelling the tailpipe, presumably
this is at idle anyway. Cold idle isn't
closed loop I think.
One thing about tailpipe smells - if you have
any significant asymmetry between fuel injector
flow the PCM will control for the bank average
and this will mean one cylinder can be way lean
and 3 slightly rich, etc. - whatever makes it
all add up right. So you can have a good O2
voltage and every cylinder at a nonideal mix
if this fundamental assumption of identical
cylinder operation is invalidated.
High HC emissions tend to come from over-lean
while rich makes more CO.
If you're smelling the tailpipe, presumably
this is at idle anyway. Cold idle isn't
closed loop I think.
One thing about tailpipe smells - if you have
any significant asymmetry between fuel injector
flow the PCM will control for the bank average
and this will mean one cylinder can be way lean
and 3 slightly rich, etc. - whatever makes it
all add up right. So you can have a good O2
voltage and every cylinder at a nonideal mix
if this fundamental assumption of identical
cylinder operation is invalidated.
