IDLE provblems in gear...
05-10-2004, 12:02 AM
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IDLE provblems in gear... In reverse and drive when comming to a stop the car goes from around 5-600rpms to like 200 and dies out. I just got done putting the vig3800 stall in and long tube headers off road pipe and everything. What kinda tunes are you all running? anyone out there with the same setup and mind sending me a file for ls1edit to use. or just go get it tuned around here? thanks guys.
05-10-2004, 07:42 AM
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The converter lost you some "ballast" and the headers
probably magnified some low-end volumetric efficiency
error that affects idle fuel calculations (the MAF being
pretty sloppy down low).
To fight the bounce & crash coming down from cruise
you might want to play with the throttle cracker /
throttle follower decay settings, make it settle slower
the first time and it might not get to undershooting
so badly.
To fight continuous idle bounce most of the cam /
headers guys seem to end up scaling the VE table in
the 400RPM and 800RPM colums (which bracket the
target idle RPM) by something like 0.80 and 0.90
multiplication. However this can be a "fussy" fit and
you might just want to ease into it slow, like keep
multiplying them by 0.97 over and over until it gets
smoother. This is a quickie w/ HPTuners, I guess it
might be a drag with a slower tool. You could prepare
a batch of files that only change this one thing ahead
of time and then stuff them sequentially until you find
one worth keeping.
Also setting idle up a bit gives it more "headroom". I
put mine to 650RPM and have only started shaving on
my VE, I have a smaller converter so my bounce is not
terrible, just annoying cold. It got learned out to some
extent but was heinous the first week or two after the
TC install (would even stall in the median)
probably magnified some low-end volumetric efficiency
error that affects idle fuel calculations (the MAF being
pretty sloppy down low).
To fight the bounce & crash coming down from cruise
you might want to play with the throttle cracker /
throttle follower decay settings, make it settle slower
the first time and it might not get to undershooting
so badly.
To fight continuous idle bounce most of the cam /
headers guys seem to end up scaling the VE table in
the 400RPM and 800RPM colums (which bracket the
target idle RPM) by something like 0.80 and 0.90
multiplication. However this can be a "fussy" fit and
you might just want to ease into it slow, like keep
multiplying them by 0.97 over and over until it gets
smoother. This is a quickie w/ HPTuners, I guess it
might be a drag with a slower tool. You could prepare
a batch of files that only change this one thing ahead
of time and then stuff them sequentially until you find
one worth keeping.
Also setting idle up a bit gives it more "headroom". I
put mine to 650RPM and have only started shaving on
my VE, I have a smaller converter so my bounce is not
terrible, just annoying cold. It got learned out to some
extent but was heinous the first week or two after the
TC install (would even stall in the median)