HELP! trans acting up after cam install
09-03-2008, 09:07 AM
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HELP! trans acting up after cam install Well I had a 228 .573 lift 112 lsa cam in the car before. I wanted to go bigger. I purchased a bigger cam, to the effect of 242/244 duration .610 lift on a 112. My trans is a basically stock 4l60e with a shift kit & fuddle 4000. Cam install went great over this past weekend. When cruising around, my trans shifts sometimes almost on top of each other and occassionally if i jump on it, it goes through the gears like it's supposed and other times it won't rev passed like 3500 rpms at WOT. I'm *assuming* this is a tuning issue though i suppose anything is possible. I did find this thread: https://ls1tech.com/forums/showthrea...shifting+after
Can anyone tell if that solution may work in my application? If not, what else could be my problem here? Any help is greatly appreciated. Thanks.
Can anyone tell if that solution may work in my application? If not, what else could be my problem here? Any help is greatly appreciated. Thanks.
09-03-2008, 09:45 AM
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Begin with measuring the WOT TPS voltage with the
blade cranked full open at the TB, key on, engine off.
If it exceeds 4.75V you can get this sort of short-shift
behavior (a fail-safe mode for a TPS fault). A bump-
stopped TB or an aftermarket where the stop can be
adjusted too far over center, can do this.
blade cranked full open at the TB, key on, engine off.
If it exceeds 4.75V you can get this sort of short-shift
behavior (a fail-safe mode for a TPS fault). A bump-
stopped TB or an aftermarket where the stop can be
adjusted too far over center, can do this.
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09-03-2008, 04:01 PM
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I don't think the cam accounts for short shifting. The
shiftpoints (aside from fault modes) are set for MPH and
TPS (or RPM at WOT).
Airflow errors (MAF or VE) come in on the line pressure
via the "delivered torque - trans" computation but no
hook from that to the shift decision, just how smartly
it gets done and whether it slips.
shiftpoints (aside from fault modes) are set for MPH and
TPS (or RPM at WOT).
Airflow errors (MAF or VE) come in on the line pressure
via the "delivered torque - trans" computation but no
hook from that to the shift decision, just how smartly
it gets done and whether it slips.
09-04-2008, 08:47 AM
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You should get it tuned for the new cam but its probly not the problem your having with the tranny shifting though. Check what jimmyblue siad and make sure that the throtle cable is solidly in the hook for it and not poping out a little bit.