Random idle surge on '98 LS1 *Tune/log attached*
12-20-2011, 10:44 PM
#1
Random idle surge on '98 LS1 *Tune/log attached* I have a random idle surge on my '98 Z28. It will idle fine, then randomly start surging and won't recover until I blip the throttle. My last tune was done in 2005, and this problem has slowly gotten worse since then. I just now got HPT so I'm trying to figure out how to see the cause and effect using my tune and the scanner.
Mods are h/c/i/e/4600 stall. Cam is only a 230/234 111 LSA.
Below you'll find my tune and log. Let me know if you see any out of the ordinary parameters.
Mods are h/c/i/e/4600 stall. Cam is only a 230/234 111 LSA.
Below you'll find my tune and log. Let me know if you see any out of the ordinary parameters.
12-22-2011, 09:33 AM
#3
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I would set it up and scan, my suspicion is that this is trim
creep as the exhaust cools and your throttle blip is putting
the O2 sensors temporarily back to working right (or right
enough) by nulling the STFTs (leaving idle cell) and reheating
sensors and relieving the drifted-rich STFTs.
If you see STFTs (or even LTFTs) creep after returning to idle
over the course of some seconds, this is your exhaust heat
problem.
creep as the exhaust cools and your throttle blip is putting
the O2 sensors temporarily back to working right (or right
enough) by nulling the STFTs (leaving idle cell) and reheating
sensors and relieving the drifted-rich STFTs.
If you see STFTs (or even LTFTs) creep after returning to idle
over the course of some seconds, this is your exhaust heat
problem.
