i have a 2001 burb that needs tuning in a bad way. it is stock except for a KN filter kit and duel exhaust. pcm pulls gobs of timing on tip in and on hard acceleration (15 to 20deg). boggs baddly on accel and sometimes surges back and forth. tune is stock. kR about 5 deg at most. run 93 oct and 180deg thermostat. I was a mechanic in a former life so i understand whats going on. just not sure where to start.
tune and log 2001 chevy suburban 8.1, 4L80E OEM tune
Files as requested. I might add that temp and humidity were low this morning. Increasing temperature seems to make it worse (IAT). Also, in my youth I had plenty of oportunities to work on non ecm equipped cars and I could tell right away it was a timing issue before I ever purchased HPT. Used a scan tool to confirm my suspicion. Hope this helps. Running 93 octane.
Confirmed the tune is stock. Log shows calling for a lot of fuel. Are you sure there's nothing wrong with fuel flow or vacuum leaks? Dirty MAF sensor? Non-stock fuel injectors? Fuel pressure problem? Wouldn't want to tune around a problem.
Last edited by SiriusC1024; 06-09-2023 at 05:42 AM.
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