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Roger Ramjet · 07-10-2009, 10:49 PM

From the AFR it looks like the dyno operator didn't apply full throttle until after 4000 RPM. Up till that point the PCM was in closed loop at 14.7 AFR. At full throttle (open loop) the PCM commanded a very rich AFR. I suspect this is from the LTFTs being jacked way up and applying this fuel increase to the full throttle fuel table.

My opinion is that this engine has an intake air leak somewhere causing the LTFTs to trim up.

07-10-2009, 10:49 PM	#142
Roger Ramjet Motor Head Drives: CTS-V Join Date: Feb 2009 Location: So MD Posts: 494	From the AFR it looks like the dyno operator didn't apply full throttle until after 4000 RPM. Up till that point the PCM was in closed loop at 14.7 AFR. At full throttle (open loop) the PCM commanded a very rich AFR. I suspect this is from the LTFTs being jacked way up and applying this fuel increase to the full throttle fuel table. My opinion is that this engine has an intake air leak somewhere causing the LTFTs to trim up. __________________ History Camaro's: 83, 93, 95, 98, & 10.