So I had my installer install an ECS super charger kit on my all stock 2008 C6 6spd Z51 with only 20k on the clock. Installed the tune and everything was great. Ran the car for about 10 miles and the check engine light comes on so I bring it back in. He checks it for any mechanical errors or anything that needs adjusted, leaks, maf, throttle body,, O2's were performing well, smoke test etc... No problems, everything checked out A-OK but says that something changed in the tune and the ecu is adding more fuel to compensate for the lean notification running lean in banks 1 and 2. So my question is how does that happen after a tune is already installed and everything is running fine and nothing is found to be out of sorts with the engine, the pcv or any other issues involved. Doug if you're out there maybe you could chime in since I bought this kit off of you and maybe you've had issues like this in the past with your tuners? I'm actually on my way to pick it up now because he said he has resolved the issue by remapping the tune And all fuel trims are on par so we will see when I take it for a good rip.

 

Not sure what tuning software your tuner is using, but once your pcm has been flashed.... it doesn't change by itself. sounds like there is more to the story your "tuner" is not telling you

 

He used HP tuners. He took the car back and I picked it up today, no charge, so far no check engine and it runs perfect!
But if anybody has some insight as to why everything mechanically ran perfect and the tune went weird I would like to know from a tuner's point of view what possibly could have happened. He sat right there in front of me in the car while it was idling showing me that it changed somehow from before. But if anybody has some insight as to why everything mechanically ran perfect and the tune did what it did I would like to know from a tuner's point of view what possibly could have happened on his end.

 

When you say he installed the tune and everything ran great prior to your 10 mile drive, did he run a log of the tune?

 

Of course. First he logged the idle speed data then he took it for a 10 mile run. Wide open throttle 3 times in 4th gear and then said everything was perfectly in safe parameters. Even put a wide band on it to make sure it was good.. He then showed me the data before I took the car home. I took it up on the highway gave it a full throttle run up to 6 grand in 5 gears. Continued to drive the car for another 3 miles moderately and then the check engine light came on. Lean in banks 1 and 2

 

As was mentioned prior, the tune can't just change unless reflashed. Something changed with the inputs to the tune whether it be hardware related or sensor related, based on your run. Is it speed density or MAF tuned?

 

maf

 

yeah no.... a tune doesn't "Change" on its own. Sounds like maybe he is just covering his ***.

 

It took 10 miles for the fuel trims to go past 25% +- before it would set a light. It may have been a heavy declaration or any other situation that he/she may not have experienced while tuning. It sounds like it needed a simple adjustment, don't put any more thought into it IMO.