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Any help is greatly appreciated! The problem is that the truck is running strong right after it was tuned.... The problem is that when I put fuel in it, it acts as though it was never tuned for around 5+ minutes of driving time, then it goes back to normal A/F readings in boost, but loses power? And the truck readjusts the fuel tables all on its own? Is there something that needs to be disabled with the flex fuel settings/tables?
I would start by checking the evap system. The physical/electrical system not the tuning parameters.
It's not the evap system, because I took the gas cap off and it doesn't do it.... Only when any amount of fuel is added. I'm thinking it has something to do with the flex fuel system/tables? Maybe the tuner left something enabled that he was supposed to disable?
What do you mean by it "readjusts the fuel tables all on its own" ??
The first time I got it tuned at 8-9psi the truck made 450Hp/500TQ, then when I went back to get it tuned for the meth kit I put on the truck only made 384Hp on the dyno before any tuning and the tuner said the fuel tables were all off. He asked me if I had messed with the tune? I informed him of what the truck was doing everytime I would put fuel in it, and he kinda looked at me like I was crazy! Haha. When I left the shop a few days ago the truck made 480/505 with the meth and everything was good until I put gas in.... And I could tell a significant loss in power. I'm positive it has something to do with the whole flex fuel tables/system that the ecu uses to figure out the timing and fueling? Here's a article I found
http://www.gm-trucks.com/forums/topi...ueling-events/
Then post the tune and log. It's simple enough to disable it or to log what it's doing to figure it out.
I'll be back through Lubbock in a few days, so I'll post up the results then.