First off I have a 2011 Silverado 6.2 with a SD tune. It was stock with a s475 turbo custom tune ran great. I pulled the engine install all forged lower and put Texas speed's PRC 255cc 6 bolt heads. Cam is 230 /231 608/601 115CL. Stock truck intake. And a S480 turbo. Start the engine it idle a little low but idled. Engine idle hunted a little about 2 min and cut off. Now the engine will not idle but run good if you keep it at 1200-1500rpm anything lower engine cut off like you turn off the key. It also cutoff if you put it in gear at 3000rpm. But if you put it in gear and throttle it hard it will go in gear and you can idle it down to 1500rpm and runs good but if you go lower it will cut off. Running at 1200 to 3000 rpm the ECM it pulling fuel -27 fuel trim timing around 32 to 42. When it cut off the timing is going down but hard to see because engine just die. What you guys think. I need help.

 

Sounds like the tune is just way off. Start dialing in the VVE table.

 

I hope that it. My tuner is think a vacuum leak. I sent it once to him. still cut off. What do you think the ecm is doing wrong???

 

The PCM is not doing anything "wrong". It's more than likely way off in the VVE table (like Slowhawk stated) in relation to your new changes/setup. Obviosuly, that's assuming that you don't have any other mechanical issues.....ie: vacuum leak, etc.

And if your tuner is unable to fix it (assuming that you're paying him to fix the issues), then I'd be looking for another tuner.

 

I will check for a vacuum leak, but anything mechanical I missing. engine sound fine runs smooth at 1500rpm and up. ?????

 

I would imagine the trims would go positive if it was a vacuum leak. if its pulling that much fuel at idle/cruise, it just needs to be tuned.

 

Sounds like it is likely just some tuning issues. Hopefully your tuner can straighten you out. If not we are not too far away from you.

 

Thanks you guys. I think Im going to get a vaccum pump on the map sensor and lean it out to see if I can get it to idle. Plus put a little something around the intake to check vacuum leak just for a piece of mind. I to think if its pulling fuel it doesn't have a vaccum leak.

 

Sounds like a good way to half-*** things. Just get the car tuned by a competent tuner, and be done with it. Why would you waste your time doing anything else?? Or, is your tuner just not able to solve it?

 

I'm going to get it tuned. the map idea was just to hear it idle. Thanks guys I will report back.

 

Found out whats wrong its to rich. Leaned it out idles great.