gmpp e67 ecu ls376/480

[chevelle 66]

Hello

can anyone help me understand what is hapend after 5000rpm the ecu dumps a ton of fuel in and i cant understand what it is?is it somthing i should turn of?torque control,traction control or what do you guys think.

http://imageshack.us/f/546/20110813159.jpg/

thanks christoffer Sweden

[ivmotor]

Its probably not the "tuning" adding the fuel. The most common thing I see with a fueling issue like this is having the mass air meter too close to a bend. The air will have a tendency to travel on the outside edge of a bend and if the mass air meter is situated in the wrong place it can pick up additional air. If you can "twist" the meter 90 degrees you might be able to fix it.

[killer67]

This cam was designed for LT1/LT4 in the 90's. Cam sounds great and is good for midrange and gentle on the valvetrain but it idles rough. Wrong lift for that cam. You will have surging issues unless you get a good tune. Cam won't pass a sniffer if you have that.

When engine comes off RPM, duration gives a rich signal and causes ecu to correct , giving the engine less fuel. Stalls out. You will have to play fuel trims, AFR, and throttle position adjustments below 1000-1200 RPM, etc. Not easy to tune at all :(

[chevelle 66]

This cam was designed for LT1/LT4 in the 90's. Cam sounds great and is good for midrange and gentle on the valvetrain but it idles rough. Wrong lift for that cam. You will have surging issues unless you get a good tune. Cam won't pass a sniffer if you have that.

When engine comes off RPM, duration gives a rich signal and causes ecu to correct , giving the engine less fuel. Stalls out. You will have to play fuel trims, AFR, and throttle position adjustments below 1000-1200 RPM, etc. Not easy to tune at all :(

hello

it goes really nice on both idle and midrange but at wide open trottle it goes very rich.

[tooblue]

Is that your Air/Fuel at the bottom of the chart?

If so I wonder if you are going into a Catalytic over temp and pcm is dumping fuel. Not sure who is doing the tuning and may be something you run by them. If I remember correct there is a setting to disable the Cat overtemp.
Roger

[Musclerodz]

Just went through that on the 79 Formula. As Killer said, cam is all wrong in that motor and would never use again or suggest that combo to anyone, make sure your tuner is damn good or he will be fighting this one.

[Bowtieracing]

I have hard ime to believe at GMPP would pick totally wrong cam for their best seller LSx crate motor. Keep the cam and make sure you have maf sensor located as in the installation manual wich came with the controller kit.

[chevelle 66]

Is that your Air/Fuel at the bottom of the chart?

If so I wonder if you are going into a Catalytic over temp and pcm is dumping fuel. Not sure who is doing the tuning and may be something you run by them. If I remember correct there is a setting to disable the Cat overtemp.
Roger

yes it is a/f in lambda,i have got that tip from others too have to test that.thanks

[Musclerodz]

I have hard ime to believe at GMPP would pick totally wrong cam for their best seller LSx crate motor. Keep the cam and make sure you have maf sensor located as in the installation manual wich came with the controller kit.

me too, but do a search on ls3/480 idle problems, and you will find a bunch of threads. Also a bunch of threads on HPtuners about the same problem.