EEC Tuner cut-out/CHECK ENGINE LIGHT

Kevin Keenan

Registered User
Hi,

Was wondering if any of you have seen this?

Occasionally, I will be dring my SC around, and the car will start running rough. A few miles, sometimes more after the CHECK ENGINE LIGHT WILL come on and start acting REALLY funny, misfires, stutters, and eventually will stall. Trying to restart the engine results in cranking but no start. Engine just keeps turning over.

If I take my EEC Tuner out the car is fine back with the stock computer and starts right up and drives. Obviously I can't drive this way with the 4.2 I'm using so I have to gently limp it home until I reprogram my Tuner and then the car is good to go again sometimes for 50 miles, sometimes for 5000 miles.

It's like the Tuner is losing its memory or the stock computer is trying to overtake the Tuner. Do you think it may be a problem with the factory computer? With the tuner chip itself. I even replaced the 30 pin AMP connector pins with brand new amp pins and still no luck. It's repeatable again and again, but since it happens at different intervals I'm not sure where the problem lies. And it doesn't happen under specific condittions. Sometimes it happens under WOT, sometimes partial throttle, and Sometimes it happens under cruise.

Just curious if anyone had any suggestions.

Thanks for any input.
 
First thing would be to get the codes pulled and see what they are. I have heared of other people that had tuners that seemed to forget there tune and would have to re-load the tune. If your can live without your car for awhile send the tuner back to Shiftmaster and have them check it out. I sent mine in and they were very quick at replacing it, mine didnt work when i received it.
 
I have had my tuner for over 3 years and in that time it has done weird things occasionally. One day it started doing just like you said but then on restart it was fine and has worked fine ever since.

Then today I installed the same tuner in a different vehicle and it would not remember it's tune for more than one key cycle. Every time you shut the car off you'd have to redownload the file. Then it would work fine, but you would have to reload it each time you started the car.

I talked with shiftmaster about mine and they said that my problem was not something that they could fix. I know that one of the chips gets awful hot if the car runs for extended periods at high rpm. It has turned the chip brown at one point. Someone once said that they removed the tuner from inside the EEC case for better cooling, but that doesn't sound like your problem either.
 
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