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[Vettefan87]

The car will not run unless the throttle is constantly stabbed. I originally thought it was an ignition component,(plug wire possibly), however after a complete tune up no change. Craig has been burning me tunes and we looked to that next. We threw an old hypertech mem-cal in, and no change. I put the moates adapter back in with the flash chip, and accidentally put the mem-cal in backwards.The car runs fine, however it throws a code 41, (faulty or incorrect mem-cal).

So any ideas as to the problem?? Oh we did put another stock mem-cal in and the car runs terrible as well. Is the ECM bad? I remember reading something about limp home mode, is this why the car runs fine with the mem-cal in backwards?

 

[Vettefan87]

Just as an update I threw my ECM off mine into Craig's car and his ran fine. So I would imagine the ECM is good.

 

[rrubel]

Two thoughts - bad vacuum leak, or loose wire to an injector (possibly from the ECM). I had similar problems a couple years ago and it turned out to be a loose connection on the harness at the ECM for the wiring that controlled the injectors.
[RICHR]

 

[vetteboy86]

I think I would rule out vacuum leak. Loose connections to the ECM seem to be a logical idea, however, would that be possible since the car runs normal with the prom in backwards??

I am thinking that with the PROM in backwards, the ECM is in what I think is called "Limp Mode" in which it only runs on pre-determined tables, ignoring engine data from sensors. What I dont understand is how that is different from open loop operation. I am sure they are different but how.

 

[rrubel]

I put my Prominator in backwards once, and also one pin-pair offset, and both times the car ran fine but threw codes. I honestly can't say what data the ECM is getting at that point...

Do you have an ALDL monitor to see what's going on?

[RICHR]

 

[vetteboy86]

I was running Datamaster, and everything seemed to be reading back to me. However I did notice that the O2 wasn't cycling, and in closed loop. Now that I think about it I am not sure it ever went into closed loop. I will have to look back at that scan.

The car runs like crap and doesn't throw any codes, but put the PROM in wrong and it runs fine?

 

[G Winter]

I have never tried this but does it run without the prom ?
If not is it possible to have the chip in backwards when it was programed ?
a couple yrs ago I had an issue with the car running fine when cold but when warmed up ran like crap.Turned out I had two weak injectors, low ohms on the coils. I figure when cold it was dumping in lots of fuel with the rest of the injectors and made up for the two bad injectors. I replaced the two bad ones and it ran fine.I would also look at the TPS it might not be sending the correct voltage to the ECM thus if it is lean then stabbing the throttle might cause it to give more fuel.

Glenn

 

[vetteboy86]

The car runs bad regardless of temp. It's odd because everything was fine, and then in the morning when he tried to start it this problem occurred. My problem with trying to blame it on hardware is the fact that when the PROM was put in incorrectly.