Okay, so my brother is having problems with his car. It literally will not run unless you stab the pedal like a nut. Even when you do get it to run at a little higher RPM (2500) It misses badly.

We just did a complete tune up, and I rule out the possibility of a bad wire due to the next test I performed. In the troubleshooting process, I considered that the prom or the flash IC that I burned for him went bad. I replaced it with just the stocker, and it runs the same. So I put the moates adapter back in, but put the prom in backwards(accidentally) and the car runs and idles fine. It does throw a code 41 (invalid or defective mem-cal).

So my question is this, what am I missing in that when the prom is in backwards the car runs fine, but when in correct it runs terrible. I thought the O2 sensor, but when cold and in open loop it doesn't look at the O2, and this problem occurs in both open and clsd loop.

Any and all suggestions are extremely appreciated!
Craig

BTW, I am searching the boards frantically for clues to this problem!

 

When in backwards you are running on the "limp mode" settings (all hardware, no ECM control)
Sounds like the tuning settings you have burned are worse than the limp settings. Go back over it starting from a stock bin and make changes.
You may have inadvertently changed something to a really bad value.
(Injectors to 300 lbs/hr or something like that)

 

Originally that is what I thought, but the problem started while the new tune was in the car. In other words, he ran on that tune for a good two weeks. We also put just the stock PROM in the car without the adapter, and my tune.

I think you gave me the information i was looking for in that when in backwards the car uses all hardware. Not sure how to interpret that exactly. Does it run just on tables in the ECM, without reading engine sensors and interpreting them.

How is this different when in open loop operation? I am going to do a search on open loop, and see exactly what the ECM interprets during that run mode. My thinking is that it is a sensor somewhere, and when the prom was in backwards, it disregarded that bad sensor. Funny thing is though it didn't set and SES light.

I am going to burn him a stock bin, and see what exactly happens. Would be great if that fixed it.

Thanks for the input!
Craig

 

Can someone please explain to me why the car would run if the Prom was put on the maotes adapter backwards? From everything I read, I am leaning towards the fact that the PROM is put on the maotes adpater in the event of an ECM failure in which this PROM contains the values for "limp home mode" So would the car run without a PROM on the adapter? My original assumption for the car being in "limp mode" with the PROM in backwards must have been false since, the SES light should flicker, not to mention the physical connections to the device wouldn't exist.

So what exactly am I beating around the bush about? I've never experienced this problem, and not sure how to approach it. Whatever happened when I attached the PROM backwards to the moates adapter changed how the car runs!

I could go around unplugging sensors, but that wouldn't solve anything I don't believe as the computer would just throw a code and use a default value. The car doesn't throw any codes by the way.

 

Yea I guess I replied too quickly on that.
The Memcal in backwards would not have the "Limp" resistors in the right place to use the hardware setting.
Something really strange there.
Check the resistance of the injectors and solenoids, one going real bad (low resistance) could cause strange power problems for the ECM.
When you say backwards you mean the OEM chip is lined up with the traces on the adapter?
The correct way is with the OEM chip not connected to the traces. Just checking.

 

I think that is a correct statement. I will double check that when I am at the car.

He was able to start the car with just the moates adapter and the flash IC. He removed the OEM chip from the maotes adapter and the car runs, a little rich, but runs differently then when the OEM chip is connected to the adapter.