3.1RS

Can you damage your ecm from jump starting your car with the key in the on position??

Jerriko 3.4

It's possible but not likely. Are kind of problems are you having to make you think your ECM is bad?

3.1RS

Well my o2 sensor is sending a rich running signal yet the fuel trim lowering and trying to make the mixture even richer.... if that makes sense. It runs bad at idle and has a slight misfire at mid rpms. Ive checked everything else and thats all i can think of. Do you have any other ideas?

Jerriko 3.4

Is it throwing any codes? How do you know that you are getting a rich signal from the O2? How do you know that fuel trim is trying to make the mixture rich?

3.1RS

No its not throwing any codes and i know that information because i hooked a GM tech 2 up to the diagnotics port and looked at the data stream.

3.1RS

Anybody??

kretos

i highly doubt your ecm is screwed

Jerriko 3.4

OBD I setups aren't always accurate at diagnosing O2 sensors. The voltage on the scantool isn't update fast enough for you to get a good picture. You need a wideband. Just because the scantool switches back from lean to rich doesn't mean that's what the engine is actually doing. That's just what the computer is trying to do. The easiest way to proceed is to unplug sensor one at a time with the engine running. When the engine runs better, odds are that is the problem area.

3.1RS

do that to all the sensors??

Jerriko 3.4

Yes, but one at a time. I would start with your MAF/MAP and then the TPS.

redraif

Not that is is not possible...I'm on my 3rd. First one was a starting issue. 2nd threw a code and ran like crap. 3rd so far so good. This was all in the course of a year!

Jerriko 3.4

If you had tried using an ecm with a different burn number, it would run odd. The difference between a 7302 for an automatic and a 7302 for a manual for example.

TomP

Only thing I'm aware of that could get damaged is the spark module in the distributor... but that's usually if you leave the key in the "on"/test lights/play radio position with the engine off for a long time. Supposedly the ignition module can overheat.

Did all of this happen today? What I'm getting at is, if your battery ran down to crap, and you jumped it, and the battery's okay now, then maybe you just need to reset the computer and go for a long drive so the ECM can re-learn the car.

It's my experience that the ECM will take a lonnng time to re-learn the car if you drive around down; I gotta take my car up on the highway for it to act right (I drive a half hour away, then a half hour to get back home, and I'm good to go).

Of course, none of that makes sense if you're throwing a computer code.

Gumby

Not quite sure how you mean that??? How else could you jump start it without the key being on???

But since these computer powered cars have came out most manuals and even sticker under the hood say to only hook up the positive to the battery. The negative or ground should be hook to something metal on the engine. It also seams to work better / jump start a car better.