How do I know If my car is entered limp home mode ( or default)?....Its a 89 iroc 5.0 T5 . the past few weeks its been running rich and no power and horrible fuel economy....any ideas?

 

That is a good question. I don't know of a sure-fire way to be able to tell whether it is in limp mode or not.

When in limp mode the SES light will be solid on. But that can also happen with a malfunction.

I do know of 2 signs that the ECM is in limp mode: at key-on, engine-off, the SES will come on, blink off, then come on solid. If the 'blink off' does not happen, then the ECM is in limp mode.

The other sign is if the SES light is flashing rapidly. This is caused by a bad PROM/MEMCAL and the ECM will also be in limp mode.

But if you are driving down the road and the SES comes on solid, it may be limp mode or from a malfunction code.

As for your issue with running rich, the most common issues are: bad MAF, bad injectors, bad FPR.

Disconnect the MAF connector and see if it runs better. Check the FPR vacuum line for fuel. Do this with the fuel pump jumped on and the engine off.

The '89-'92s used Multec injectors which are now failing left & right.

RBob.

 

Thank you very much for the info.... my MAF doesnt throw a code however the SES light does stay on before i start the car. Im suspecting the MAF is bad....

 

Do the paper clip trick to see if there are any codes stored in memory causing the light to come/stay on.