Hello- I have a 1991 Camaro RS that had a 305 TBI. I swapped in a 1991 TBI out of a chevy van. The Camaro has a 746 ecm and the van has a 747. I kept the 350 knock sensor and injectors. I swapped out all the other sensors that plugged into the car.
I got it to start and run with the 305 ecm. It does not run well warmed up and runs rough.
Will the 747 ecm work better if at all? Can I get the "chip" out of the 747 for the 350? Where is and how do I get the "chip" out? I cannot find any info on this.
Thanks

 

You can't swap the PROMs (chips) between the '7747 and the '8746 ECMs. A fast flashing SES and limp is the result.

To see what is what with the chips head up to the PROM, CALPAK, MEMCAL thread.

The L03 305 swap to the Van's L05 350 should run OK on the stock Camaro ECM ('8746). There may be an issue with the engine or one of the sensors you swapped in. Many times vehicles end up in the JY due to a bad sensor.

The '7747 ECM can be plugged in and tried. It won't use the IAT and the AIR may not work quite right, but it is worth a shot.

RBob.

 

I did try the 747, it ran pretty good as far as power wise, but was still a bit rough especially at idle. That was when I had the timing too far advanced. I set the timing and it still runs better than the 746, but won't idle.
Tomorrow I will get out the scantool and dig out the ODB I cable and see what the codes are.
Thanks