Ok, I've had a knock for a while and I've been trying to figure out why. I finally decided I would take the computer chip from an '86 T/A with the same motor I have in my '87 IROC-Z (LG4) and see if that fixed my problem. Well I don't seem to have the knock anymore but now I have 2 error codes:

1) Error code #41:
- EST circuit failure - no distributer pulses
- Cam Shaft Position Sensor Failure
- Cylinder Select Error

2) Error code #15:
- Coolent Sensor - low temperature fualt

I think I know why I'm getting #15 because one of the previous owners of the car rig the coolent temp fan to run all the time and I don't know how to undo this.

I don't have a clue as to what I should do for #41 and that is where I would like the most help though if you can tell me how to fix the fan problem that would be good too. But like I said I have no idea where to begin with #41. Thanks in advance.

 

If you go back to your original EPROM, do you get the same results?

 

Nope, it comes up clean.

 

My guess is that the two CALPAKs aren't compatible. What is the revision number of each EPROM (visible through the round windows in the CALPAK covers)? There should be a number like "AUM 1893" or some string of characters on a foil label.