93 Diagnostic Circuit - No codes

About 6mths ago my fuel pump went bad. Since I got it replaced she's been running like crap, getting about 15 miles/gallon on the highway :eek: (stock v6). I've been throwing parts at her since she's needed them anyway, but nothing has fixed it... so far she's had: New fuel filter, K&N air filter, PCV, wires, plugs; and today I gave her a new ECM.

The reason i replaced the ECM is the main reason I'm posting...
I CAN'T GET ANY CODES!!!
She has an intermittent Service Engine light (on more than off) i've tried shorting pins 5 & 6 of the ALDI and the cheap 'code scanner' that basically does the same thing. The fan comes on, indicating that it's in diagnostic mode, but the service engine light just stays on. It doesn't even give a code 12.

I've tested the cables between the ECM and the ALDI, they are fine. So I assumed my ECM was bad. Especially since she had been surging badly, from 2000rpm>3000rpm if i hit a bump on the highway.
But I put the new ECM in today and still nothing.
Please HELP! :banghead:

I know I could take her to a shop and get her plugged into a real scanner, but I dont want to have to do that every time something goes bad.

Any ideas? :biggrin:

I think 93 had different computer. You might have to put a paperclip into two of the pins to get the computer to flash the service engine light which is the codes.

GO HERE pls... (http://shbox.com/1/how_tos.html)

goto number 16

That is exactly what I've been doing. The light comes on... and stays on.

you might have a bad ICM, or ignition control module, its a shot in the dark, but my ICM went bad in my 89 IROC and it would run like shit no matter what, and had no trouble codes, turns out thats what it was.

Hrm.. so.. how do I test for a bad ICM?

The problem is not that there are no codes, there could be 20 codes, but the car wont give them to me. It wont even start flashing... at the very least I should be getting a code 12 to tell me that the diagnostic mode is operational, but it's not even doing that much.

I just called 2 chevy service depts. They both said that because I replaced the ECM, it needs reprogramming, even though it came from another 3.4L 1993 Camaro. One of them said that's why I can't retrieve any trouble codes.
Does this sound right to you guys?

OHHHHHH yeah definately, i didnt know you had replaced it with a used unit, that explains it, the dealerships are correct. youll have to take it to them to have it setup proporly.