I’ve been suffering under the woes of an ongoing problem with my 93 coupe, 101K miles. A little in the way of history, the opti died about a year ago. It was still running ok when I tore it down. I put in a new water pump, new opti. Sealed it up good with re RTV. I admit I didn’t drive the car much. Due to some personal problems, I finally let the insurance and tag elapse, but I’d still crank her up a couple of times a week, and warm up. One day it wouldn’t crank. Starter engages, but no ignition. I replaced the ICM, and the coil. I later found out I could test the ICM at O’Rieley’s, and they said it was OK. I’m getting NO CODES. No fire ate the plugs or coil. The ground connection on pin C - BLK/WHT wire is a good ground. I checked for f 12 volts at pin A - PNK /BLK wire and pin D – Dark green wire. This is on when the key switches ON. I don’t see any A/C volts and connect probe to terminal B – white wire, when the engine spins over.
The parts are just too expensive to shotgun another opti, with only suspicions. What about the on board computer. Is it the PCM? I got to thinking about this the other day. If the device that reports the codes in defective, no codes could be an indication unto itself. I have suspected an after market alarm system. I found it. Disconnected power to it. No start. Removed the harness from the device. No start. Finally, I saw the big pink wire is the ignition. It comes on with the key switch, so I have put everything back like it was, at least until I get the ignition to work again. If this were an old points system. I could run 12 volts to the + on the coil, crank her up, and go. Is there an equivalent procedure I can use for testing? I was suspicious of the secondary wire going to the distributor, so I've taken the water pump off. The connection semms to be OK I’ve searched the posts. Found similar experiences. But no definitive solutions.
I’m really at my wits end. I’ve owned lots of cars, but nothing has ever broken down so much. It’s very frustrating to me. It doesn’t run. I can’t drive it. I can’t sell it. It’s a 4000lb paper weight! Useless! And the fun is gone. Please help!!!!

 

You could very well have corrosion in the ignition switch causing it to incorrectly read the resistance on your key. You can find the 2-pin harness under the driver's dash running out of the column base (should be orange wires). Disconnect that and see what resistance you read across them when the key is inserted. You can check with GM to find out what the resistance should be for your key to verify it.

I should add that I went through this not all too long ago.....here's the thread that led to fixing that issue:

http://forums.corvetteforum.com/show....php?t=1584175

 

I cleaned the key with alcohol. It measures 3.7K ohms, Wouldn't you know it's a 13! Now the starter won't engage. I'll charge the battery for a few hours and try again. I hope it will start with a good charge. Thanks for your help.

 

Don't know if it helps, but what is the condition of the wires? My 92 paper weight needs all the wires around the icm changed.

 

Do you mean the plug wires? 8mm taylors about 20K miles ago. The secondary on the ICM all look okay. They are taped up in a bundle that I am reluctant to cut into.
THANKS!