I just bought a 1993 z28 6 speed for my son. After doing some research I found one with an MSD vented opti, new plug wires and a new coil. The car only has 120,000 miles and was running fine. I died yesterday and now has no spark. I tested the fuel system and it's fine. Tested all the ignition and it pointed to the ICM. I replaced it but still no spark. Is there anyway to test the ICM? ($100 at Autozone could it be bad as well?) It coded 46 and 63, but the Vats is fine (only stops the motor from turning over) and I didn't think 93's had heated O2 sensors. Please help.

 

check your fuses in the inside fuse box. also check to see if your 02 sensor wire is grounded to the exhaust.

 

If there is no spark it is not due to the VATS as the VATS only shuts down the fuel injectors and prevents operation of the start relay.

 

Thanks for the response, here's where I'm now;

Ok, so the fuse is good does a 93 have a Pass Key II? If so how do I check for an open CKT 229 circut? The O2 wire looks good. I unbolted the ECM from the fender to see if the wires were cracked or broken. The ECM looks like the cover is off! It looks as if the ECM is supposed to be incased in a box but bolts are missing and the top is gone. Someone at sometime has messed with this. Could this be it or am I worried about nothing?

 

nah it just looks that way. i have mine covered with a big glad freezer baggy. yes you have a passkey 2, the pictures are from my 93 factory service manual. curcut 229 is a dark blue wire going to the decoder module. need to see if it ohms out as being grounded. ive got to go, gota couple games to coach and have to get ready. ill be back later if no one responds. in the mean time check for power to the pink wire to your coil when the ignition is on. do a little research on here.

 

I know you need to go but where is the decoder module?

 

A bad O2 sensor or a open or grounded O2 sensor lead will not prevent the engine from starting. The ECM does not use the O2 sensor until the engine has warmed up.

Most parts stores will test the ICM module for free.

The Theft Deterrent Module/Decoder Module is way up under the dash on the passenger side. There are 3 modules in this area, the one you are looking for is the middle one.

 

Looks like I have some work to do. I'll let you know what happens. Thanks.

 

I must be in the wrong place. AllI see is the air bag sensor, heater fan and one big silver box? Am I too far to the right of the car?

 

its to the left of the glove box under the dash