My 92 iroc starts fine when its cold. Idles fine, runs good, no spark knock. But it starts like the timing is to high. I checked it out with datamaster and i noticed that the timing a 750 rpm was a 20 degrees. Is this about right? It seems high to me. I set the timing at 6 degrees with a timing light with the proper wire disconnected. I would appreciate any advice. thanks

 

Are you positive that you have a 92 IROC? The made IROC's till 1990.

 

Your right its a z28 I was thinking about an 88 iroc i sold a few months ago.

 

During cranking the timing is at the distributor setting, 6 deg BTDC. Once the engine is running the ECM will take control of the timing. The 20 deg at idle is correct.

If it is cranking slow I'd look into the battery, cables, and stater.

RBob.