I have a 1990 that will not start. Have had issues with intermittent starting problems in the past that are persistant and the car will
not start. Turn the key and nothing. Turn it again or multiple times and the starter will engage but the injectors are disabled from
the VATS system. Let the car sit for the 4 minute timer to run down and try to restart - same situation, except the engine will fire
and run for a couple of revolutions due to fuel that had leaked past the injectors from the last attempt to start the car when they were
disabled by the VATS system. I have key # 14 (9.53k ohms) and have verified that the ignition cylinder contacts are contacting the
resistor on the key shank by unplugging the 2 wire harness at the base of the steering column and checking the resistance
measurement with an meter. Not sure what to do next to diagnose and fix this problem. I thought the problem was going to be
in the ignition cylinder contacts or the key and planned to defeat the system by wiring in a 9.53k ohm resistor to solve the problem.
BUT, now that I know the resistance value is getting to the wiring harness connection at the base of the steering column - the
problem has to be downstream from this point towards the CCM. This is where I need help. I have very little info on the CCM and
how to diagnose this problem any further. Anyone had this problem? Any suggestions?? Need help - thanks in advance for any
help you guys can offer.

 

I recently had to fix this very same problem in my 1990 IROC-Z. Eckler's sells a VATS bypass kit for <$30 that I'm pretty sure will cure your problems. :yesnod:

 

My VATS problem was fixed by the VATS bypass (Eckler's $30). However, mine only did the total no start. I never had any partial start of any kind. Just turned the key and nothing. The drawback in using the bypass is that you have eliminated the anti-theft feature making it easier for your car to be stolen. I am always with my car and practically never leave it in a vulnerable place so the bypass worked for me. Try using a brand new GM key, this worked for about a year.

 

I have looked into the bypass system you are referring to, it will solve the problem if you have an issue with your ignition cylinder
contacts. I have verified mine are good and the system will continue to fail the same way even with the bypass kit installed. The
only thing in the kit is a resistor that is connected to the male pins of the wiring harness that comes from the CCM. I believe my
problem is beyond what the VATS or PASS Key system bypass kits can solve. Looking for someone that may have had this issue
and what it took to solve. I did find a service bulletin from GM (Chevy Dealer Service Bulletin 87-140) on 86-88 Corvettes with
intermittent start problems caused by the VATS system. Have verified the issues identified in this bulletin are not an issue with
my 90 (even though it is 2 years outside of the bulletin). It had some good general info, but did'nt solve my problem....

 

You may also investigate the drivers door lock and be sure that when you unlock the door the key is at the full vertical position. May also require a new door key.