I'm trying to locate the vats module in a 90 corvette.

Check starter relay for proper power and operation. Underneath drivers dash area

It's a ten minute procedure, from what I've read. From Lock to On for 10 minutes. Back to Off, then try to start. May have to do it up to 3 times.

Corvettes had vats since 82. If it matters.

http://vatspasslockpasskeysecurityhelp.yolasite.com/

Sounds like ignition control module (small plastic piece in bottom of distributor). When it gets warm it's shorting out. Easy fix, disconnect battery, pull cap & rotor - gin module is 2 screws in bottom of distributor and 4 wires - replace wires in exact order and coat bottom of middle with dielectric grease, replace rotor, cap & connect battery NEGATIVE CABLE LAST!

It is your vats system it is locking you out. It is not reading the ignition key chip. You can by-pass the system with $5:00 worth of parts from your local radio shack. You must read the resistance across your key chip first then go to radio shack and pick up the resistors needed to match your key chip(they will assist you mine read 1850 i have a 86 vette), twist/tie them together then solder & tape them up with electrical tape. Bend them into a u-shape, locate the the 2 wires that run to your vats logic module that is tied into your ecm, should be in the middle area of your dash next to your radio(yellow and brown in color. Cut those 2 wires and add your (radio shack) resistor series between them and happy motoring no more vats problems for ever. Good Luck

Go to this website and it explains your VATS in detail it sounds like your VATS may have been disabled but as I am not there to see the wiring harness or if wires have been cut I can't say for sure, But go to this website http://vats.likeabigdog.com/ and it goes into great detail with instructions and photos. to answer your issue.

Hope this helps please do not forget to rate/vote or place a testimonial on my advice and if I can help further please do not hesitate to ask as i have a 1984 Camaro Z28 in my yard that we are starting to rebuild and have owned several and performed my own mechanics because I wanted it safe and right. And my husband is a 22 year controls electrician in concept design and engineering so when in doubt I can ask him also.

Wicked Angel

I had a similar problem on my 92 LT1 and it turned out to be the opti-spark was bad not signaling the injectors to pulse, if your bypassing the VAT to turn it over then the injectors should fire as well, on the 92 the crank sensor is built into the opti-spark distributor as well, if it turns out to be the opti-spark spring for the MSD sealed and vacuum vented cap or you'll just be replacing the thing every six months, you can test the opti up were it runs into the coil, I dont remeber the exact proceedor but it is on line,

you can try bypassing it like this turn the key on then take a screwdriver and touch the 2 bolts on the starter try that or try changing the fender mounted starter selonoid

REMOVE THE INFO PANEL IN THE CENTER. THE RELAY IS BEHIND THE INFO PANNEL. YOU CAN HEAR THE RELAYS CLICKING. YOU CAN CUT THE WIRE OF THE RELAY TO STOP THE RELAY FROM ACTIVATING THE IGNITION CUT OFF.
IF NO OIL PRESSURE THE ENGINE WILL STOP, CHECK THE OIL PRESSURE. GO TO CORVETTTE FORUM .. NEED SLEEP !

BUY A REPAIR MANUEL AT AUTO ZONE OR ADVANCED THIS IS A EASY REPAIR YOU CAN DO IT AND SAVE YOUR SELF$250-$1500 DEPENDING ON WHO WORKS ON IT.