[mlipmd]

I tried a few times to post this here but keep getting timed out so I'm just copying what I posted on the C4 ZR-1 section of the Corvette Forum.

For those of you that have followed these threads, here's a new better way to fix this problem.
Twice now I got the DNS, both times parked in a shopping area parking lot. Had to wait 30-45 'min. till the car cooled off then it would start right up like it never happened. PIA as well as embarrassing.
I have been reading a lot about this on this and the ZR-1registry forum and the best advice is to modify my '90 to the later '93-95 ignition system by bypassing the CSS and installing a relay to power the starter solenoid.
All of the relay mods talk of finding the purple wire in the wiring loom and cutting it, using the CSS end of the wire to trigger the relay, and the output goes to the other end of the wire, used to power the starter solenoid.Cutting wires is scary, but there is a much easier,better way without cutting any wires.
If you take down the DS dash panel to gain access to the CSS wiring preparing to bypass it, the first thing you will immediately see is the light yellow with ? blue or black stripe wire (wire looks white, so from now on whatever color it really is, I'm calling it "white" because it looks white to me), alongside a purple wire, in a black connector, connected to 2 black wires leading up higher to the CSS above the clutch pedal.
Don't go looking for the CSS itself, it's buried way up underneath the dash and you don't need it for anything.
If you take apart that connector you have the ends of the white wire from the ignition switch and the purple wire leading out to the starter solenoid. If you just want to bypass the CSS, just connect a short jumper wire to the 2 male terminals in that plug. But if you want to do the starter relay mod, why would you want to dig around in a wire loom and look for the purple wire and cut it for your relay connections? You have the end right there.
Very simply, use the white wire to trigger the relay, use the purple wire for the output to the starter solenoid, all by very simply attaching a short jumper wire to each in the male plug in the connector.
So when my 60-80 amp heavy duty relay arrives tomorrow, I am going to plug in a new 12V hot lead to pin 87, the purple lead connected via a short jumper in the connector plug to 30, the white lead (from the ignition switch) via a short jumper in the connector plug to 86, and a ground from somewhere under the dash, to a bolt handy, to 85. Very simple, no searching for a purple wire to cut, less connections, less resistance in the circuit, and much easier. In addition the whole thing is hidden under the dash, out of the weather, out of the heat, out of sight. Also, if I ever want to restore it back to original, all I have to do is pull off a few jumpers and hook it back up the way it was, no repairing cut wires.
The only thing I have to figure out is how to run the 12V hot lead into the cabin. I can enter via the driver's door accordion, poke a small hole in the bottom and then silicone it up, I can enter via the grommet that the hood latch release cables pass through, also poking a hole then siliconing it up, or I can run a lead down in front of the door hinges protecting the wire inside a 1/4"vinyl tubing and lead it right into the cabin. I already checked and there is plenty of room as the door closes and nothing would get squished but that would be pretty unsightly and not very professional.
Tomorrow if I get to this I'll post some pics but this seems to me very much easier and less destructive and easily reversible if you want.
Hopefully after this I'll never have that DNS happen to me again.