No Start after VATS bypass...

[krazydog]

My '91 ZR1 still starts every now and then even after I installed a Mid America VATS bypass. I would appreciate any suggestions on what to look at next. Thanks!

[krazydog]

No turning over, no clicking, no dimming of lights. It cranks, drives to a restaurant, come back out and it doesn't start. Go back two hours later, fires right up. New battery and alternator. VATS bypass has a resistor that fools the system into thinking the correct current is being applied, I think. Thanks Dynomite!

[krazydog]

sounds possible D, but sometimes it won't start cold either, like this afternoon.....I haven't started it in over a week....the car wouldn't start, installed the bypass and it fired right up, two hours later it fired right up, drove it about 5 miles stopped it, 5 minutes later it wouldn't start, I've owned a lot of cars in my life and never had a problem like this....pretty darned fustrating

[krazydog]

er frustrating

[Kevin]

bypass the clutch switch

[krazydog]

I've owned the car for about 2 years and haven't replaced the starter, so it could be the original.

[scottfab]

Your best approach in my opinion is to temporarily bypass that
clutch switch. Do it so that you can possibly avoid another incident
of no-start.
Here is my thinking.
This is a preemptive move,
if it keeps another incident from happening you found the problem.
If the problem stays intermittent then you know that's not it and your closer to knowing the root cause.

[krazydog]

Thanks guys you've been a lot of help! I'm gonna bypass the clutch switch and hopefully it will solve the problem.

[scottfab]

Originally Posted by Dynomite

After you bypass that switch as part of your diagnosis, and if you find the switch is causing your no start issue, my preference would be to replace the switch with a new clutch switch. That switch is in ALL C4 corvettes as a safety feature and I am used to it for starting just in case it is in gear and fires up instantly as my Z now does.

I would then also install the "No Start" Relay to assure full battery voltage is passed on to the Starter when starting.

Starter Relay, Wiring Harness, and Plugs Tricks

Or you could have a Clutch Switch Linkage issue as I had on my 90' Corvette No Start Clutch Switch Linkage

Cliff makes a good point here on the safety issue.
I'm currently involved in a project on my car installing many discretely mounted switches for emergency use. There'll be a thread on it when I'm done. The idea of "emergency" switches is that they are to be used to get one out of a "no-start" for both, electrical AND fuel related no-starts.

Added later:
Here is the link to the two switches I added:
Two Diagnostic Switches