I have been having a problem with starting the vette for a fiew months. The first thing that happened was the fuel pump relay would not send power to the fuel pump. So I replaced it, this helped but did not fix the problem. If the pump won't run, when I power the relay, it will. But recently when I turn the key to start, I get nothing from the starter. Everything else is normal, but the starter dous nothing. And these problems are most of the time, some days it will start right up. Can anyone help me.

 

Sounds like a problem with VATS. Do you have another key with pellet thet you can try. Your going to have to test and trace the starting circuit to see where the signal to start is lost. Heres some reading from my manual.
http://members.shaw.ca/agent86/Vats%20Electrical.pdf
http://members.shaw.ca/agent86/Start...g%20System.pdf

 

I had same problem with the starter your having. Some days it wouldn't turn over at all, or click then start or no problem for weeks. Spent lots of time on electrical testing, relay and much more. Was hard to troubleshoot because by the time I started testing, it corrected itself. Really knew it was the starter but did't want to change it for no reason. Finally I decided just to change the starter which cleared all the problems. I assume you have checked battery and connections and all that stuff.

As for your fuel pump, are you fixed on that?

 

Always include your year vette in your post! Try this diagnosis next time it won't crank.
VATS measures the resistance of the pellet in your ign key and if it exceeds 5% from the stored value, it won't allow a crank nor the injectors to be pulsed to prevent push starting. If the value is not correct, you have to wait 6 minutes to try again. When it won't crank, jump the clutch safety switch (gear selector switch if automatic). Connect a voltmeter from clutch switch jumper to ground and see if there is 12v when you attempt a crank. If there is and no cranking, the starter solenoid on the starter is suspect. If no 12v, VATS is suspect. Next try your spare ign key as its pellet contacts aren't worn like your everyday key. Continued problems require a test of the contacts in the ignition tumbler. Remove the hush panel above the drivers feet and locate the two wires from behind the steering column (white on my 87) that go to a 2 pin connector. With the ign key inserted, unplug the connectors and measure the resistance across the wires from the steering column. They should measure the same resistance as the pellet. If over 13k ohms, you need a new ignition tumbler which has new contacts that make connection to the pellet. You can temporarily bypass VATS by connecting a fixed resistor the same value as your pellet across the 2 pin connector going into the wiring harness (goes to VATS module). You can use a 1/4 watt 5% resistor from Radio Shack. Dont' permanently bypass VATS because 99% of thefts are done by bashing the column and jumping the ignition.