I've found only a few postings on the net about intermittent starting problems for a C5. Description: I place the key in the ignition, foot on the clutch, other foot on the brake, radio off, AC/Fan off, turn the key and nothing happens except for the gauges registering to the right. Everything appears completely normal except the car won't start. Battery is good. In fact, the battery is new. I receive no messages on my DIC. This is happening about 50% of the time or more. (It's a lot of fun when I have a date in the car too.) How do I get it started you may ask... It will always push start but can't always do that, however that at least rules out the pass-key system, right? Otherwise the security would not permit push starting. Well when this intermittent starting happens, I turn the key multiple times, sit there, take the key out, wait a mintue, swear..etc.. and it randomly starts up when I least expect it. It's even starting up when the key has been slowly turned back 1/32" to the left. It's started when I've pumped the clutch...It's started when I've just sat there doing nothing but have the key to the right. It's completely random. Vibration or stillness doesn't seem to matter.

I've done as much as possible that I know of. Here goes.
I've tested the starter. (I talked to a starter mechanic to understand how they work and he indicated that the contacts could be remaining in an open position therefor preventing any turning or sounds whatsoever....so I had it tested.)
I've tested and essentially dismantled (twice) the Clutch Pedal Switch found under the clutch pedal arm.
I've had the ignition cylinder replaced.
I've had the keys tested at the GM dealer and apparently they're "tight.".
I've had an "interrupt relay" replaced. (I'm not sure if this is the same as the starter relay.
I've had the steering column lock replaced. I've even temporarily installed a CLB for lack of any other ideas!
I've pulled the fuse box in the passenger side and checked every single fuse.
I've put a brand new battery in it and checked the cables.

Description of what happens:

Put the key in the ignition. Turn it to the right. All the gauges register, fuel pump is heard (if the window is down), then nothing. I do here the relay click if I pump the clutch pedal. The switch at the clutch pedal triggers the relay on the passenger side so I can tell that's connecting. I don't get any messages on the DIC. I don't get any turning or any other sounds. It doesn't seem to matter if the air is on or off, radio on or off. I turn them all off anyway. I'll sit there and play with the key. Back and forth, in and out and even just take it out and wait a minute or two. It usually starts at some random moment. Keep in mind this has happened now for the past two years and only recently appeared to be worse. It has happened to the extent where I've not been able to start it so I've actually been in a few situations where I've had to have it push started. That's another reason I don't think it's related to the Pass-Key system and anti-theft mechanisms because then the car wouldn't be allowed to start. I'm at a loss. I've had it in to a mechanic that works only on corvettes three or four times and it's started every single time for him. Go figure. Any help whatsover is greatly appreciated.

 

sounds like you did the right things to diagnose the problem but it sounds like the starter solenoid is bad or worn, when you have an electrical contact keep hitting the solenoid in the same place on the wheel you get burnt spots and it cant make a contact anymore in that spot, try hooking up a hot-wire to the starter and see if you can manually push button the starter to turn, if the key dosent start it and your push button does, then the problem is within the electrical system, possibly computer?, but if the pushbutton hotwire dosent start it then you just need to get a new starter solenoid..... I've had this happen to many of my gm vehicles in the past...

 

Thanks for the reply. I just got it actually. I don't think it's related to the starter only because I had a meter on the solenoid when I turned the key during one of those time when nothing happened and there was no power to the solenoid. That would suggest the problem is "up the river" somewhere. Any other ideas? You can write me at mjwright@wilsonco.com or in this thread. Thanks! Any help is appreciated. I'm almost to the point to offer a finder's fee for getting the problem solved.

Thanks again.
Michael