My 1990 Firebird occasionally won't start. It has the 350 tunned port motor. When I turn the key, the lights come on, but the engine won't crank. If I wait an hour, when I come back the engine will crank and start right up. This is a rare occurance, it only happens about once a month. What can I do to trouble shoot this, or is it for sure the starter and should I just replace it?

 

Any help here would be very greatful as i have the same problem with my 89 5,7 tpi iroc/z28. It sometimes will hessitae and not want to start at all. I then hook it up on jumpers to another car and imeditly it will fire up, i know its not my batery or alt. not working as i have had to replace both do to other casues recently.

 

I had a similar problem with my 1991 305TPI M5. It ended up being my starter.
Do you hear any clicking from the starter solenoid when attempting to start the car? If you do, you can test the starter motor by bypassing the solenoid.

If you don't hear the clicking from the solenoid, check to see if you are getting electricity to the solenoid when you are attempting to start the car. If you are not getting power to the solenoid it could be the security system.

 

I know that when it happens to me(and thakfully not in the last 2 weeks) that it doesnt make a clicking noice just wont turn over then as i said before as soon as i hook up the jumpers starts right up np.

 

What does your voltmeter in the dash read when you first turn the key to the on position, and also when you are trying to crank?

 

Yes i was cranking it as in to start it, as far as the volt meter reads it reads between the 8 and 13 mark but it will still start when down to 8 as ive done that before. As far as when im cranking id have to check but i know that my starter is pulling about 30 amps when starting as i tried getting help from my father in-law.

 

It is kind of strange that your car fires up when you try to jump start it, but the voltage seems normal. Double check your electrical connection from the battery to the starter solenoid. No clicking could indicate flat spots on the starter solenoid. When the car does not want to start, do you get any voltage reading at the wires leading to the solenoid? You need an assistant to help you with that. They need to be turning the key while you are measuring the voltage at the solenoid with a voltmeter. This will rule out that your problem is not caused by the car's security system (the resistor on the key). Most likely it is your solenoid. When they first start to go bad that's what they do. Sometimes they work, and sometimes they don't, until eventually they fail completely. The solenoid is attacked to the starter, so in order for you to replace it, the starter has to come out. I replaced the whole thing on my car as a unit, and no more problems.