So a few weeks ago my 1991 formula 5.0 5-spd all of a sudden gave me some starting issues. I have done a little reading and tried to apply some common sense to solve the problem, but so far I have not had any luck.

One Saturday, I put the key in the ignition, and tried to turn the key to the "run" position, but I could not get it to rotate. I tried turning the key forward and backward, but could not get the key to turn. Finally after many tries, the key did rotate forward and the car started (and seemed to actually extend past the normal start position). Immediately after I got the car started, I then tried to turn the key to the off position, but the key did not want to turn back into the off position (it was stuck in the forward position). Once again, I kept applying a twisting action (back and forth) to the key, and eventually the key did turn back and the car shut-off. When I tried to start the car again, I had the same problem with trying to turn the key. I could not get the car started.

My initial thought was a bad lock cylinder, so I replaced the lock cylinder. While I had the steering wheel off, I also replaced the ignition switch.
I went to my local GM dealer to get a new key made with a resistor pellet/chip that matched my old key. I tried the new key in the lock cylinder, and turned the assembly to the run position. The "security" light popped up on the dash. I waited over 10 minutes, and the light never went off. My next thought was that the new key had the wrong resistance. I used a voltmeter to measure the resistance of each of my three keys (1 original, 1 original spare, and the new one). The resistance values were slightly different. So, I tried each key in my ignition. The only one that caused the "Security" light to turn-off was the original. Even with the light off, the car would still not start. I am out of ideas right now, so if any of you have experienced this problem, please shed some light. Your help is much appreciated.

 

may be a bad starter relay. when you turn the key, do things act like you're trying to start the car ? temp gauge pegging, hvac blower motor stopping ?
may also be a bad clutch safety swith

 

Deadbird, I appreciate the response.

Yes, when I try to start it, the temp gauge was pegging (the temperature gauge needle moved from 100 to 260) when I turn the key all the way forward. Then the needle goes back below 100 when I "let off" the key.

I looked up starter enable relay and found a picture on thirdgen of what I think it is. Is the picture on BigMyke's post (9-20-2011) correct?

https://www.thirdgen.org/forums/elec...le-vats-3.html

On my car, the plug/connection that is circled in BigMyke's post picture is just hanging below the fuse box. I have looked around to see if I could find what or where it connects to, but I do not see anything. Do you have a picture of what this connects to? Or where do I need to look?

 

the relay was bypassed in mykes picture, the relay plug is circled and just NorthE of the circle, you can see the starter (yel) and relay (grn) tied with a barrel connector.

 

To add, that connector plugs into a relay. Iirc, the vats relay was behind the kick panel (where the hood release is), though, don't quote me on that.