Hi!
so I am having starting issues. When I turn the key, 27.2% of the time it will start; the other times, I get a single click...sometimes if I leave the key turned for an extra second it’s starts. Battery is full, I can jump the purple wire and start the car 100% of the time. Anybody dealt with this before? Where do I need to start the troubleshooting process? Car is a 91 5.7 TPI

 

Here on the lower righthand side of this diagram is your starting circuit. I'd connect a 12V automotive test light to the yellow wire, and see if there is power there when you try to start it and it doesn't. If there isn't it's likely your ignition switch. If there is, I'd then move the light to the tan/white wire, if there isn't power there, it's likely the VATS relay being either defective or not being engaged by the VATS module. If there is power there, the next suspect would be the "Gear selector switch". Note that either the ignition switch or the gear selector switch can be out of adjustment, but if they haven't been moved, and since it'll eventually start if you hold the key long enough, that's usually more of a symptom of a bad contact in either the ignition or gear selector switch, or the VATS relay. You basically need to follow the power through the circuit and see where it's getting lost, it's not even out of the question for it to be a bad connection in a place such as where the purple wire passes through the firewall on it's way to the starter.

The test light, when properly applied, will show you exactly where the fault lies..........

 

I will start working through those steps! Thanks for the reply.

 

There is also one other possibility from past experience.if there is a dead spot on the armature that would present like your problem. Had that happen & eventually got a different starter.

 

Not being a smartazz here, , , and with all due respect to your attempt to help the op........

Given that he said it starts only sometimes with the key, but starts every time he jumps power to the purple (solenoid) wire, a "dead spot" in the armature doesn't fit into the description of the encountered symptom

" I can jump the purple wire and start the car 100% of the time."

 

Ignition switch is probs on the way out