Starter Problem

How would you install that?

 

I don't think the solenoid is engaging.

I'm assuming the "control wire" is the solenoid engagement wire from the ignition switch and not the battery cable attached to the starter motor.

 

I used the Ford relay to power the starter.
Solenoid wire (purple) to the S terminal of the solenoid.
Battery cable to solenoid.
Battery cable from solenoid to starter.
Jump lead from starter motor to starter relay.

I mimicked the system Ford used.

In line with the solenoid wire:
Ignition (purple) wire to 86
ground 87
larger wire from battery to 30
wire from starter solenoid to 87

The relay in this configuration would provide added power to the stock solenoid. Probably a better (at least simpler) way to do it than what I did.

 

Yeah, twin2's picture shows the Ford solenoid powering the GM solenoid - no battery cable to the Ford solenoid.

It's instructive to take these solenoids apart. They both have a metal disk that drives into a pair of big contacts when the solenoid is energized. You can sometimes repair them by taking apart, flipping the disk, and burnishing the contacts. Usually they die by arcing at the disk, and that preventing good contact.

I kinda think the GM solenoids get weak with age. You'd think that copper windings have no moving parts, and would not wear out, but stuff like this does get weaker with age. More current to the GM solenoid should strengthen a weak part, as long as the windings aren't totally open.

 

I have done the Ford solenoid trick for years. Some Delco starter/solenoids suffer from heat soak and won't pull the solenoid completely when hot. This always solves the problem.