512TR Starter Solenoid

Well, the old girl (94 512TR) would not start today (not even a click from the starter), so, after some electrical diagnostics, it seemed the problem was with the starter itself, more specifically, the solenoid which was terribly fouled. No biggie, I will just replace with the WAI unit mentioned in many past threads, only I could not find WAI part number 66-9146 ANYWHERE. The local parts stores wanted to sell me $65 and $114 equivalents. I finally called WAI itself (800-877-3340) and found a distributor in West Virginia (EMS). I called them (800-697-6070) and one is on the way for the grand sum of $13.56 plus shipping.

I love it when a plan comes together....

 

The WAI web site is temporarily down and they do not sell to individuals, so just call them and they will get you to a parts dealer.

 

Yes, Mel the WAI solenoid arrived and it is a beautiful piece. Unfortunately it has nothing at all in common with the Denso starter/solenoid unit on the 512TR. I suspect it may be a replacement for the Bosch starter solenoid, which is the replacement starter according to my starter guy for a 1994 512TR. The Denso units are no longer available.

I tried the new Denso unit Mr. Willie put together for me. It looked identical, fit nicely in place and started the car easily, but would not disengage the flywheel. The drive unit may be a bit too long, causing the starter teeth to remain in contact with the flywheel. He will look and re-measure tomorrow.

Anybody need a brand new WAI starter solenoid for a 512TR Bosch starter?

 

And I might be keen on that used Bosch starter to have as a spare. Send me a PM and we can discuss.

 

New problem: the reason the old Denso starter burned up and the new one would not disengage is that the solenoid is gettting current when the key is in the #2 (run) position as well as the #3 (start) position. So the starter just keeps running and gets over-revved by the engine swince the solenoid does not disengage (until it all burns up - see photos).

I suspect this is an ignition key problem. When I measure the voltage at the I connector, pin 1 (power from ignition switch to circuit board) and then the F connector pin 1 (power from the circuit board to the solenoid) I get the same 5.7 volts when the key is in the #2 position. This should be zero, I would imagine. I get the same at terminal 50 at the starter solenoid, but there is a twist....
may years ago I had low voltage at the solenoid when the key was turned to the "start" position, so I rigged up a rear relay and had no further issues with starting for over 30,000 miles. Terminal 50 actuates the relay, which then provides a full 12 volts to the starter. No problem. I figured the problem was somewhere in the circuit from the ignition to the starter which had been hacked for an ignition kill. I never tested the voltage in the "run" position.

So, IF the ignition switch is indeed faulty, it will need to be replaced (many $$$$). My other idea is to install an engine start button. If I wire this to interrupt the ground to the rear relay, then theoretically (if I figure this correctly), I could turn the key to the "run" position (bringing power to the relay via terminal 50) and activate the relay/starter circuit only when the button was pushed.
OR would it be better to take the white wire from pin1, connector I and run this to the starter button and then from the starter button to pin 1, connector F and bypass the circuit board altogether?
Any thoughts?
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