Start (inhibit) Relay weirdness

[TTait]

10684

I've got a little weirdness here. Seems I don't understand something pretty basic.

My starter has been intermittent, turns out its not the starter. The problem appears to be in the starter relay.

I get good voltage into the relay base when the key is turned from red/white, I have a good ground at the relay base via yellow white, and I hear the relay clicking. I have good voltage coming in from brown, but I do not get any voltage passing through to red/white when the coil pulls closed (when measured at both the bulkhead connector and the connector wire to the starter itself). I have swapped around relays and can confirm all relays are operating properly.

When I insert a jumper into the relay base from red/white to red/white, it starts every time.

It would appear that I am not getting enough juice to completely close the relay? Can the voltage I see from the brown wire drop to zero when the coil closes? I don't know - I'm confused here.

I'd like it to be right, but I'm also curious... Do I even need the relay in a 5 speed? At first glance it is only there to stop an auto from starting when the car is in gear. Does the starter solenoid draw enough power that I really want the relay, or would I be better off with the jumper, and eliminate the possible point of failure of the relay?

All in all I'd like to understand the underlying issue, and fix it, regardless of whether or not the relay even serves any benefit.

Help?

Tom

[Bitsyncmaster]

The starter solenoid draws a lot off current (> 10 amps). The original wiring did not use the relay but I recommend you keep it unless you want to replace the starter switch someday.

How do you know you have a good ground? I've found bad relay grounds. Measure the ground with an ohmmeter to the group of grounds in back side of relay compartment.

[Ron]

You aren't displaying your VIN...if you have a an early VIN, you should do a search for the starter mod service bulletin.

It sounds like the brown wire may not be supplying enough power. It may read 12V, or more, but not be able to handle the load!
Try using a jumper to bring 12V straight off of a known good source to the relay (brown wire), ideally the battery (+), and try it (relay installed).

Bypassing the relay (jumping the RW to RW) is not a good idea. It is unsafe for autos/manuals and the ignition switch is not designed to handle the load required to energize the solenoid.

[TTait]

Two cars, this one is 10902, so it should be all set with the starter mod. I did replace the main engine wiring harness, but as I understand the mod that is irrelevant.

I'll build some jumpers so I can set up a perfect ground and power supply, bypassing the brown and yellow wires, and come out of the red white to the coil and power in to the red white running to the starter.

I'll also check the resistance through the yellow and brown to ground and batt+.

Thanks guys. I'll post again with results.

Tom
10902
03238

[TTait]

Its an weak ground at the relay socket. I'm running for now with jumpers extending the relay up out of the socket, and the bad ground temporarily bypassed. I'll get under the relay bases probably this weekend and fix it from the underside.

Thanks guys.