Doghead relay mod sticking too?

[pnishr]

Ok, so a month or two ago I was starting up the 1009, and it wouldn't start. I had recently replaced the starter after running through the troubleshooting in the manual. Since that time, it had started and run just fine several times. So, I didn't have much time that day and decided I'd worry about it another day. Closed the door, locked it up, headed inside, when the starter began cranking on its own. Rushed back out, opened it up, and pulled the OEM starter relay off. I assume this is the relay "sticking" as has been discussed. So, I have since completed the doghead relay modification (I had the dang thing, I know I should have done the mod sooner). Now, it starts ok, but the starter doesn't disengage the first time it is started up. For instance, I go through normal start-up, turn the key, it fires up, but I can hear the starter still going. I shut it off, and the starter is STILL cranking. There's nothing (short of pulling the batttery) to make it stop. It stops on its own after about 10-15seconds. If I try to start it again, it starts up just fine, and I don't have that problem. It's like it's just the first start of the day...? Any thoughts on what is going on? Voltage at the relay is good. I'd call it a short somewhere, but it's consistently just the first start...

This can't be good for my starter or my flywheel. Any help you can offer is appreciated.

 

[doghead]

Did you have damage done when you experienced the starter run-on? Did you inspect and repair anything before simply changing the relay?

Does your starter have tight bolts and the support bracket?

Is your starter shimmed properly? A sticking Bendix drive could keep the starter engaged(powered up).

Have you inspected or rebuilt your starter since the run-on?

Are your wires touching each other(at the starter)?

Have you put a volt meter on the relay wires or solenoid, when it sticks(to determine of voltage is present?

You may simply have a sticking ignition switch (key actuated). Does your key operate smoothly?

 

[pnishr]

Inspected for any fried wiring, found none. Checked all fuses as well.

All bolts and bracket: check.

I need to ensure it is shimmed properly. I will check that.

Not inspected or rebuilt since the run-on. My question would be "how/what would be wrong with it that makes it do what it does?" (which may be answered by the above).

No, the wires aren't touching at the starter. I had that issue when I first installed it, and corrected that after doing a search.

So far I have been too concerned about trying to get the stupid thing to stop, so have not tested voltage at the relay WHILE it has been doing it. I suppose that makes sense...

Key turns as smoothly as it always has.

I'll check that it's properly shimmed, and the voltage during the error. How/why would these only affect the FIRST start of the day?

Thanks for the help! I'm "mechanically" inclined... but electrical stuff is sorcery as far as I'm concerned (even though I CAN read wiring diagrams..)

 

[Recovry4x4]

I had a second run on with mine after doing the mod. Mine ended up being a starter issue.

 

[Keith_J]

You might have damaged the contactor on the starter. Starters are shunt wound so the current increases with speed and since cranking speed is 200-250 RPM, the 650 RPM will allow excess current. This can damage the contactor plate, making it stick.

I cannot see the Trombetta solenoid relay the DH modification uses ever sticking in this application. Now the OTHER possibility is the starter switch itself sticking from the back EMF off the Trombetta relay since it lacks the snubber diode. When this relay opens, the collapsing magnetic field in the coil generates back current which could arc in the ignition switch. Unlikely to do anything but cause ignition switch failure.

The original solenoid relay uses a snubber diode which dumps this back current as heat.

 

[doghead]

My initial guess would be a bad starter solenoid. Possible broken starter nose, or improperly shimmed stater.

I would guess that if you could make it run on again, and you removed either of the bigger wires on the under-dash relay, it would continue to run-on. I suspect your starter solenoid is jambing/hanging up in the "engaged" position, which is also the position that the contact in the solenoid is closed, there-by causing the starter to continue to run.

Possibly after it gets warm, clearances change and allow it to not hang up.

This is all speculation. I would intentionally cause it to run-on and pull a wire at the relay(or the small wire at the starter) and see if it continues to crank. That would prove it is the solenoid, and not the relay.

 

[Barrman]

I had a solenoid stick on me. After pulling it apart I found the contact plate inside the solenoid was bad. It had arced and stuck on. Sounds like you have the same problem. Go with the advice offered in the posts above and move onto the starter being the issue.

 

[dependable]

Make sure your new starter has a 24v solenoid, once bought one that had a 12v one even though it was supposed to be a 24v starter.