Runaway Starter Question

[Robtstee]

Have a 1028. You know the story, all was normal, hit key to start, starter kept going. Proceeded to freak out mode. Luckily had a full toolbox in the bed, ran and pulled both battery cables within 20 seconds of each other. Went to check underdash relay. I had already done the replacement and it works fine. Gen 2 light doesn't come on and I've got some fusible links to replace.I have the Hillbilly gear reduction starter. Figured it was a stuck solenoid, pulled it and no continuity across the poles. Not really familiar with the solenoid operation. 1st question is, why would the solenoid test open dismounted and closed when mounted? I did take it apart and saw nothing out of the ordinary, burns etc.. 2nd question, anything to look for on the starter before I put it back in? Please assume I know absolutely nothing in your replies.

 

[Jeepadict]

If you were inclined to use the search function you'll find a cornucopia of posts that relate to your situation. Personally I can't answer your solenoid question but I would have run my troubleshooting logic tree a little different...never assume a component has failed, trust but verify. First step in troubleshooting is duplicate the discrepancy...2nd step is to cut the problem in half. You have a few components still left to rule out. Give this thread a read:

Runaway Starter M1009!

Well it happened and I need to understand how. I did the DHM over ten years ago and never had a problem. Fortunately, I was able to disconnect the front negative cable in under 30 seconds. It was a cold start and nothing heated up, smoked, or melted down. Truck was bought from the military...

www.steelsoldiers.com

Good luck

Sent from my SM-G970U using Tapatalk

 

[cucvrus]

Nothing is infallible. Make sure the starter is not getting stuck in the ring gear. If it requires a shim use one. But as I always say check the cranking amps of the batteries and make sure the support bracket is in place. the twisting of the starter may cause it to get hung up in the ring gear of the flex plate. Double check everything. Use a competent starter rebuilder to check the starter. there is more to rebuilding electrical components then replacing parts. Good Luck.

 

[Robtstee]

Thanks for the assistance. Looks to me like the starter hung up in the plate, as everything else tests and looks good. Replaced all the burned links I could see, connected the batts without the starter, links started cooking and alt2 let some smoke out. Time for wire tracing, I guess.

 

[Curtisje]

Trace your power from the buss bar to starter. You may have a short to the frame. Happened to me when a pack rat chewed my cable. I also fried some fusible links and watched the smoke escape from an alt. You can't put that smoke back in once it is released. Good luck.

 

[dependable]

Three weeks ago I installed a new gear reduction starter I had sitting new on shelf in one of my CUCV work trucks. It was one of the cheap imports. It got stuck on after working for about a week. Fortunately, one of my employees in the truck had the presence of mind to take off battery terminals before anything melted. It was the solenoid on the new starter that had failed. A good clue was the burnt smell of solenoid and some traces of some brown insulating material of some kind had melted and seeped out of solenoid casing.

The Asian starters are sometimes all that is readily available. Some of mine have worked fine for years, others not so much. Usually it is the solenoid on them that fails, but had one where the gear reduction jammed.

There aren't many sources for new 24V solenoids for MT 28 (gear reduction) starters, all I've found were imported, but I find the Brazilian made solenoids hold up better than the Chinese.

In the case of the truck mentioned above, I put together a decent starter out of a couple of original MT 27's I had around, (one w burnt armature, one w broken nose cone) and ordered a Brazilian solenoid to replace failed one, so I have a starter on the shelf.

 

[Robtstee]

Thanks for the assistance. Looks to me like the starter hung up in the plate, as everything else tests and looks good. Replaced all the burned links I could see, connected the batts without the starter, links started cooking and alt2 let some smoke out. Time for wire tracing, I guess.
[/QUOTE For anyone who found this thread as a result of a search, there was indeed a short, I have no idea why, but when I pulled the burnt capacitor-suppressor I unthinkingly replaced it with a straight wire.

 

[Robtstee]

For anyone who had the same problem, replaced all the fusible links again, disconnected Gen 2, fired right up. Replaced Gen2 went to connect cables and got sparkles on the 24 ground. Traced it to the red wire from the 24v bus to Gen 2 output has 12v on it when disconnected from bus. With every wire disconnected except the wire from Gen 1, all other pins have 12v on them including the exciter, so now to figure that out.