Runaway Starter, but different with what wires not to pull

[Dave Kay]

No, no pictures. I have access to a retired gentleman that has worked on electrical stuff all his life. His "retirement" is to use hi one car garage. He is not fast, pays attention to detail and puts in the best parts he can find. I have pulled many starters apart and gotten them to work again. I don't do it everyday or have the desire to put a micrometer to every single part and check it against specifications I haven't looked up. This guy will do that.

When my starter went from what I thought was good starting speed and turned out to be slow spinning to not fast enough to start the engine but melt a battery post off. I took it to him last September. He told me nothing but the shaft and outter case were still good. He replaced everything. I put the starter on and it spun the engine faster than I knew it could be turned. The starter continued to do that for the past 12 months.

When it stuck on a few weeks ago, the starter ran without turning the engine for at least 1-3 minutes if not more until I could get a battery lead off. As stated in my first post of this thread. I was convinced the solenoid was bad because the starter turned but the Bendix wasn't out. However, when I pulled the starter and tested it. All was working right.

I tested the truck side wiring and all was good. I put in another starter, everything worked great and I took the failed that one time starter to my guy. He took a week and called to tell me all was ready. I asked what he found. Bad bushings on the starter shaft and really worn brushes. That was caused by spinning for a few minutes straight. I asked if he found any clue as to why it ran on. He said the plate in the solenoid was "severly arced up." I asked if it could have been the cause of it running on. He said it most definetly was the cause.

That was good enough for me to feel better about driving the truck again. The guy is 30 miles away from me. I am the Auto Tech teacher at my school. The welding teacher here lives next door to the guy and has been my parts hauler. He was supposed to pick up the starter last night but got busy with family stuff. Hopefully, he will get it this weekend. I asked him to also bring back the bad solenoid so I can look at it. We will see if he gets it or not. If he does, I will take it apart and get pictures.

Thanks for that explanation Barrman, I think the bad solenoid theory is just one of those 'truths' that seem to be forgotten/over-looked/ignored while we look all over the place for more complicated answers until the simple solution finally smack us up-side the head--- again!

Few years back a like-new starter did similar things to me and I was pulling hair from head trying to solve problem when some old sage on another forum advised... "first thing--- just replace the solenoid and then see what's what..."

Sure enough solved my problem--- permanently.

 

[MarkH]

Hey everybody,
I have been a member for a while now and have found this site a necessity for any CUCV owner, but this is my first post. I did some searching, and couldn't really find the exact same scenario. I figured It would fit well here because there are many post on the subject, and im pretty sure it was not the common relay failure.

Here is what happened.

My m1009 was my daily driver, and had been sitting for about a week. When I tried to start it it took a few extra cranks normally due to a small fuel leak I have yet to find. Normally it starts first crank, but like I said it had been sitting and required a bit of extra cranking. On the third attempt about 5 seconds into cranking I turned the ignition off, and it keep cranking about 3-4 seconds and the cranking slowed. I saw the voltage drop to about 14V and fluctuate. it stopped cranking, all lights and gauges went out, instant smoke. opened the hood and fire on the block where the 12v wires connect to the glow-plugs and "stuff" (the block to the left of the steering column high on the fire wall.). Immediately disconnected the batteries(both) and they were making boiling noises(gell-cells). not good.

Damage assessment.

I had done the "doghead relay mod". checked the relay, and it is still good. no visible heat/fire damage. checked conductivity and everything is normal.
-starter relay ok

checked conductivity between the first battery connection an ground. found that the system (24v side) is grounded somewhere. pulled the starter power supply off the firewall and the starter was the short. the rest of the system was not grounded out.
-starter grounded out.

removed the starter, and noticed the stud(stud facing the front of the vehicle) was loose. checked the starter on the ground, and could not find a short in the starter on the bench. the power supply (big red wire) to the starter was no longer grounded
-forward facing stud loose.
-starter wasn't grounded after removal.
-starter cable wasn't grounded after removal, but was before.

after inspecting the burnt wires where I saw the fire. there were only two burnt wires. the one the is the main power supply to the block from the first battery. the second wire was the wire coming from the alternator on the drivers side.
-see attached photo.

I will be dropping the starter off to be rebuilt at a good shop on Monday, but I am not totally sure what happened. My guess is the starter grounded out somehow, but I am not sure why the alternator wire burnt out.

Any input would be greatly appreciated.

 

[MarkH]

 

[cucvrus]

If the starter gear got stuck out in the ring gear it would not be able to release itself and it would stay engaged in the ring gear. As long as that gear is out there the starter solenoid is engaged the starter will still stay cranking as long as voltage is present. I think I said that right. Probably not. But that is my thought on the subject site unseen.

 

[doghead]

Does your starter have the support bracket?

Are your starter bolts tight?

Have you ever heard any odd sound when cranking it over?

 

[MarkH]

Does your starter have the support bracket?

Are your starter bolts tight?

Have you ever heard any odd sound when cranking it over?

1: have the support bracket.

2: the support bracket nut was loose when I removed the starter. other two bolts were tight.

3: every now and then it will do the grind noise when the ring gear stops in a spot it is missing teeth.
- side note: I replaced the ring gear about two years ago, it seems soon for it to loose a few teeth, but it has.

 

[MarkH]

If the starter gear got stuck out in the ring gear it would not be able to release itself and it would stay engaged in the ring gear. As long as that gear is out there the starter solenoid is engaged the starter will still stay cranking as long as voltage is present. I think I said that right. Probably not. But that is my thought on the subject site unseen.

so if the starter gets caught in the ring gear it will keep supplying power to the starter until it retracts?

 

[doghead]

Yes

 

[MarkH]

That is most likely what did it then.

Why did the wire to the alternator burn out?

 

[doghead]

That is a question that I think Warthog can answer better than I.

 

[roveroverme]

That reminds me of my starter Issues.
On my starter the bolt that is holding the fork for the bendix drive in place was almost all the way backed out causing the starter to not properly energize .

 

[cucvrus]

That is most likely what did it then.

Why did the wire to the alternator burn out?

I think it is because of low voltage/amperage going to the starter and it creates the heat and overloaded the fusible link. That will happen anytime the starter is engaged for an extended period of time and the voltage / amperage drops creating heat. My opinion. It looks like an easy fix. It sounds like you need to change the ring gear/flywheel/flexplate and have a qualified starter repair shop go over you starter. Also have them look over the starter drive engagement. The starter may need a shim or more between the mounting base and the engine block so that it is properly engaging the gears/teeth of the flexplate and starter drive gear. You may be going into the gears to tight and that is what is keeping it stuck out there. I have seen very few that needed a shim but I have seen them. I had a guy eating flywheels every year
or so and that is al it took was 1 thin shim to eliminate the flywheel being eaten alive. GM had several service bulletins out on this issue. Some one here may have them. I know I do but I can't post them. Good Luck I hope I helped you out. Have a good day.

 

[MarkH]

I really appreciate the feed back. I will be dropping off the starter today and will tell them about it eating the ring gear. It looks like I made it out of this one pretty easily with only two burnt wires, but we will see when I reinstall the starter. Thanks for the help. I will let you know how it works out.

 

[amphi]

Why did the wire to the alternator burn out?

From your description of how cranking slowed and stopped on it own, sounds as if the connections to the front battery became open due to heat. It also could have lost it's ground path thru the negative terminal block on the firewall.

See this thread on what happens when the front battery is disconnected (either side) during starter run-on:

http://www.steelsoldiers.com/showth...fter-Starter-Run-on-Explained-and-Illustrated

Double check the full ground path from the front battery all the way to the chassis and engine.

Since the starter didn't crank very long it might be ok.

Gary