Runaway Starter, but different with what wires not to pull

[Barrman]

Some back ground first.

Direct Drive 27MT 24 volt starter.

Rebuilt by a very good rebuilder a year ago next week after it wouldn't turn the engine anymore. Basically all internal parts new. New solenoid with "24V" stamped in the side of it.

I have never let the starter turn more than 5 seconds in the past year. The truck normally starts in less than 1, maybe crank to 2-3 if the engine temp is such that the plugs don't come on.

Basically, a good starter with very little wear.

Dog head relay installed when the starter was put back in last year.

Thursday after we had an Eagle Board of Review for one of my Scouts. I fired up the M1009 to go home. The engine started right up as usual. I heard a humming/whirring noise. Thinking alternator or power steering pump issues, I turned off the key. The engine died and the noise continued. Hmmm, then IT"S THE STARTER! clicked in my mind.

I tried the key again and the relay under the dash clicked each time I tried it. Starter motor continued to spin, but the engine wasn't turning over. I popped the hood, grabbed a flash light and went to pull battery terminals off.

I like to keep mine tight. None of them wanted to budge and my wrenches are in an ammo can in the back of the truck. I didn't want my expensive starter to burn up so I tried the terminal leads again. The front battery negative terminal moved and I eventually got it off. Starter motor stopped turning.

Now that it was stopped, I went running to the last other person left in the lot to ask for a drag home. 30 seconds to a minute later I was back at the truck. I saw lots of smoke and glowing red wires. By the time I got the wrenches out and the other 3 terminals off. It looked like the entire wiring harness was smoked.

I stood there thinking evil thoughts about all things mechanical, pushed the truck back a few feet so I could be towed and got the tow strap out. By that time, the smoke was gone.

I confirmed that no more wires were burning and tried to hook up the front cables so I would have lights and flashers for the tow strap trip home. No sparks, no noises and the lights worked. All the idiot lights came on when I turned the key too far trying to free up the steering wheel.

No problems on the 5 mile tow home. I pulled the battery terminals off, looked for anymore smoke and just went inside for the night.

Looking through the wiring diagrams the next day I realized what I had done.

Pulling the BAT 1 negative lead caused the BAT 2 8 gauge negative wire to carry all the load of turning the starter. Its fusable link burned at the engine wiring harness block over next to the glow plug relay.

The starter relay 24V feed wire also burned its fusable link at the firewall buss bar. Another 8 gauge wire.

The ALT 2 8 guage negative also burned at the engine wiring harness block along with another fusable link I never did figure out what circuit it belonged to.

So, the wiring wasn't a total loss.

What happened though? The starter motor had turned the engine and the solenoid had engaged the Bendix to make the engine start. The way it is supposed to work. Then, just the motor was spinning without the Bendix engaged. That to me means starter solenoid malfunction.

I could hear the starter relay under the dash clicking which while it doesn't mean it isn't sticking, doesn't point to it as the problem either.

I carry a spare starter I rebuilt a year ago in the back of the 1009. My mission Saturday was to fix all the wiring, drop the thought to be bad starter, test the system out with no starter installed and then put in my spare.

I was able to find a 10' roll of 12 gauge fusable link wire at our local Car Quest along with crimp on ring terminals just in case I didn't have enough already in my electrical kit. $10 spent.

Attached is a picture of all the burned links I cut out sitting next to each other. Once I had them all cut off, I got out my yellow crimp butt connecters and found they don't fit 8 gauge wire. Another trip to town and I found Car Quest part number SST80. That is a 10-12 gauge crimp butt connector that comes with no insulation. Just the way I like them. $2.00 spent.

Back home and everything got wired back up. The other attached pictures show the replaced fuseable links. They are clean, light blue and have red/pink shrink wrap on them. Yellow cover end terminals too. Pretty much the pictures show you which wires will burn if you just pull the front battery negative terminal during a runaway starter event.


I pulled the starter and made sure the power in wires weren't touching anything. I had Colton get inside once I hooked up the batteries and try the key. No voltage to the purple solenoid wire unless he was turning the key to start. Off and on half a dozen times. All working good. Has to be the starter solenoid.

I put a DVOM on the solenoid and could not find conductivity between the main power in to the solenoid and the power in from the solenoid to the starter motor. Hmm. I thought that was it for sure.

I hooked up some jumper cables, put my foot on the starter and used a screw driver. Worked perfect. Bendix popped right out and the motor spun right up. Again and again and again. Thats not right.

I tested my carry around with me spare and it did nothing. Good thing I didn't need it.

I had another spare and it tested great. I installed it and the truck fired right up. Except, the voltage meter stayed right at the yellow/green line. Now what?

I turned it off, checked everything with the alternators and it looked ok. Batteries 12.4/12.5 engine off and 13.7/13.7 with the engine running. It starts and I can live with a low charge just driving around town. One entire day spent fixing this thing and I still didn't know what failed, why or if my alternators got zapped in the regulator some. At least it runs and I can drive to work Monday.

This morning I checked the batteries and 12.7/12.7 what what I found. Fired it up and the needle went to the middle of the green. 14.4/14.4 on the batteries with the engine running. All good.

I still think it is the solenoid that failed. However, since the starter ran for at least 1 minute if not more. It might have smoked itself some. Back to the rebuilder it will go next week. Along with my thought to be good spare starter.

Sorry for the long post, but I wanted to cover all the facts and relay what was done. The lesson here is that nothing is for sure ok and pulling just one battery cable will cause troubles.

 

[doghead]

That is why I have been telling everyone, not to add a battery disconnect on the negative cable(especially for a starter run-on prevention plan).

I would guess your bendix drive stuck out for some reason, causing the solenoid to keep the starter energized. (was everything tight on your starter when you removed it?)

As I read the voltage was 13.7, I was thinking not good. Why it increased later, no clue. Most regulators kick in higher than 13.7(usually 14.2 or 14.4) I'd keep a close eye on them, for a while.

Great documentation.

 

[SouthernSteel]

So what was the root cause as i know im slow :]

 

[doghead]

So what was the root cause as i know im slow :]

The root cause has not been determined for sure.

 

[SouthernSteel]

ok i thought i missed something Doghead thats the only reason i made the comment i have something that might be of interest that might be an idea however this doesnt occur everytime my red m1008 has the doghead relay conversion done doghead is it possible that the relay might be apart of the problem (the 12 to 24 is defintely a load) now before anyone jumps its just an idea not in stone direct fact The relay does work but on occasion it will click but want start when u do it again it cranks it always sounds like the bendix gets stuck i have had it happen a few times was wandering if it might be related.also my red m1008 doesnt always shut off completely after u turn the key off it takes about 5 seconds before it cuts off i have a brand new igntion so im thinkin we both might be suffering from really corroded contacts possibly the steering column itself has a short not hijacking the thread but i few of my problems started kinda making me think after reading what he posted just curious :]

 

[doghead]

Your issues sound like , a bad battery cable connection and a bad shut off solenoid in the IP.

 

[SouthernSteel]

thanks doghead does that mean that even though i unhook my neg cable every nite that the starter might still have power

 

[Jersey4x4]

The bendix has a sprague in it so when the starter is engaged it will start the engine and just like if you held the key too long the bendix is kicked out by the flywheel rotation and the motor will still spin but the bendix drive will not be fully extended. I have had this happen and it sometimes can grind the chamfered part of the ring gear a little bit as well. This could have been caused by a burnt contact in the starter solonoid it self or the starter relay under the dash staying engaged caused by a burnt contact or as I recently found, the rod in the column broke and got stuck holding the ignition switch in the crank position.

 

[Barrman]

I do not know the cause yet. I did drive it to work this morning and the volt meter was where it should be. The truck will get driven today and maybe tomorrow. Then I will bring it into my class for my students to do ball joints, tie rod ends, front u-joints, turn the rotors and such all in prepping to take the ASE brake and ASE suspension steering test. My personal schedule won't allow me to get the starter motors to the rebuilder until maybe next week. I will post up what I find when I find it out.

 

[Warthog]

The ALT 2 8 guage negative also burned at the engine wiring harness block along with another fusable link I never did figure out what circuit it belonged to.

The four wires that burnt are the following:

3 BLU-2L - 24v wire from GEN2 positive terminal to the 24v Positive Terminal Block

3 BLU-2B - 12v wire from the rear battery negative terminal to the 12 ENG Wiring Harness Block

3 BLU-2H - 12v feed from the 12v ENG Harness Block to the ground terminal on GEN2

3 BLU-2M - 12v feed from GEN1 positive Terminal to the 12v ENG Harness Block

These are the wires that always seem to burn when ever the starter is a runaway.


I'm still betting that the solenoid stuck in the closed position and allowed the starter to turn without cranking the engine. Your rebuild guy should be able to verify this.

 

[Barrman]

The starter guy called yesterday. The solenoid had "severe arcing" inside it. That was the problem. Of course, the bushings and brushes needed to be replaced because the darn thing ran for a few minutes straight.

Just wanted to finish this one out.

 

[82ABNMP]

Battery cutoff switch

I have a question please...what's the proper way to mount a battery cutoff switch on the CUCV in order to avoid burning all the links and such when a situation like this occurs? And also so you don’t have to disconnect the batteries every time you want to work on something.

David

 

[Barrman]

Depends which you want to do. If you just want protection from a run away starter. Put in the recommended starter relay under the dash spoken about in the doghead relay threads.

If you want to stop the starter from spinning in a run away like mine, then a cut off switch between the big starter lead and the firewall buss bar will do it.

If you want to cut off both batteries in a hurry, then I would recommend a cut off switch on each ground wire. I say ground because the batteries are inter connected in several different ways. Just doing the end + and - will not stop power flowing.

However, for just maintenance purposes. You will be better off just pulling the cables off the terminals. It will make you clean and inspect them too.

 

[82ABNMP]

"If you want to cut off both batteries in a hurry, then I would recommend a cut off switch on each ground wire. I say ground because the batteries are inter connected in several different ways. Just doing the end + and - will not stop power flowing."

This is what I want to do. In all my trucks I replace the starter relay and all GP parts; but am more interested how to wire a cutoff that would cut all power while stored, for emergencies and for maintenance.
David

 

[gringeltaube]

The starter guy called yesterday. The solenoid had "severe arcing" inside it. That was the problem........

That "arcing" usually gets worse if the bat. voltage dropped too low (higher amperage)
Now, old and burned-out contact bolts & disk may cause that familiar "click-but-no-turn" condition but it is mainly NEW contacts that can literally weld together and even stay that way after power was disconnected!
There may be certain copper alloys that make that more difficult to happen but really the only part that separates the contacts after one releases the start switch is that little spring marked with the red arrow.
Now go out and compare these springs from different brands... like the cheap "chinchulin"-parts available everywhere vs. the original Delco-Remy....!


G.

 

[Barrman]

I really hesitated to write anything in the post above besides how to cut off just the starter. Here is why:

If your batteries go down while the truck is just sitting, something somewhere in the truck is shorted to ground and needs to be fixed. Fix the drain.

If you add a pair of moveable electronic switches into a system that at times needs every single amp and then more. Adding two possible resistors or fail points is not the best idea. What if one of them fails while you are out in the middle of nowhere on a cold dark rainy night? Walk is the answer.

Plus, there really is no easy way to just put switches on all the leads. Front battery - is easy. Pull that while the starter is turning and you get the pictures and damage this thread is about. Rear battery + will do the same basic damage. Those are the super easy ones to bolt in switches. ALT 2 charges + and - of BAT 2. ALT 1 charges the - of BAT 2 and through the ground the - of BAT 1. You really need disconnects at all 4 terminals and the ability to turn them all off at the same time while a load is being put on the system. Otherwise, the starter might live but an alternator might not.

I am going to think real hard about a starter motor only cut off. Because the solenoid that failed on me was new a year ago and I don't want to do this again next summer. I am not however planning to do a complete system cut off. No reason to since the starter is the only thing that needs both batteries. ( got rid of the GP resistor and am running straight 12V to them from BAT 1)

My reasons make sense?

 

[Barrman]

The solenoid was a new last summer Delco. Fully charged batteries with no slow start conditions. Thanks for the pictures.

 

[82ABNMP]

Cutoff

I really hesitated to write anything in the post above besides how to cut off just the starter. Here is why:

If your batteries go down while the truck is just sitting, something somewhere in the truck is shorted to ground and needs to be fixed. Fix the drain.

If you add a pair of moveable electronic switches into a system that at times needs every single amp and then more. Adding two possible resistors or fail points is not the best idea. What if one of them fails while you are out in the middle of nowhere on a cold dark rainy night? Walk is the answer.

Plus, there really is no easy way to just put switches on all the leads. Front battery - is easy. Pull that while the starter is turning and you get the pictures and damage this thread is about. Rear battery + will do the same basic damage. Those are the super easy ones to bolt in switches. ALT 2 charges + and - of BAT 2. ALT 1 charges the - of BAT 2 and through the ground the - of BAT 1. You really need disconnects at all 4 terminals and the ability to turn them all off at the same time while a load is being put on the system. Otherwise, the starter might live but an alternator might not.

I am going to think real hard about a starter motor only cut off. Because the solenoid that failed on me was new a year ago and I don't want to do this again next summer. I am not however planning to do a complete system cut off. No reason to since the starter is the only thing that needs both batteries. ( got rid of the GP resistor and am running straight 12V to them from BAT 1)

My reasons make sense?

Yes, mostly. The reason I ask is because the previous owner of one of my trucks installed a "pull off" type connection switch between the front battery and rear battery. I know this will not kill the whole system but what if you installed the same type of cutoff switch on the back battery? ie between the rear battery and the firewall?

Thanks, David

 

[Dave Kay]

The solenoid was a new last summer Delco. Fully charged batteries with no slow start conditions. Thanks for the pictures.

Barrman, now you've REALLY got me wondering... you say a new AC Delco solenoid went south in only few months time? What the heck could be the cause? I've always bought AC Delco stuff because over the long-haul it's proven dependable--- at least for me. Have you got any photos showing WHERE the solenoid was 'arching'? May be a clue there...

 

[Barrman]

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.