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LMTV '04 M1078A1 starting issues

coachgeo

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After getting the starter on the bench, it's clear how important that little 10/32 nut is. Without it on the plunger, the plunger sticks too far forward to engage the magnetism of the solenoid. I put power to the solenoid in the bench and it won't pull the plunger cylinder inward until I push the plunger in another 1/2" which is where it would be held if the dam nut was still on there with its washers. This why I could get it to crank on the truck. Once the nut fell off, all hope was lost and trans-genders took to protest.

I'm going to see if I can put it back together and restore humanity.
is it a brass nut that 24v flows thru.... or ?? if not maybe just take the unit to a big tractor supply or Ace hardware so you can matched the bolt to a nut they have...... and buy the needed nut?
 

Ronmar

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After getting the starter on the bench, it's clear how important that little 10/32 nut is. Without it on the plunger, the plunger sticks too far forward to engage the magnetism of the solenoid. I put power to the solenoid in the bench and it won't pull the plunger cylinder inward until I push the plunger in another 1/2" which is where it would be held if the dam nut was still on there with its washers. This why I could get it to crank on the truck. Once the nut fell off, all hope was lost and trans-genders took to protest.

I'm going to see if I can put it back together and restore humanity.
Clean up the pitting on the disc and contacts, and it will probably be good for years...
 

MatthewWBailey

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is it a brass nut that 24v flows thru.... or ?? if not maybe just take the unit to a big tractor supply or Ace hardware so you can matched the bolt to a nut they have...... and buy the needed nut?
I found it on the floor. Once I stopped looking, there it was. There's a couple fiber washers that it sandwiches together and holds the spring that pushes on the copper disc. I have to fiddle with it bc I don't know how it goes back together exactly. The solenoid seems to work when the plunger is where it's supposed to be. The whole unit should work but now I have a suspect starter motor blaaa.

My buddy at the local country Napa is looking to see what might cross reference. I'll let everyone on here know what he finds. Maybe there's a newer alternative. He's a M900 series wrecker guy that's been in parades at the same time as me. His 6x6 wrecker is pretty sweet.

I'd like to keep this old starter as a spare once it's back together.
 

MatthewWBailey

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Clean up the pitting on the disc and contacts, and it will probably be good for years...
Yes it's quiet a thick piece of copper. The pitting is not really that bad. It was lightly stuck to both copper studs when I took the cover off the back. Easily popped off. I doubt that would've stayed stuck if the plunger was-still connected.

Your troubleshooting is much appreciated. I never had that happen with a starter before. I need to send you some KC steaks!!
 

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MatthewWBailey

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Clean up the pitting on the disc and contacts, and it will probably be good for years...
Again, really appreciate all your knowledge and help here. I've read more of your posts on this battery issue and made a draft sketch of electrical mods attached. I have 1 battery down but others are fine per the tester. All the terminations are clean.

Also found a NOS M0017703ME STARTER on eBay for $304. NAPA did not have an alternative. Mine is an "MD" and I'm having an electric motor shop test it then rebuild it. I'm also going to put some blue thread locker on the NOS starter's plunger nut since that was the cause of the old starter failure. I don't have a P81 cable attached so either Midwest removed it or it wasn't outfitted with one. So that's off the list of worries.

The idea on the sketch is to eliminate those possible spikes and brownouts. After reading that other thread about the cap failure with the LCBD disconnecting, makes sense to simply unplug it and take the disco out of the Truck power circuit also. With this layout below, I'll have a battery bank solely dedicated to the ECU/Trans and truck controls exclusively. Should be fairly stable voltage always. The other bank can run the starter and AIH and charge on permissive switch or timer once the truck is running and heated up. The NATO plug and disco would then only operate on the second isolated bank.

What are your thoughts on this? Sounds stupid or reasonable?
 

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Wingnut13

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With the sensitivity of the trans computer, I'm wondering why the designers stuck with the traditional vehicle power arrangement. We use isolated power sources all the time in industrial automation: battery backed/isolated dc power for solid state circuitry with separate power for large items motors etc. Seems that would be easy to achieve in this truck. The only big loads are the starter and air inlet heater. Separating them seems like common sense Enginerring and eminently feasible with the current state of power electronics. Or is this just "the army way" as my Dad used to say.
I’d like to see a thread dedicated to this. It seems so many problems come from the batteries and associated components that could be eliminated as you state above. Going to a battery bank and step down to run the 12v side seems like it would be the way to go.
 

Ronmar

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Dedicated power systems might be a little overkill. The systems you are talking about powering are pretty robust, otherwise we would be discussung their failures here regularly, and we simply do not, despite all the alt and batt issues we see. There are other ways to do this also, Newmar makes products for just this purpose, start-guard and nav-guard I think? But it addresses a non-existent issue IMO.

This also does not address the root cause of all the power and alternator issues, an alt not sized properly to deal with such a large battery bank.

If you simply remove 2 of the batteries, you drop the chance of the LBCD dosconnecting to virtually zero, as 2 batts, unless completely shorted and dead(cant even crank truck), would have a hard time overloading the alt to a point where the LBCD would disconnect, even when stone dead.

Removing the disco relay guarantees zero disconnects, while still retaining the capacitor spike absorbing/filtration capability. You can probably sell that disconnect on ebay for $$$(~$600 new). Or disconnect its control wire from the LBCD, leaving remote switched disconnect control from the dash and passrnger engine bay, which is a good feature IMO.

The LBCD provides the only automatic charging system monitoring(drives charging failure dash light) on any of these trucks. That would be an easy enough feature to add though with a simple voltage sense circuit driving the dash light. You could probably even make it flash:)
 

MatthewWBailey

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Dedicated power systems might be a little overkill. The systems you are talking about powering are pretty robust, otherwise we would be discussung their failures here regularly, and we simply do not, despite all the alt and batt issues we see. There are other ways to do this also, Newmar makes products for just this purpose, start-guard and nav-guard I think? But it addresses a non-existent issue IMO.

This also does not address the root cause of all the power and alternator issues, an alt not sized properly to deal with such a large battery bank.

If you simply remove 2 of the batteries, you drop the chance of the LBCD dosconnecting to virtually zero, as 2 batts, unless completely shorted and dead(cant even crank truck), would have a hard time overloading the alt to a point where the LBCD would disconnect, even when stone dead.

Removing the disco relay guarantees zero disconnects, while still retaining the capacitor spike absorbing/filtration capability. You can probably sell that disconnect on ebay for $$$(~$600 new). Or disconnect its control wire from the LBCD, leaving remote switched disconnect control from the dash and passrnger engine bay, which is a good feature IMO.

The LBCD provides the only automatic charging system monitoring(drives charging failure dash light) on any of these trucks. That would be an easy enough feature to add though with a simple voltage sense circuit driving the dash light. You could probably even make it flash:)
That makes sense. It's a simpler fix than mine too. I'm gonna try the 2x group 31 batteries first, as you've said on other threads, and pull the control cable from the LBCD. I'm still going to put a manual switch in line with the AIH solenoid control wire since I use the engine block heater all the time in winter. That pulsing of the AIH drives me nuts when engine is already running.
 

MatthewWBailey

Thanks for this site. My truck runs great now!
Steel Soldiers Supporter
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Location
Mesa Colorado
Dedicated power systems might be a little overkill. The systems you are talking about powering are pretty robust, otherwise we would be discussung their failures here regularly, and we simply do not, despite all the alt and batt issues we see. There are other ways to do this also, Newmar makes products for just this purpose, start-guard and nav-guard I think? But it addresses a non-existent issue IMO.

This also does not address the root cause of all the power and alternator issues, an alt not sized properly to deal with such a large battery bank.

If you simply remove 2 of the batteries, you drop the chance of the LBCD dosconnecting to virtually zero, as 2 batts, unless completely shorted and dead(cant even crank truck), would have a hard time overloading the alt to a point where the LBCD would disconnect, even when stone dead.

Removing the disco relay guarantees zero disconnects, while still retaining the capacitor spike absorbing/filtration capability. You can probably sell that disconnect on ebay for $$$(~$600 new). Or disconnect its control wire from the LBCD, leaving remote switched disconnect control from the dash and passrnger engine bay, which is a good feature IMO.

The LBCD provides the only automatic charging system monitoring(drives charging failure dash light) on any of these trucks. That would be an easy enough feature to add though with a simple voltage sense circuit driving the dash light. You could probably even make it flash:)
So finally it's all back together today. New starter installed, 2 batteries removed. The AIH is temporarily unpowered at the solenoid until I can rig a switch. The battery analyzer from pulse tech showed 3 batteries at 65% and 1 at 40%. I charged the 2 I left in there. Truck fired right up no problem although I had the block heater going all day. Its 20F outside. No check lights and voltage is right on 28. Everything seems peachy.

After this 12 days of Xmas worry, I needed to take a drive and press down the Asphault. Lots of deer out but they run directly away from this truck regardless of where they are. Passed 2 county Sherrifs doing a speed trap down the road from me and they got the air horn and a waive on the way by🤠.

Drove 30minutes, came back and checked the 2 batteries are now showing 100% and 90% on the analyzer. I'd have never thought to Remove 2 batteries to fix that problem so thanks for the expert direction.
It's interesting that this is the only social media I do. Hmmm.🇺🇸
 

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MatthewWBailey

Thanks for this site. My truck runs great now!
Steel Soldiers Supporter
835
1,519
93
Location
Mesa Colorado
Dedicated power systems might be a little overkill. The systems you are talking about powering are pretty robust, otherwise we would be discussung their failures here regularly, and we simply do not, despite all the alt and batt issues we see. There are other ways to do this also, Newmar makes products for just this purpose, start-guard and nav-guard I think? But it addresses a non-existent issue IMO.

This also does not address the root cause of all the power and alternator issues, an alt not sized properly to deal with such a large battery bank.

If you simply remove 2 of the batteries, you drop the chance of the LBCD dosconnecting to virtually zero, as 2 batts, unless completely shorted and dead(cant even crank truck), would have a hard time overloading the alt to a point where the LBCD would disconnect, even when stone dead.

Removing the disco relay guarantees zero disconnects, while still retaining the capacitor spike absorbing/filtration capability. You can probably sell that disconnect on ebay for $$$(~$600 new). Or disconnect its control wire from the LBCD, leaving remote switched disconnect control from the dash and passrnger engine bay, which is a good feature IMO.

The LBCD provides the only automatic charging system monitoring(drives charging failure dash light) on any of these trucks. That would be an easy enough feature to add though with a simple voltage sense circuit driving the dash light. You could probably even make it flash:)
Does the LCBD cap spike absorbing capability provide enough to combat a bad alt regulator? I've noticed that my voltmeter is spiking to 30+volts on occasion (runs at 28 mostly), which accounts for the 3503 code I'm getting on the wtec display fault code memory #2. However Not sure if the analog guage is just bad. The regulator is new ($800 from Midwest) but it's worrying me. I'm going to put my fluke on max record and see what the spike is. I'd have thought the battery and cappys would keep that from happening.
 

Ronmar

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Does the LCBD cap spike absorbing capability provide enough to combat a bad alt regulator? I've noticed that my voltmeter is spiking to 30+volts on occasion (runs at 28 mostly), which accounts for the 3503 code I'm getting on the wtec display fault code memory #2. However Not sure if the analog guage is just bad. The regulator is new ($800 from Midwest) but it's worrying me. I'm going to put my fluke on max record and see what the spike is. I'd have thought the battery and cappys would keep that from happening.
Not a clue if it can absorb that, the fact you are getting a trans code prettymuch confirms a spike and it not being absorbed. This could be a diode breaking down in the rectifiers in the alt chassis...
 

GeneralDisorder

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First off - stop buying anything from MME. $800 for a 100A regulator is robbery.

Check out my thread on the topic of OVCO:


And the carnage inside the LBCD:


Try bypassing the LBCD first - unplug it's cannon plug and put the load cables on the batt studs for the respective voltages. This will disable the LBCD and that will tell you if it's the cause of the OVCO. It certainly could be in my experience.
 

MatthewWBailey

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First off - stop buying anything from MME. $800 for a 100A regulator is robbery.

Check out my thread on the topic of OVCO:


And the carnage inside the LBCD:


Try bypassing the LBCD first - unplug it's cannon plug and put the load cables on the batt studs for the respective voltages. This will disable the LBCD and that will tell you if it's the cause of the OVCO. It certainly could be in my experience.
Wow both those were entertaining reads. I think I saved 20 new bookmarks for later! I keep forgetting that LBCD is under there. Luckily I'm changing a cracky looking front tire which had no DOT label, so the spare tire crane is already lowered. I was looking at that heat sink LBCD knowing I was supposed to look at those terminals right after the starter mishap.
I will try that bypass immediately. I've not had it switch off or show "charging system" light since I dropped out 2 batteries and I just took a 180mi run to test the Eco hubs last weekend.
I'm curious to see if that ground connection is loose in the connector like you observed.
FYI, I'm closing in on that ECU. I got a set of 3.90s coming from Memphis. I want to do those with a rear Detroit locker, and service the front hubs all at the same time. Project list is getting bulky.
 
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Lostchain

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Does the LCBD cap spike absorbing capability provide enough to combat a bad alt regulator? I've noticed that my voltmeter is spiking to 30+volts on occasion (runs at 28 mostly), which accounts for the 3503 code I'm getting on the wtec display fault code memory #2. However Not sure if the analog guage is just bad. The regulator is new ($800 from Midwest) but it's worrying me. I'm going to put my fluke on max record and see what the spike is. I'd have thought the battery and cappys would keep that from happening.

The first thing I would do is disconnect the harness from alternator to the voltage regulator and thoroughly clean all the connecters on both sides. I just had a situation on the bench with a 100A alternator that was unstable holding voltage with pulsing spikes and I swapped to a new VR which immediately cleaned up the problem. I then went back to the original VR and the pulsing behavior had vanished. I think the plugging and unplugging of the harness was able to get some fresh copper on the pins as they looked a little oxidized and there was no dielectric grease in there..
 

MatthewWBailey

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The first thing I would do is disconnect the harness from alternator to the voltage regulator and thoroughly clean all the connecters on both sides. I just had a situation on the bench with a 100A alternator that was unstable holding voltage with pulsing spikes and I swapped to a new VR which immediately cleaned up the problem. I then went back to the original VR and the pulsing behavior had vanished. I think the plugging and unplugging of the harness was able to get some fresh copper on the pins as they looked a little oxidized and there was no dielectric grease in there..
This is the exact response I had today. I removed the LBCD from the power circuit bc of other threads. Then ran the truck. I was getting 29.2 to 27.3 with 2 spikes at 33.4 and 33.15 over 30 minutes of truck idling. The voltmeter is wavy between those first numbers. I shut it off, pulled the cable (as you suggested) on the VR and hit it with CRC and some paper shop towel reaming. Looked clean. Put it back on and now it's rock solid at 28 on guage. I did turn off the battery disconnect thou. DMM is saying 28.4 - 27.9.

Do you know if these VR's have any memory/learning? I'm wondering if the battery disconnect is resetting them? Just a thought.
 

MatthewWBailey

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They do not appear to be that inteligent…
As they are microprocessor based, they have to be using a PID control function. It's the standard loop control. And The I and D terms need some level of recording into a memory stack in order to function. I wonder if the E switching resets the whole memory stack. When PID's get out of sorts and start cycling, I've found in PLC work that resetting the I data especially, makes them recalculate and settle down.
 

Lostchain

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This is the exact response I had today. I removed the LBCD from the power circuit bc of other threads. Then ran the truck. I was getting 29.2 to 27.3 with 2 spikes at 33.4 and 33.15 over 30 minutes of truck idling. The voltmeter is wavy between those first numbers. I shut it off, pulled the cable (as you suggested) on the VR and hit it with CRC and some paper shop towel reaming. Looked clean. Put it back on and now it's rock solid at 28 on guage. I did turn off the battery disconnect thou. DMM is saying 28.4 - 27.9.

Do you know if these VR's have any memory/learning? I'm wondering if the battery disconnect is resetting them? Just a thought.
Oh that’s great to hear! As far as I can tell there is no memory in there. On the test bench I reset power multiple times to the VR and it didn’t make a difference until I messed with the VR harness.
 

Ronmar

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I would say fluctuations would be as likely a poor/weak connection as a failing component. As I recall General found a bad connection just inside the front case where the Regulator connection is located…
 

MatthewWBailey

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I would say fluctuations would be as likely a poor/weak connection as a failing component. As I recall General found a bad connection just inside the front case where the Regulator connection is located…
So if all connections were 100% in theory, AND the regulator is new or not faulty, AND the load on the PDP is constant, then the Voltage at X3 and X4 should be 28.0 and 14.0 steady with no fluctuation? Or maybe +\-0.5 offset but still steady? That'd be my expectation as the circuit designer. Im wondering how adaptive the process-control of the VR is and if some of the voltage weirdness I've seen is not evidence of a bad connection or bad VR, but actually normal response prior to the regulator self correcting?
 
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