FMTV starter issues

[emr]

Yea , they will not be in the system as long as the good ol" trucks were, When the last warrenty's run out they may be in the auction lot.....But they sure do ride nice to me.......thanks for being cool with my post....

 

[Army Ed]

no problem,o i will never argue as far as ride quality..they are outstanding.As far as keeping the vehicle simple for quick easy fix's.IE on the side of the road on a convoy ect.To technical as far as a military truck goes...we need more M818 type vehicles.....simple...effective durable and reliable and easy as **** to maintain

 

[saddamsnightmare]

December 12th, 2009.

Army Ed:

Sounds like the ground connections are bad and/or the starter relay and solenoids are worn. Chances are you fellows are starting them a lot more times daily then we do with our older M35s, and yet you are getting the same illnesses our trucks have. I have not been overly impressed with the FMTV design, as I think it has less room to grown in weight and add ons and it is overly complex for the job. Besides, which, don't rear end anything big in that cab......
If they have the solenoid on the starter motor and a starter relay, i would check all 24VDC connections for oxide or dirt and clean them (with the batteries disconnected) chances are you will find your problem that way. Good luck and thumbs up, I'll trade you a running M35A2 in my icon for an FMTV in same shape if you FOB it to Paris, TX. Then again, maybe not, the deuce doesn't need a PH.D. and a computer to find its ills.....


Cheers,

Kyle F. McGrogan

N.B. Have your Quartermaster get Unimog 1300L's you'll be better pleased.

 

[sandcobra164]

When I was in, I had a LMTV that would do the same thing. We would have to wiggle one of the circuit breakers (can't remember which one but probably could if I was looking at it). It would have this problem at least once a week and the mechanics never could fix it. Once started, it always ran pretty good.

 

[fastsailor]

solved my intermittent start problem

under the passenger side kick panel is a Alison relay box I traced my short to one pin in the connector to that box i used a needle to bend all the female ports a bit tighter

the one pin i found the fault in had evidence of arcing so it could cause an intermittent problem until you kick it or hit the dash

hope this helps others

 

[Mike Wryley]

I realize this is an older thread, but I had an issue a few weeks ago where a M1083A1 would suddenly not start after sitting inside for a couple weeks. Pressing the start button would make a click, but that was just a small contactor for the solenoid. Turns out the solenoid was stuck because a little moisture got in the works (flywheel housing doesn't breath well
apparently) and the plunger has such a crap plating job that it was all corroded. It was disappointing to see the poor quality of the chrome plating and resulting pitting. I did a major cleanup of the entire starter because anything mild steel was toast. Probably need to verify that the vent hose isn't plug as well.

 

[Txbikecop]

I was driving our LMTV back from Fort Polk when I stopped for fuel. when I went to start the truck, the same thing happened that you described. I'm new to steelsoldiers and realize the post was started in 2008, but was wondering if you discovered the problem. I used a screwdriver and attempted to bypass the solenoid and all I managed to do was turn the starter, but it wouldn't engage. A mechanic came out with the starter pulled from one of our other LMTVS. After installation it did the same thing. The mechanic put the meter on the starter and had me bump it from the mechanic's controls (pass side) a few times. On the fourth time the starter turned over and the truck started. The mechanic said he had done nothing other than place his leads onto different connections. I killed the engine several times and started it back up several times. When we returned to town, they carried the starter and had it tested and the testers said it was a bad starter. Since the other (used) starter did the same thing I'm not totally convinced its the starter ($400 to rebuild).

I've read some of the prior posts and was wondering if anyone had any positive results with the posted suggestions. I'm relaying what I've read here to our mechanic.

FYI - I'm a police officer and I administer our state's 1033 program for my department. The 1033 program is how we obtain military surplus for use in our day-to-day operations. I really like "my" LMTV. We ran our trucks (two 2.5 tons and a 5 ton) 24-hours a day for five days straight during Hurricane Harvey (we're in Southeast Texas, about 20 minutes from the Gulf of Mexico) performing high water rescues and evacuations. The deepest I ran my deuce and a half in was between 4' or 5' feet. We didn't encounter any issues other than getting handicapped or elderly into the backs of the trucks - I'm working on a remedy for that now. I feel the starter problem was a result of the high water operations, so I'm thinking it's a matter of time before the other trucks start having problems.

 

[Suprman]

On the starter solenoid the small post closest to the block is the positive. Get a clip lead on there and then touch the other end to the big 24v connection on the starter. If the starter does not work properly then its bad. Its considered a Cat part and as such its expensive unfortunately. I see alot of starters go bad and they do that intermittent thing.

 

[NDT]

The A1s suffer from solder joint problems in the PDP due to lead free solder. These can be very intermittent and temperature/humidity dependent.

 

[aleigh]

Fast forward 4 more years, and I am having this exact issue on my A0.

 

[Reworked LMTV]

The A1s suffer from solder joint problems in the PDP due to lead free solder. These can be very intermittent and temperature/humidity dependent.

Lead free solder sux. It is a nightmare to solder with.

 

[Reworked LMTV]

Is this an active unit asking on steel Soldiers? If so u need to go back to school. Sorry But I would be embarresed, if it is a hobbiest who owns a bunch of these i am sorry for the confusion...Randy

-1 spelling

 

[Ronmar]

Fast forward 4 more years, and I am having this exact issue on my A0.

One question I didn’t notice in my rapid scan of this old thread, was what EXACTLY is going click when you push the starter button? That will tell y0u a lot about where to look next...

 

[aleigh]

The start relay on the fuse panel presumably. That's where it sounds like it is coming from. The first time this issue happened for me, it was 2am in a blizzard on a 2000 mile trip. I had to call a truck out to run enough air to get the cab up enough because my manual pump is broken. It started OK with a screwdriver and then acted normally for a long time (months), but then it's just happened again. I do know it's not the batteries, I load tested them all and you can tell because the voltage gauge doesn't budge when you hit the button. I didn't get around to trying to screwdriver it this time, and even if it works, I'd rather actually fix the issue, so I like it broken if that makes sense. This happened to me on a 300 mile trip towing a M1082 and thank god it worked fine the entire trip, and then died the very NEXT time I tried to start it at the final destination.

And yes, I have been through all the relays & fuses. It's probably the wiring somewhere or the solenoid. I haven't tried hitting it or measuring the wire on the solenoid to see if it's getting power from the button, todo items. The other thing that cropped up is that my start inhibit switch is open regardless of pressing it, like it's broken. But my understanding is even if it was inhibited it would still crank, just not fire because no fuel. I don't know if it's supposed to be NC or NO in the operating position, I have not gotten into the schematics yet, but my guess is that wasn't the issue. I tried jumpering the wires to the switch regardless, did not fix.

TCM/VIM/whatever is good, shows neutral.

 

[simp5782]

Go with a gear reduction unit and delete that solenoid from the system. Use another type of solenoid with a manual switch to turn on whatever else that solenoid is doing if it has other things to power besides starting

 

[aleigh]

When I say solenoid, I mean the high-amp solenoid/contactor that is twinned with the starter. It's one unit I believe, the starter+solenoid, but I have never tried to tear one down. Tangentally, I want the truck to be original. If something is wrong, I'll repair it. Just need to find out what it is.

 

[Ronmar]

The start relay on the fuse panel presumably. That's where it sounds like it is coming from. The first time this issue happened for me, it was 2am in a blizzard on a 2000 mile trip. I had to call a truck out to run enough air to get the cab up enough because my manual pump is broken. It started OK with a screwdriver and then acted normally for a long time (months), but then it's just happened again. I do know it's not the batteries, I load tested them all and you can tell because the voltage gauge doesn't budge when you hit the button. I didn't get around to trying to screwdriver it this time, and even if it works, I'd rather actually fix the issue, so I like it broken if that makes sense. This happened to me on a 300 mile trip towing a M1082 and thank god it worked fine the entire trip, and then died the very NEXT time I tried to start it at the final destination.

And yes, I have been through all the relays & fuses. It's probably the wiring somewhere or the solenoid. I haven't tried hitting it or measuring the wire on the solenoid to see if it's getting power from the button, todo items. The other thing that cropped up is that my start inhibit switch is open regardless of pressing it, like it's broken. But my understanding is even if it was inhibited it would still crank, just not fire because no fuel. I don't know if it's supposed to be NC or NO in the operating position, I have not gotten into the schematics yet, but my guess is that wasn't the issue. I tried jumpering the wires to the switch regardless, did not fix.

TCM/VIM/whatever is good, shows neutral.

Good information. The transmission via the neutral start relay provides 24V to the start relay K1 In the PDP. The start button provides a path to ground to energize K1, via the contacts of the starter lockout relay(K24) which disables the starter once the engine has oil pressure. That is the most complex part of the start circuit, so K1 clicking in the PDP when you push the button is a good thing.

K1, when energized sends 24V from the 24V test point(X1) in the PDP down to the coil of the Auxiliary start relay on the drivers frame rail next to the starter. The other side of the aux relay coil connects thru the starter thermal switch and on to ground to complete the circuit. The thermal switch is often bypassed with a jumper in the connector on the end of the harness that runs to the starter port, or with the harness removed completely and that side of the aux relay coil connected directly to ground. When you push the start button and K1 goes click, the aux relay on the frame should also go click So you need to listen or feel for that...

The aux relay connects 24V from the starter solenoid terminal to the coil terminal of the starter solenoid to energize the solenoid and crank the starter... if the aux goes click, you need to confirm it’s contacts are making the connection to power the starter solenoid, or the starter has issues...

 

[aleigh]

Thanks Ronmar, I am sure that's in the TM but you just saved me a ton of time.

 

[Ronmar]

Thanks Ronmar, I am sure that's in the TM but you just saved me a ton of time.

No worries, I have gone over this circuit with so many, I pretty much have it memorized