Slave jumping

[Rich Johnson]

I left the parking lights on and the truck wouldnt start. So I started up the m38a1 and plugged in the slave cable. The CUCV acted like the jeep wasnt even hooked up. No respsonse in the voltage gage, it still read between red and yellow. I verified that my slave had power at each end and my adapter was good. Im baffled as to why this didnt work. Ive jumped HMMWVs before so I am a bit pissed off.
Was the jeep just too low a current with the2HN batteries for the CUCV? The CUCV starter wouldnt even turn over.

 

[davidkroberts]

you know you can usually jump a CUCV off with a civi vehicle if you put the cables on just the front battery. Works great and yes before the forum police get all huffy i did check it before i did it the first time and yes its just 12v at the first battery. it doesnt become 24v until the back of the rear battery. Ive done it when both batteries were almost dead.

 

[rnd-motorsports]

on the jump start! and for the slave not working have you ever used it before maybe the conections on the back need cleaned just not making contact!

 

[O.D. Fever]

I would say loose cable conection..

 

[ida34]

Actually, when jumping dead batteries you need to let them charge enough time to allow the 12 volt side to build up enough power to run the relays under the dash. For the 12 volt ignition switch to run the 24 volt starter and the 24 volt volt gauge there are two relays that are normally off until they get 12 volts from the ignition switch to turn on. If you let it sit and charge for a few minutes the batteries will charge in enough to allow you to activate the relays. BTW there is a third relay that energizes the alternator for the back battery.

Additionally, like David already stated, when you leave the lights on only the front battery goes down. Most likely the rear battery was just fine. You could have probably jumped just the front battery and had it start right away without having to wait for the 24 volt gen on the M38 to charge the front batteries up enough to work the relays. If the front battery is dead and the rear is charged then you would over charge the rear battery while charging the rear battery up. Again the charging only takes about 10-15 minutes so the imbalance would be too great. The cucv system addresses the issue of battery imbalance better than vehicles with only one alt. The only exception is the ambulance cucv which has one 24 volt alt but a battery isolator to prevent imbalance.

 

[Rich Johnson]

Ok..... I charged up each battery individually. My headlights seem pretty bright, my horn works nice and loud, and my truck still wont start.
Acctually is worse than that, I dont think the starter is working at all, or even getting power.
I turn the key and hear my glow modul engage, then the relay engage under the dash etc, I turn to start and nothing happens. No clicking or jiging indicating low batteries as I have expereinced with my ford truck. Also I have had starters die on me in the past in my ford, in 265,000k miles I went through 3 starters in that truck. This for some reason doesnt feel like a dead starter. Im starting to wonder if a starter relay or something cooked.
The truck was running fine, no signs of anything other that my leaky radiator. Its my daily driver, so I might not be going to work tomorrow.

 

[Recovry4x4]

Make sure it's in park or neutral. If that doesn't fix it, it will likely be the starter relay under the dash. There is a Doghead thread on modding this for more dependability.

 

[Rich Johnson]

Please elaborate on the Doghead thread mod thing.

 

[davidkroberts]

go to the cucv FAQ section and get the part number for the relay. Its under the dash beside the STE/ICE diagnostic. the relay is about 7 dollars if i remember right and they are very problematic. Personally i would just replace it ad hope for the best before you have to get into the more involved diagnostics

 

[2deuce]

When you turn the key to start does your volt meter move?

 

[K9Vic]

go to the cucv FAQ section and get the part number for the relay. Its under the dash beside the STE/ICE diagnostic. the relay is about 7 dollars if i remember right and they are very problematic. Personally i would just replace it ad hope for the best before you have to get into the more involved diagnostics

O'Reilly - BWD R3066
Autozone - Duralast 19952

It is a blower motor cutout relay for the same model year trucks. I just replaced one yesterday on a M1009, cost about $10. It does have an extra pin, but this is not a problem. Faster to fix/change then the Doghead mod, but not as a reliable relay system as that mod.

I would say loose cable conection..

I had this problem on a M1008, the bolt at the 24v block was loose to the + on the NATO plug. Once I tightened it up I was able to jump it. Check to make sure all the blots are tight on the 24v block.

 

[Rich Johnson]

Ok well, Im still stuck. I tested the relay, I put hands on it and turned the key to start, I can feel the relay engaging. So I pulled the plug and got a 10 gage wire and jumped red to purple. I got a nice arc the few times I did it. So I kinda think that what ever that goes to on the starter is likely shorted or dead.
Im betting I need a new starter at this point.
Man, this truck is killing me.
I got it this sumer with 50k miles and so far I have spent over a grand working on the tranny becuase it wouldnt stop leaking, tured out it was cracked, I had to replace the case. Then the radiator started leaking. Its shot and full of stop leak till I can afford a new one. Now this. I kinda wish I hadnt dumped my f-150 and just put a new trany in it instead of making this change.
My brakes still dont work right either. They go all the way to the floor if you step on them real slow like in a parking lot. Ive almost run into things several times waiting for the brakes to engage. Ive adjusted them so many times I cant count so I figure thats just how they are. And pulling a trailer I can barely stop the truck.

Well, I guess I will pull the starter out and take it in to get rebuilt or whatever. I know they are not plentiful or cheap. Funny too, I was going to buy an extra starter when I could afford it and throw it behind the seat. My friend has two extra alternators from a truck so he said he'd give them to me.

 

[SGT Estum]

I'm surprised nobody's said this yet, but...

The -20 TM has a really good troubleshooting section on this. IIRC, it's under Electrical Troubleshooting. I followed it and fixed my starting problem.


That said, one other thing I would check (off the top of my head) is the +24V 1-gage cable running from the +24V bus bar to the terminal on the starter solenoid.

 

[tennmogger]

Sometimes when trying to start a truck with low battery, the starter will initially move the Bendix out, engage the flywheel ring, then stop due to low current. Just not enough energy to spin the engine. If the Bendix stays there, the starter will draw current but might not turn over the engine, even with partially charged battery, or jumper.

Can you turn the engine over part of a revolution manually? If you hear a clunk near the starter, or the engine does not want to turn over, maybe that's what's going on.

 

[Screamin' Metal]

Gotta remember, on these trucks. they're washed alot and sometimes the grounds get corroded, so check for that first. As for checking your starter....all you need is 2 batterys and 2 sets of jumers....have a good handle on it when you try to spin it. If it spins with authority, the starters OK. If your brushes are good, shove her back it.
Clean all your connections, I mean all of them! Over on the Bussbar where everything hooks up also.
Good luck and keep us informed....

 

[Rich Johnson]

Well, I checked the relay and it seems to be working. I jumpered on the plug to get the celonoid to run and it just arced hard. I have a feeling the celaniod is toast.
So tonight I pulled the starter out. I got to say... that is one of the more difficult jobs I have done on an army vehicle. I wound up having to drop the drive shaft to get it out.
I found that the bar that runs from the celanoid back into the starter was broke right where it enters the starter. Not sure if I did it or if i was allready like that. The rear mounting hanging screw came out of the starter so the starter body kinda came loose and fell apart.
Seriously, what a pain in the ass it was.
Now Im going to take it to the industrial electric shop that used to rebuild them locally for the military bases around here.

 

[davidkroberts]

if that doesnt work you can use a 12v civi starter until yours is rebuilt. you just need to move the starter hotwire from the 24v positive buss bar to the positive terminal on the front battery.

 

[Screamin' Metal]

Semper Fi ! OK, when you go to put the starter in.....or take it out.....raise the truck up by the front bumper about 4 to 5 inches, OR, until the tire just starts to come off the ground (I use a hi lift farm type jack)....this will allow you to slide the starter in, sit it on top of your front spring behind your front wheel. Slide under the truck, with the starter sitting on top of the spring, pucker up, grab that heavy bitch and slide her into place and shove a bolt in itand just start it a few threads.
Now, I have trouble holding the heavy thing into place, so, I have a long piece of althread with a nut on it, about 2 1/2" longer than a regular starter bolt. That way, you can fish your shims in place, tighten up on the nut to raise it into place. When you get really close, just a few threads from being tight, put the other bolt in and just snug it up. Pull the all-thread out and shove that bolt in and just barely snug that one up. Now, you can put your support bracket on and tighten the others.
Now, this sounds like alot but I found this out the hard way, by doing it a bunch-o-times in the sand and rocks in foreign places and I can change one out in about 10 minutes.
Laying that heavy starter on top of that spring makes all the difference in the world....
Having to change a starter in the heat of the moment in a firefight, hot and sweaty, sand up your butt, dirt in your eyes, wrenches falling hitting you between the eyes....really makes you appreciate concrete floors and mechanics creepers, or even a piece of cardboard!
Hope this helps.....

 

[rnd-motorsports]

While you wait for the starter pick up a master cylinder and put it on bleed it sounds to me that it is bad by the way you discribe the barkes. Good luck with the starter!

 

[Rich Johnson]

Ok so I took my starter and the one I bummed off a buddy in and got them tested. Mine had a bad celonoid and I busted the field coil lead off so 150 bucks to rebuild it. My buddy's take off tested good so I put it back in the truck.
Well, whats the worst that can go wrong with this....I snapped off a bolt, didnt even torque it yet. Had to pull it all back out and drill the SOB out and easy out it. Buddy brought over a spare set of take off bolts.

Starter is in now, but half the time it goes click vooom. Instead of RRRRR start. So I think it has a weak celonoid. ****, I just cant win. Im going to toss mine back in when it comes back. I dont look forward to having to do this whole thing again.