My CUCV keeps blowing Starter Relay???

About a month ago I hopped in the M1009 and cycled the glow plugs. When the wait light went off I turned the key fully forward and nothing happend - I got a click from the starter relay but nothing from starter solenoid...

Out of frustration I furiously went between start/off with the key, and finally held the key in the ON position until something made a burning/crackling sound under the vehicle... I know I shouldn't have done that but it had been acting up for a while and I was desperate to figure out what was going on... It was behaving like a dead battery but both batteries were charged!

After tracing things around for a while I decided that the starter had in fact died. I removed it, took it apart and the brushes were lodged in the side of the starter --- it was definitley dead. It turns out my #2 battery was toast as well (had full charge, but no load) and this possibly caused the death of my starter.

Bought a 2nd starter at the shop, along with 2 new batteries - installed everything. After replacement car fired right up - but seems to have a slight delay (maybe 2/10 of a second) from when key is in "start" position to when the solenoid on starter actually engages... This seemed odd as it usually is INSTANT reaction.

I went out to the truck 10 days after replacement, turned the key and got similar symptoms. NOTHING happend. This time I was patient as I didn't want to burn up my starter. I turned the key off for 30 secs... Turned it back on, waited for glow plugs to cycle - and went to START position. Again no starter solenoid engagement but this time something popped and made an "air leaking" sound under the dash... I pulled the starter relay and replaced it with an AC40 relay from Napa.


This happened 2 more times, burned out the starter relay.

I don't exactly know what is going on here - I tried a few tests...

The next time the key wouldn't START the CUCV, I pulled the relay instead of cranking key a few times I then:

1.) Placed a heavy guage wire between the RED and Purple wires at the edges of the harness (to jump manually instead of using relay). The solenoid clicked, but wouldn't crank starter over - sounds like starter was locked up.

2.) Then using the same heavy guage wire, I cycled off/on the contacts 3 or 4 times pretty quick - the starter solenoid engaged each time, but ont he 3rd or 4th time it finally spun out the starter and the car fired right up.


PLEASE HELP ME FIGURE THIS OUT!!!

Does it sound like a bad starter?

A short somewhere in the harness???

I am stumped!!!!

Thanks to all in advance!

MuddWeiser said:

......
Bought a 2nd starter at the shop, along with 2 new batteries - installed everything. After replacement car fired right up - but seems to have a slight delay (maybe 2/10 of a second) from when key is in "start" position to when the solenoid on starter actually engages... This seemed odd as it usually is INSTANT reaction.......

Click to expand...

The starting system has no monitoring lights to show what's happening, so you must rely on your hearing.

The sequence of events is as follows:
Start key energizes starter relay, which energizes pull-in and holding windings of the solenoid (there are two windings within the solenoid). The pull-in winding moves the pinion gear to engage flywheel gear, solenoid relay contact closes and shorts pull-in solenoid winding, while the holding winding of the solenoid keeps contact closed.
The pull-in winding is grounded via the starter motor, so it turns while the pinion gear engages the flywheel gear.

This may help you troubleshooting, of course all wiring must be intact etc and starter relay rated for the job (20 to 50 amp continous).

RE: Re: My CUCV keeps blowing Starter Relay???

Well what seems odd to me is that using the key, the starter engages immediatley sometimes, and other times it has a slight delay or won't spin at all. When it won't spin, and I try it a 2nd time, the relay pops/hisses (kind of sounds like opening a bottle of soda)...

I am not really a mechanic so I don't know what to do!!!

Its really frustrating as of course this has to start happening a month before I am really going to need this truck when the snow starts falling!!!!

RE: Re: My CUCV keeps blowing Starter Relay???

Been reading alot about ground cables lately.
Maybe an intermitent ground problem?
Good luck

We've seen some switch failures in the civi models.

So I disassembled the lastest burnt up relay and the problem is that the one of the two contacts that get touched together to complete the 24v to the starter solenoid is popping out of the base and getting stuck in teh "closed" position. These are the contacts that bridge the 24v to the solenoid (the purple wire bridges with the red wire).




Where would I look for a bad ground?

Which switch are you talking about RE: switch problems?

? make sure both your engine and chassis are properly grounded to batteries with good cable. I hesitate to ask, but are batteries wired up for correct voltage for starter? 12v or 24v Lastly, make sure you have correct starter soleniod, I had one parts supplyer who was so sure that 12 and 24 v solenoids were the same, he sold me a 12 and told me it was a 24, it lasted a few minutes.

Re: RE: Re: My CUCV keeps blowing Starter Relay???

MuddWeiser said:

Well what seems odd to me is that using the key, the starter engages immediatley sometimes, and other times it has a slight delay or won't spin at all. When it won't spin, and I try it a 2nd time, the relay pops/hisses (kind of sounds like opening a bottle of soda).

Click to expand...

I wanted to know if you ever figured this problem out? I have the exact same problem. Last night I replaced the starter relay under the dash with a ford type solenoid so it could handle the amp load. The first few starts were perfect. Then later on I just get a click. 2nd try same thing and on the 3rd try it starts like normal. This morning the same thing. Two try's no good the on the 3rd it starts fine. From what I am hearing the starter gear is kicking out but the motor isn't turning. Now this is a brand new starter. I sure would like to figure this out.

RE: Re: RE: Re: My CUCV keeps blowing Starter Relay???

It sounds like you have a short somewhere. Feel the purple and red wires and see if they are hot. If so, the smaller wire to the starter may be grounding against the manifold or engine block somewhere. That wire is fed by the red wire coming out of the starter relay. It's happened a couple times with me.

An easy way to bypass the starter relay is to hook up a 24 volt switch in between the red and purple wire. I carry one in my truck in case the relay blows.

Also, do you have a set of manuals for your truck? If not, they are available on this site or I can email you a copy.

Where in Long Island are you? I'm not far, right near Asbury Park, NJ.

RE: Re: RE: Re: My CUCV keeps blowing Starter Relay???

Hey Mike. Yes I have all the manuals and I'm in Coram (Suffolk County). Well today after work I brought my truck inside to see if I could find a problem. A few people said it sounded like a ground to the engine so first I added a new 24" ground cable from the frame to the engine block. Sanded the areas down to clean metal and used star washers at the contact points. So now I know I have a good ground. Next I went under the truck near the starter. The small wire to the solenoid is not shorting out as I traced it to the top and it is fine. I then pulled on the battery cable at the starter and sure enough it moved. I took it off and cleaned the connection and reinstalled it. Then snugged it up and it still felt loose. It wound up being the nut under the battery cable that holds the stud that was loose. I retightened that and then reinstalled the cable to the solenoid and now everything feels good. I then drove it around about an hour with a lot of start ups in between and no hint of any trouble. So for the next week I will have my fingers crossed that was the problem and the problem is solved.

Out of the blue mine started to do the same, bake the starter relay under the dash. After spending a hour of chasing all off the wires involved, removing, testing, and reinstalling the starter, we pulled, cleaned and reinstalled the battery cables and...ta da... no more problem.

Good luck,

Lew VB

Having problems with my M1008.
Tried to start it this morning and it was turning over and then suddenly nothing.
Batteries are charged but when I turn the keys over, I get a clicking sound from the starter relay and also the glowplug relay.
I tried to jump the starter relay by jumping the red and purple wires but still no crank.
Took a test light and tested the starter while ignition hot but no power getting to starter.
What is the problem here?????

Starter , starter relay batteries 24volt etc etc

Gents,
I too have a Bunch of problems discribed in these posts and have yet to see any one with a difinitive answer as to what exactly is the problem. I went thru 3 starters 3 relays. and
still yet to hear this thing run. Any one have this really slow cranking that sounds like something mechanical is wrong ? Then change the starter out it cranks fine . then
after a few cranks either the relay burns or
the starter craps out . any one actually find a problem like this and the actual fix for this particular problem ?
I dont really see whats wrong with whats there , but this stuff is really unreliable and lots of folks swear by them (demographic ?)
Any one got the cure im all eyes on this one !
Thanks in advance to all who participate
and those who know ..teach !!!!!
regards
Dave

Hoolio said:

In the text about starting problems with cucv 24 volt units..Someone stated that a NAPA supplied Delco 40 relay works in the starting circuit...Is this correct?? I'd like to have a spare for just one of those mornings..If not , I guess Memphis Equipment has them...I'm a relative newbie to these trucks...I bought a 1986 M 1032 pickup recently..I'm a little skeptical about this 24 volt business mixed with 12 volt..Someone said the original 24 volt system makes for better winter starts..Is this true ??

Click to expand...

I guess I'll see tomorrow if this works, as I'm going to pick one up and try it.

From my experience with 24v systems, they do have better cold starts. Some of the guys on here will argue otherwise, but 24v is just far more efficient. As much of a pain this 24v/12v system is, I want to keep it.

hi guys i'm new here but have read a few posts and maybe can help as we have 3 moo9 and 1 moo8 at highway garage and i drive my own moo8.
i've worked on these vehicles and they are quite a bit different from the civilian issue.
if your starting system is stock military you must use 24 volt starter and 24 volt solenoid.12 volt parts store stuff will work but only for a while.usually the solenoid will self destruct first.clicking starters are usually bad connections or under charged batteries.hope this helps.

Problem. M1009. Starter Failed. Replaced with new 24 volt gear reduction starter. Started. Ran Good. Turned off engine. Went to restart. Would not start. Would not even turn over. Smelled electrial and observed smoke at terminal block near glow plug realy on firewall. Two wires connecting to left side of terminal block just above glow plug relay very hot. ? Have checked and batteries are good and grounds are good. Does anyone know what the two red/orange fuseable links connected to the terminal operate. Thanks.

Find a good starter & alt shop have them build nippendenzo 24V gear reduction starter as relay under the dash 40 amp is not enough 60amp works better no hassel at all. I did it to m1009 in feb also checked all wires for contac Pos+ & ground's -
just finish M1028A2 went through wire Harn, converted to work with cummins 5.9 12 valve still 2 alt 24V & 12V system
all like new also make sure the right side alt is isolated ground if not you will have back feed this will cause wire to melt or back
feed in to 12V system. Need more power.

cjtroutt said:

Find a good starter & alt shop have them build nippendenzo 24V gear reduction starter as relay under the dash 40 amp is not enough 60amp works better no hassel at all. I did it to m1009 in feb also checked all wires for contac Pos+ & ground's -

Click to expand...

What?
I get that you are saying a 40amp is not enough and a 60amp will work better. But the highlighted portion... I dont get.

Do you have part numbers for the larger relay? Will fit as an exact replacement?

Also having problems with electrical and batteries draining, need help.