CUCV meltdown- Learning the hard way

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mtperkins

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So my wipers were not working last winter and i found a burned out fuse holder. While i was under the dash i found a accessory wire unhooked that i thought went into the fuse box. Well i plugged that in and i ended up with smoke under the hood. Unhooked it fast. Then my glow plug light would stay on while running.

Parked the truck for months because the glow plugs burned up.

Removed shorted out voltage drop that was feeding Glow Plugs 24v. Replaced the GP's.

Replaced GP relay. Wait to start light still stays on. I would unhook power to GP relay after i got the truck running.

Then the batteries would be dead. Found 5 volt short at the 24 suppressor. Removed that.

Next i hooked the GP relay back up and then tried to hook the batteries back up. SMOKE!!!! The blue wires (fuse link) at the 2 stud firewall engine terminal block melted. ( insulation only it seems)

I quickly unhooked the bat cables. unhooked the GP relay from this. Then hooked the batteries back up. Everything was fine. Hooked up GP relay. Used GP to start the truck. It ran and my stupid wait to start light was out finally.

HOWEVER!!! Now i have a 10 volt draw on the first battery.

I unhooked the GP relay and alternators. Still 10v draw.

Bash me for trying idc. But im just frustrated. What did i burn up now?




Matt

1986 CUCV

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cucvrus

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Hard to tell. You have a few things going on that make it hard to assist. What has been changed and what is as designed? Weak batteries are a big problem with the CUCV vehicles. More so than other vehicles. Not sure how to help from afar. Do you have the correct glow plug relay? Good Luck. I would be happy to help if I could see the whole picture.
 

mtperkins

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Thanks for the reply. Ok, any help is greatly appreciated. I am just stressing out from nearly catching my truck on fire!

items not stock are as follows :

  1. GP card has been changed to a push button for 7 years. 2 new alternators then as well. ( it worked fine )
  2. Burned up the 24v to 12 volt drop on firewall for glow plugs. removed it and got 12 volts form 2 stud firewall block above gp relay (this summer)
  3. 8 new AC delco 60G i think glow plugs. Removed injectors to get swollen plugs out. ( what a fun job) ( this summer)
  4. new chinese GP relay marked CUCV from EBAY- which works right now- i still have the old one i think its fine. ( last week)
  5. 2 new group 30 batteries ( last week)
  6. 115v block heater installed (last year)
  7. wiper fuse holder is burnt- i removed my add on fuse wire for now ( today)
  8. removed suppressor between 24v power and ground bar because it was giving me a 5 volt draw on 2nd battery. ( last week)

right now i have no smoke anywhere- truck GP work as they should, starts, runs good. I'm not sure if it's charging batteries because i took belts off to get new ones today. But i have a 10v draw on the first battery.

I will start removing fuses or blue fusible wires at the 2 stud firewall terminal until i find out whats causing the draw is my next move.
 

sneekyeye

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When you say 10v draw, what are you meaning and how are you getting that measurement? Usually parasitic draws are measure in Amps or miliamps, unless you're just measuring a voltage drop somewhere. My opinion would be perhaps there is something in your fuse panel that has melted together and is creating not a dead short but just enough for your voltage drop. Or maybe one of the diodes in the system has shorted out. You may also have a glow plug relay that isn't electrically isolated from the case of the relay itself and is grounding out. Long distance electrical diag is like throwing darts at CUCV electrical problem bingo cards. Can only be so helpful without staring at it and puzzling it over for a bit.
 

mtperkins

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Thanks for your reply.

I bought a new multi meter today that has amps as an option. When i measure draw i am putting my meter between the positive battery post (battery #1) and the positive cable.


How do i get the fuse box out to look at the back?


I have only found one diode so far behind the air cleaner. Hope to work on it some this weekend.

thanks everyone for the help.

Matt
 

dependable

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Getting fuse box out requires taking off two mounting screws from inside and release of 2 plastic clips. You also have to detach the engine side of harness from driver's side firewall. Usually that is not a problem area unless harness has been hacked, and if you take apart make sure to contacts are secure when reassembled. Clips are behind mounting screws, (just above pencil in pic)

The burnt fuse holder usually caused by arcing/poor contact w fuse. I guess you already attached a fuse holder, which is a good work around if contact is gone.

One hint on the wiper motor circuit; it is also connected to fuel heating in original filter housing. I had one 1008 where the fuel heater seamed to have melted wiper circuit. That particular truckIMG_1354.JPG had had the harness badly hacked by previous owner though, and ended up replacing the whole engine side of harness eventually.
 

mtperkins

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Thank you.

I've been sick with the flu and have not looked at the truck much.

New multi meter says i now have 0.13 amps of draw on the system.

Hopefully i get the new alternator belts on and everything works.

I will let ya know.

Matt
 

sneekyeye

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Just for comparison, when measured, I have 0.004A (approx) draw on my battery when the vehicle is off. The little bit is probably the LED for the usb outlet I have in the cig light all the time.
 

mtperkins

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Its been cold here. Froze my azz off playing with this beast. One of the new batteries was bad. hooked up a new one and it seems to be working sorta right. Glow plugs work, it starts. But now Gen 2 light is out and all the dash illumination lights dont work. 24.5 volts not running. 26.6 volts while running. my charging gauge died. Should i be seeing 28 volts running?
 

sneekyeye

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The alt lights in the dash are part of the circuit working the alternators. If the bulbs are bad or they dont light when it is not running, then that alternator wont charge. It could be as simple as cleaning the connections at your instrument cluster connector and bulb sockets.. Careful though, the plastic may be brittle.
 

mtperkins

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Thanks for all the help everyone! I'm down to just one problem now. Gen 2 light is on and not charging. I hope a little searching on here will provide some answers. I hope that alternator is not bad.
 

cucvrus

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Did you swap Gen 1 with Gen 2 and see if the Gen 1 light comes on? If not I think your Gen 2 is bad. I am glad the light is working. Good Luck. These generators are NOT expensive to have overhauled at a competent electrical shop.
 

dependable

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Alternators "going bad" is small problem, much more easily solved than wire harness mysteries. The parts in the alternator that most commonly cause failure are inexpensive and relatively easy to replace. But having rebuilt by shop is a good option if you don't want to bother.

Not a bad item to have an extra in stock as a spare, along with the starter, since both are not always easy to just buy at auto parts store.
 

sneekyeye

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You could rebuild the alternators yourself if you are handy. The parts will run you less than fifty bucks for the kit per alternator. I did it and it worked out fine. if you do though, be careful about separating the cases and removing the end bearings. They can stick, and you run the risk of breaking the aluminum case if you don't support it correctly.
 

mtperkins

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I will swap alternators and see if the problem does transfer. Where would one get these alternator parts? I know both my alternators came from E-bay about 7 years ago when i bought the truck.
 
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