Electrical Issues

Discussion in 'General IH Tech' started by dbswissy, Dec 13, 2010.


  1. dbswissy

    dbswissy Farmall Cub

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    I was driving home from work today. Half way home, my engine hesitated and then cut out on me. I lost all electrical power. I smelled smoke (electrical) and then got smoke coming into the cab. I pulled over immediately (ironically it was a fire station). Smoke was poring out from under the hood. I popped the hood and found the smoke was coming from the negative terminal on the battery. The chassis ground cable was fried and had burned through its plastic. I tried to pull the cable off, but burned my fingers. The connecter burned through and it disconnected itself from the battery. Gravity pulled it down and I watched it melt a 2" hole down the side of my battery. :oops:

    So, my wife pulled my home and I'm inspecting it now. The one thing I found that was interesting was that my ground cable that goes to my engine block was no longer connected. No bolt no nothing. It's just dandling there. I had a thought just to hook it up and see if that was the problem (perhaps a loose bolt that finally gave way and is lost on the road), but I figured I'd better post here first to see if any of you have any suggestions. I don't want to hook that ground up if there's a big possibility that there is a short somewhere that could cause a fire and make the damage worse.

    I examined under the instrument cluster, steering column, radio, dash, etc and could not see any signs of a shorted wire. I checked there first because I noticed smoke first in the cab. I could have come from the engine compartment, though.

    What do you think? Should I be suspicious about another short somewhere in the system? Would the main ground cable coming off the block be enough to fry the other ground?
     
    Last edited: Dec 14, 2010
  2. Jay Tabor

    Jay Tabor Banned

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    trace the + cable, it is shorting out somewheres.
    or you reversed the battery cables..
    or the battery reversed polarity..

    next time dont stand there looking.
    if the battery decides to explode-------- you get a face full of acid..
     
  3. dbswissy

    dbswissy Farmall Cub

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    Reversed polarity? Everything has been working fine up until half way home from work. Can that happen while driving?

    I realized it was a dangerous situation, so I did what I could quickly. I had visions of my car going up in flames, so I figured I needed to do at least disconnect the battery.

    I'll start looking around for short on the + side. That's a lot of wire!
     
  4. Dennis Bernth

    Dennis Bernth Moderator Staff Member Moderator

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    Not really so much- it's not going to be a fused circuit, or the fuse would have popped long before you melted the ground cable. And it's going to be a heavy duty wire in order to carry enough amps to cause that much havoc with the ground cable. I'd start with the infamous bulkhead connector, although you didn't post what your vehicle is; I'm assuming Scout II since that is the predominant ride around here, but if it's different let us know. Especially if you have a pre-78 Scout II, the BHC is a problem area, the large blue wire from the alternator to the ammeter and then back out runs more current than the connector IH used can handle. I'd just start looking at the biggest wires first; wouldn't be the first battery cable I've seen that got loose and laid on the exhaust until the insulation burned off, then instant short.
     
  5. Ronmc1954

    Ronmc1954 Binder Driver

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    X2 on the + cable, I rememberwhen I re-installed my tranny and got the batt cable pinched between the motor and bell housing, it took 3 days before it actually started to short. Did pretty much what you discribed with both pos and neg cables.

    Ron
     
  6. Allan E

    Allan E Lives in an IH Dealership

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    Nothing should be able to carry more current than the ground cable, because everything passes through it. This is not necessarily true of the (+) cable, but from the factory, it is. We tend to modify our electrical systems by running things hot off the battery, but normally there is the battery cable to the starter terminal, and that's where the charging system and everything else tap in to the system. The ground cable, however, is normally the only path of any significance to the negative terminal.

    My first reaction is to ask if there were additional grounding wires on the ground cable terminal. Without a ground there simply is no current, period, so...

    Based on that train of thought, losing the ground cable could cause the melted cable end. In fact, without those additional wires, with no ground cable connected to the battery, there is no other explanation. You simply lost most, but not all, of the negative battery cable, or more accurately, what was being used as the negative battery cable.

    Next step is to ask whether there was (a) actually a load causing the problem, or if (b)the smaller wire(s) trying to do the job of the ground cable are the culprit. The most simple explanation is (b).
     
  7. dbswissy

    dbswissy Farmall Cub

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    This is what I was thinking, too, Allen. There are no other grounding wires on my ground terminal. It would make sense that the main ground of the battery to the engine block carries an extreme amount of load simple because it is a very heavy gauge wire. If that wire were to disconnect while the engine is running (and the alternater is running), then all of that current would have to go through the smaller gauge wire. The smaller wire would have a greater resistance and thus more heat produced...in this case, enough to burn through the plastic shielding.

    I'll look around at some of the heaver gauge + wires, but it seems to me that if they shorted out, then the damage would not be seen on the ground wire but on the + wire with the short.

    I feel a bit better jumping into this now. I'm 80% sure I can reattach the main ground wire and everything will be ok.

    Oh and we are talking about a Scout II, 1973 with a 1979 345. Should have mentioned that.

    And one more question: since I'm dealing with a loose, dangling wire...where is a good place to attach that main ground wire to a 345 engine?
     
    Last edited: Dec 14, 2010
  8. 250gibson

    250gibson Binder Driver

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    What probabally happened is that the cable from the battery negative to the head became frayed internally, either from twisting or some other stress. This caused what was left to carry all of the current. Due to the small guage of what was left of the negative battery cable, the increased resistance and high current caused it to heat up and burn. The ground wire from the frame/body to the engine shouldn't cause this. That would cause intermittant ground problems which usually lead to things not working right, ie blinkers, tailights, guages, etc. Current cannot flow unless it has somewhere to flow to. Your case was the current had somewhere to go, just not a large enough path to travel through
     
  9. Joe D.

    Joe D. High Wheeler

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    Interesting problem. Usually, the engine won't start without the big ground wire attached. But, if it fell off while driving, the small ground wire would easily handle all the rest of the current without failing.

    Almost for sure your positive cable is shorting somewhere, or else the battery bounced and the positive lug touched some steel. If it was the blue charging wire that was shorting, then it would be burnt up as badly as the ground wire.

    Does the negative wire still have it's lug end? If not, then I bet the wire burnt off where it enters the connector. If it is there, then I bet it was at least touching the engine, enough to provide a supplement to the small ground wire, until it was hit by a massive blast of current.
     
  10. Jay Tabor

    Jay Tabor Banned

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    after reading and rereading and deciphering. yes i agree with Allan....

    of course proper maintanance would have found that long before it became a problem . .
    so make yourself, or BUY new 1-0 or 2-0 CABLES for ground and positive
    the + cable gets 3/8th" eye on one end and a 5/16th" eye on other.
    - cable gets 5/16th" eye on both ends.
    I use a large washer with bolt to hold the engine end of - CABLE to the engine for maximum contact, least amount of resistance and less chance of broken CABLE.
    clean off the batt. studs and starter stud and engine where youre gonna stick the ground - CABLE to.
    get you some 8, or 6 gauge WIRE and make some grounds to run from frame to batt - .
    the front of drivers side head V-8 ENGINE is where - CABLE ground is attached to.
    what I do is put some 5/16th [ - negative] and 3/8th [positive +] stud battery clamps on the - , + batt. posts. and attach the CABLES to those clamps' studs.
    its easy to put on several CABLES and WIRES with EYE terminals on the battery clamp studs, tighten with a wing nut, for a better connection than slipping a eye wire terminal under battery post clamp tightening bolt/nut..
    and--
    in case of chinese- side- of- road -fire- drills, its quick -easy -and fast to open hood, twist off wing nut and pull the cable off the batt .post.
    that avoids standing there looking for pliers or wrench or fire extinguisher while entire car sends up smokesignals . .most folks these days dont know how to read smoke signals . . .so its a waste of time- use cell phone instead
    ...
    use marine grade tinned copper CABLES. and WIRE, for these tasks..
    check these connections on a regular maintanence schedule...
     
  11. dbswissy

    dbswissy Farmall Cub

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    There's a lot of wisdom here. Thanks all for your input!

    Those who posted blaming a short on main + line win this one. I was mostly wrong. I found that my main positive 1 gauge had been resting on my steering shaft and had worn a hole right through it. May not have been the worst place for a short to happen, but pretty bad! I'm just glad it didn't start a crazy fire!

    I replaced the ground with a 1 gauge (thanks, Jay) and got it securely connected to the engine. I also bought a grounding strap to run from the battery ground to the frame. Joe, let me tell you, my truck fires up like a rocket now! I've got WAY more cranking amps. I think the small ground wire running to the frame was barely enough to handle starting.

    So now, I have to deal with some of the side effects of this short. Mainly that my headlights keep shutting off on me while I'm driving. Then they'll come on again. My brake lights seem to work fine. I may have a loose wire somewhere. I'll be looking around inside the truck tomorrow.

    I agree, Jay, maybe my misfortune will remind the members here to check your wiring regularly. I know I don't get to spend as much time as I should on regular maintence and expect the beast to run right. Don't work like that. :punk:
     
  12. Jay Tabor

    Jay Tabor Banned

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    wire loom hangers can be had at any/ and all hardware stores, so you can isolate and route and hang the + cable from batt to starter. then it wont touch nothing.
    I slide my + cable into split wrap, and or a 5/8th" heater hose from batt to starter.
    that way more rubbing can occur before the magic genie appears with a puff of smoke!
    the lights going off could be the cb inside the light switch.
    maybe you don't have the wire harness plug snapped onto the light switch securely.
     

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