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1983 W150 ignition/charging

Discussion in 'Repairs, Maintenance, Help' started by PCRMike, Feb 20, 2015.

  1. PCRMike

    PCRMike Well-Known Member

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    A friend of mine in Arkansas is working on a truck that I am trying to help him with by phone. here is the story. The battery went bad. They put a new one in, and learned at that point the alternator was pumping out around 16 volts! They replaced the "box on the firewall" (voltage regulator), but report there is slime coming from the "two boxes on the drivers side fender" next to the orange box. I am sure this used to be a lean burn truck, but there is no computer, so I can only assume it was converted. It has been over 5 years since I have messed with an old D series truck, so I am asking for help in knowing what to check next. They pulled the alternator and had it checked. The amp gauge does not work either (has not in the past). First, what to check next, and I think the "two boxes on the fender well" are the starter relay and horn relay,,,,,, IIRC. He replaced the voltage reg, and it still pushes 16 plus. Anything else he needs to check?
     
  2. ImperialCrown

    ImperialCrown Moderator
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    Check the alternator field wiring. If the return is pinched or shorted to ground, the alternator will run 'full-field' output. An internal alternator field short is also possible.
    If he unplugs the v/reg, does the voltage drop down? I have had aftermarket v/regs bad out of the box.
    A working ammeter is important. These were known for bad contacts at the instrument cluster 'foil and clip' connections at the ammeter studs on the backside of the cluster. The firewall (bulkhead) terminal connections were also known to go bad.
    You should see the needle deflect down about 1/8" when turning the headlamps on (with the engine off) or deflect up when first starting the truck. I have soldered these contacts before to make a good connection.
    If the truck has the electronic fuel feedback system with an O2 sensor in the exhaust and the fuel metering solenoid on the carburetor and someone has disabled the PCM, the truck will not run well.
    One of those boxes may be an EGR timer. He may want to get ahold of a factory service manual for the truck. It may pay for itself straightening these electrical issues out. An example:
    http://www.amazon.com/Dodge-Pickup-Ramcharger-Service-Repair/dp/B0007INB2E
     
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  3. Scrounge

    Scrounge Got parts?
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    I had an '84 D100 -- the ammeter never worked in it, either. I tried junkyard gauges, and each one worked for about a day or so, then quit. The battery ground has one cable going to the engine (I think it was mounted on the a/c bracket), and a thinner one connected to the body (near the radiator). The engine ground is for the engine, the body ground is for the interior accessories. The body ground kept disconnecting, but I didn't fully fix it until just before I sold the truck. You might make sure both of them are solidly connected.

    The "slime" was on my truck under those two boxes, too. No one could figure out what they were for, but they didn't seem to affect performance.

    IC's first suggestion, to check the alternator's wiring, should be the first examination made. A wire could fray, or might not be properly connected. Did you have the alternator checked at a parts store? Long ago, I owned a '69 Imperial that seemed to be a hybrid -- I eventually found out the hard way that it took front brake pads from a '68 Imperial, but an alternator from a '70 Imperial. Maybe someone installed the wrong alternator for the truck's application.
     
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  4. PCRMike

    PCRMike Well-Known Member

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    Thanks guys. I will pass this on. TheyHad The Alternator Checked At A rebuilder. I will recommend the checks above. Thanks guys.
     
  5. Scrounge

    Scrounge Got parts?
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    Forgot to mention, I also had the starter relay replaced on that truck. I forget whether it was on the firewall or the fender wall, but it wasn't one of those two boxes.
     
  6. tazdevil

    tazdevil Member

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    The ammeter does not require the body to be grounded to the engine. It floats above ground and is entirely in the charge circuit. The alternator outputting 16 volts appears to be healthy, since it has no load with the apparent open ammeter. Am I right, IC?
     
  7. dana44

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    The alternator itself, is is a single or two wire field? Although the alternator is putting out voltage, with the truck running, pull off a battery cable and ensure it is actually charging the battery and able to run off its output. If she dies, one of the two field wires used to power the lean burn (had a Ramcharger with this issue, which is why I am mentioning this, it was an '84, too). After messing with it a couple hours, the second field wire powers about a dozen sensors and then to the positive side of the coil otherwise it won't charge (and may try overcharging to make up for it). As usual, follow the wiring diagram and it will show up where it connects and gets power from. They only used the two field wire units a couple years, and yes, I think Lean Burn was the reason.
     
  8. ImperialCrown

    ImperialCrown Moderator
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    The ammeter isn't a load. It just basically measures a voltage drop across a shunt in either direction (charge or discharge).
    http://www.datwiki.net/page.php?id=497&find=ammeter shunt&searching=yes
    There is a high resistance somewhere in the indicator circuit. Poor connections in these vehicles were common problems.
    The overcharging issue is a separate problem. Check wiring first.
     
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  9. pt006

    pt006 Active Member

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    I've found the ammeter nuts to be a little loose on a few older Dodge trucks. Pull the neg. battery cable before doing any electrical work. Pulling the instrument panel out might be necessary.

    16 Volt alternator output is way too high. It could be as simple as a pinched field wire. Or not.
     
  10. Locodave

    Locodave Member

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    On my 84 250 truck I had probs with voltage regs. Overcharging, frying out. Check ohms for a good ground from the reg's case to the batterys neg post. I cleaned the engine to body ground connections.

    I wound up putting a seperate wire from the neg batt post to the regulater mounting bolt. Solved the problem.
     
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  11. Locodave

    Locodave Member

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    The boxes with the slime. Metal about the size of a card deck? 4 wires connector into it? Thats the ignition control. Voltage reg has 2 wires to it on the connector.

    Amp meter. One side of it in the wiring diagram shows a red wire traces back to the batterys pos post. Other side shows a black wire T's back on a black wire to the batterys red wire to the pos post. 3 red and one black at the junction. Test black wire to batterys pos post if a good connection. The other end of the T's black wire goes to a fusable link. And to the alts black wire. Orange one side and exits to dark blue next to the pink wire at the ignition switch.

    Alts black wire goes to ground. Light green goes to voltage reg. Red goes to voltage reg and other things on the circut. Left to right on the alt shows light green, red, black to ground. Another black going to amp gauge and fusable links.

    Figure #18 -> http://www.autozone.com/repairinfo/repairguide/repairGuideContent.jsp?pageId=0900c15280052c44

    Does the dizzy have one or two connectors? If it was a lean burn or not original. Ballast resister with the dual pick-up relay.
     

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