I got a really bad surprise today

Wildaugust said:
Man that sucks, you go out for a cruise and come home on a tow truck! I'm glad it didn't cause you anymore damage. I'm not 100% sure but, I think that fuse link protected power wire goes to the big terminal on the starter relay. You said smoke came through the dash vents? I think you must have had a dead short somewhere. I would have a good look under the dash, especially the wires to the amp gauge and the gauge itself. Maybe with the battery disconnected and everything in the car turned "off", connect an ohmmeter lead to the main power wire and the other lead to ground to see if you have a short in the car's wiring. You might get a reading but it shouldn't be zero, if it's 0 ohms you have a short. An infinite reading (no reading) should be OK too. IDK if a Mopar could do this but I've had Fords do it. The VR fails and allows full battery voltage to short through the alternator's rotor (field) windings causing the wiring harness, battery and alternator to become very warm (hot) to the touch. IMO that would be enough to take out the fuse link. Also possibly, but I think unlikely, bad diodes in the alternator could cause this. It would be a dead short to ground from the battery through the fuse link, ammeter wiring and alternator (if Mopar charging systems work similar to Ford charging systems). I've been lucky so far as I haven't had to troubleshoot my Newport's charging system yet. Anyway, I hope you find the problem and that it won't be anything too bad.
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Yeah, the motor shut off and then I notices a few whiffs of white smoke come from one of the vents....although I can't be 100% certain I'm thinking it was the fuse/wire sheathing/plastic connectors melting. I didn't notice anything abnormal when I looked under and through the dashboard, but I think I'll get up under there again with a good flash light to be sure..........more to come.
 
Is it possible that the starter solenoid is drawing a constant load and over heating the link?
 
7mag said:
Is it possible that the starter solenoid is drawing a constant load and over heating the link?
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It is a remote possibility, however I've never noticed / saw any signs of melting or flashburns on the wire itself. I'm under the hood at least once or twice a week doing other stuff and never noticed anything abnormal with the batt cable or the link itself, BUT it could have happened.

The battery is undamaged. I jury rig the wire back together without the fused link, and it get's hot, I guess that will tell me.
 
My coolant leak problem is fixed. I borrowed the cooling system pressure tester from AAP. It held 16psi for an hour. No leaks! Whew! It was the new radiator cap. I put the 34 year old cap back on it and took for a run on I-95. Problem solved.
 
OK, I've had another cup of coffee. LOL. The wire that was protected by the fuse link basically connects the battery to the alternator. It is the main power wire to the whole car too. The circuit goes through the bulkhead connector to the AMP gauge and then through the bulkhead connector again to the alternator's output terminal. If no other fuses are blown, it would probably mean that the short occured in a major circuit that isn't protected by a fuse or before the fuse box. That could be the charging circuit itself, maybe the headlight circuit before the headlight switch,etc. Instead of just using a jumper wire which you said gets warm, I would connect a 12 volt test light in series with the main power wire. Then unplug things one at a time until the light goes out. That way you aren't causing a dead short and risking damage to anything else. I would still suggest checking the VR too to see if it is shorting through the alternator.
 
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It's scary to have that happen. Back in the mid-90s I had my favorite shop replace the starter solenoid on my '64 Skylark. I picked the car up after work, put the top down, and drove home. I was sitting at a red light with the radio playing when all of a sudden the engine quits and the radio too. As I try to restart the car - with nary a click - I notice white smoke coming out from under the hood. I jump out, pop the hood, and this huge cloud of acrid white smoke spews out. At that instant I pretty much hoped that if it burned, that the whole thing would go up in flames.

Eventually the smoke cleared and there was no fire. I was able to see that the positive battery cable had melted from a dead short. I was able to get hold of the garage and they sent a tow truck. Turned out that when they did the solenoid, they had disconnected the battery cable and when they reconnected it, it got rerouted and was touching the exhaust manifold. Car got hot, the manifold melted the insulation off the cable, bare cable dead shorted to ground. Fortunately they were able to repair everything they caused and the damage didn't seem too extensive. Scary as hell at that moment though.
 
70FuselageImperial said:
It is a remote possibility, however I've never noticed / saw any signs of melting or flashburns on the wire itself. I'm under the hood at least once or twice a week doing other stuff and never noticed anything abnormal with the batt cable or the link itself, BUT it could have happened.

The battery is undamaged. I jury rig the wire back together without the fused link, and it get's hot, I guess that will tell me.
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Check your starter for a bad windings in the armature,I had this happen once years ago in my old `71 Imp. New starter and a butt connector. FIXED!
 
Hey just wanted to add. Get that amp gauge converted to a voltmeter ASAP. Every old Mopar I've owned I've had Redline Gauge Works convert my factory amp to a voltmeter and have them install their solid IVR as well for an extra $30 or get one from RTE (Real Time Engineering). I mention this because sometimes the amp gauge can cause issues like this as well especially if it is on it's way out. In older dodge truck especially ones from the mid 70s the amp gauge gets so hot that it has melted the gauge. There is other ways to do it I just have Redline convert to the voltmeter and tie the wires together bypassing the amp gauge. Seems to work fine in this case. It cost $160-170 to convert plus they calibrate your gauges from what I remember.
 
THANKS for all the useful info and tips guys. This morning I'm gonna grab my multimeter, tool chest and get started on trying to figure out just what the heck happened to her....hopefully this won't turn into an unending mystery. I'll post as I go, maybe something interesting will come out of this.....
 
Here's where I'm at so far, one suggestion made was to check the bulkhead connectors for any burn marks/flashes....aside from a bit of dirt they look ok...no burns...blades look nice, all of it looks like it was just connected for the first time yesterday...

BULK01.jpg


IMG_6854.jpg


IMG_6851.jpg


IMG_6848.jpg
 
1978 NYB said:
Good luck! I hope it's a simple fix for you.
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Lol, me too!! I want to replace the entire pos cable rather than splice in a new fusible link (yes, that was suggested to me)...but I'm not sure I'll be able to do that now as the fusible link wire combines with another cable trunk (part of which continues and splits on to the bulkhead connector.

BATTCAB03.jpg
 
So, whats up?

Wow, that's great advice from commando. All that juice running to the pos gauge is CRAZY.
 
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