1974 Plymouth Duster Electrical problems when hot

[Juan Fuentes]

Hey Guys, I have a 1974 Plymouth Duster with a 318 and 904 Automatic Transmission. I acquired it in February and have been getting it road worthy since. Yesterday I went for a 'shake down' on the car before taking it to get the car inspected and while accelerating and got to about 30 MPH the car just died on me. I pulled over and tried to crank but the battery was completely dead. I waited about 10-15 Mins and then the engine cranked over and started (the cranking was slower than usual). I was limping it back home and not pressing on the gas much just letting it coast but it would still die and I would have to wait again to try and crank. The temperature was reading at 180 during this time. When I finally got it back home, I let the car sit for 30 mins and while cranking I was checking the battery and it was dropping to 6-7 Volts. Also the positive battery cable was super hot. All wiring is original and the distributor is electronic not points. If anyone has experience with this issue or can help in anyway, it would be greatly appreciated!
P.S I did not see a ground strap from engine to frame or on the heater box so I will try there

 

[Car Nut]

 

[MV8]

From what I can't see (no pics) and assuming you had already disconnected and wire brushed/cleaned electrical connections everywhere and replaced any damaged wiring as part of getting it road worthy, It sounds like it isn't charging, the battery is probably good, and the starter is probably bad.

 

[67Dart273]

There's a lot of different things that could be wrong and yet several possibilities might be really simple

MV8 already mentioned a couple How old is the battery? What is your "feel" for it's condition?

Do you have a factory service manual. If you send me a PM (conversation) I can help you with that for nothing more than some postage.

So Old battery? Battery fully charged? Battery defective? Dirty posts/ clamps? CLEAN then, don't just guess. Check the starter where the main cables bolt on are they tight? Battery main ground should go to ENGINE block.

Charging when operating? Do you still have an operating ammeter? It should be in mid point in normal operation after battery charges up normal. Turning on headlamps with engine stopped should move to left of center showing discharge. After starting engine, ammeter should register to right of center until battery comes up on full charge.

Other issues when hot is starter may be suffering from "heat soak." Normally a good healthy starter won't give trouble. A modern "mini" starter (like off a 90's 5.2 or 5.9 RAM or Dakota draws way less battery current than the big old original starters.