Charging issue.... I think

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85glht

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Well, my Dart has an issue with keeping the battery charged up.

Symptom: with a fresh battery, car starts and idles good. After ten minutes the idle goes to crap (it just dies). Try re-starting the car and it turns over like the battery is weak. Jump the battery with my truck and it turns over fine and fires right up. So, one would think that the alternator is junk. Took the alternator off and had it tested. It is fine. It even shows 13.8 volts at the battery when the car is running.
Tried a different battery and the results are the same.
I have a one wire alternator in the car (powermaster unit). I also have an electric fan, an MSD ignition and a Holley black electric fuel pump. Those are the only three aftermarket devices in the car.
Car was fine for two seasons like this. All I did was remove the heads for a port job and now I can't fix this problem. Any suggestions??
 
Heads are grounded to the chassis and the battery, did you double check that? Clean the connections etc.
 
Heads are grounded to the chassis and the battery, did you double check that? Clean the connections etc.


I'll check and clean them again. Maybe one of them isn't clean enough. Thanks!!
 
Charge the battery if necessary, start and warm the car until warm, then bump up the idle to simulate "medium cruise" IE 40-50mph or so

Read the battery voltage. Should be 13.8--14.2, in no case below 13.5 or above 15

Start turning on accessories. Lights, heater, radio, jumper the fan if necessary to get it on, IE turn on every load in the car you can

Now measure the battery voltage, AND measure the voltage at the alternator output stud

Post the readings here

Are you running factory wiring, IE you still use the factory ammeter?

If the voltage at the battery goes low but remains fairly normal at the alternator, you have a voltage drop problem in the charging line, and your top suspects are the bulkhead connector and the ammeter

Read this MAD article on the pitfalls of the bulkhead connector, and in some cases, the ammeter:

http://www.madelectrical.com/electricaltech/amp-gauges.shtml

If the voltage drops at BOTH the battery and alternator, something is wrong with the alternator (one or more bad diodes) or the alternator is not large enough
OR THE BELT IS SLIPPING
 
I will try all that you posted..... I'm running a powermaster alternator. It goes directly to the battery. It does not go through the factory harness. It is just odd that it was fine for two seasons and then, problems.

I hope to have time this weekend to mess with the car..... Been working far and by the time I get home I'm wiped out..... Not a good time to try to figure out problems.


Thanks for all the replies guys, I'll let you know what I find out.
 
Ok, cleaned ALL the ground connections. It seems to have resolved the problem. I had it idling outside for a bit, checked the voltage at the battery, 14.2 was the result. I checked it at the alternator, it read 14.5. So I believe everything is o.k. Just to be sure, I turned the engine off and started it back up. It fired right away just like it used to.:cheers:

Thanks to everyone who posted their suggestions!!
 
I figured that was the problem, since on a fully charged battery it should run at least an hour on the battery charge alone unless the fan remains on all the time.
 
The fan does run all the time. I had a thermostat controller for it but it shorted out. Didn't want to run an on off switch so I got it wired to come on with the key. I know it isn't the best scenario but it works.
 
Not your original problem, but how about $29 for an adjustable fan controller w/ relay? Hayden 3651 on www.rockauto.com. Same PN is $45 at Summit. I just ordered 2 (slowly adding fans to all my cars). Hope I didn't deplete their stock. I ran across it when browsing for my 64 Valiant 225. It has a sensor that screws into a 1/8" NPT port instead of the in-fin sensors of other kits. Before this, I was looking for just a temp switch for a roll-my-own design, but ~$30 on ebay for a 190 F one.
 
Not your original problem, but how about $29 for an adjustable fan controller w/ relay? Hayden 3651 on www.rockauto.com. Same PN is $45 at Summit. I just ordered 2 (slowly adding fans to all my cars). Hope I didn't deplete their stock. I ran across it when browsing for my 64 Valiant 225. It has a sensor that screws into a 1/8" NPT port instead of the in-fin sensors of other kits. Before this, I was looking for just a temp switch for a roll-my-own design, but ~$30 on ebay for a 190 F one.


I may look into that. Thanks for the heads up!
 
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