Electrical completely dead! Please help?

[avatar28]

I was sitting in my car with the engine idling to keep the heat going. No warning lights were on and the car was running fine when it suddenly stalled. I tried to restart it and it cranked for about 4 seconds and then lost all electric power (everything, no lights, no chimes, nothing). I tried moving the battery cables and it doesn't make a difference so I'm doubtful it is them. Anywhere else I can check that might cause a total electric power loss to the vehicle.

I have problems with what I believe to be the camshaft position sensor and I had a bad battery. One thing that would happen with the old battery is that when cranking it it would just lose almost all electric for a moment and then resume cranking. I replaced the battery this morning (it was colder and that was all she wrote for it). It's been working fine all day (other than starting issues caused by the cam sensor) although I still had a couple of instances with it momentarily losing power when starting. Oh, I have a bad tstat so this is the first time I've had it to full normal operating temp in quite some time. Not sure if that's relevant.

 

[mrecoolgar]

Remove the battery cables.
Wire brush the cable ends and the battery posts.
Reinstall tightly with dielectric grease.

 

[avatar28]

Remove the battery cables.
Wire brush the cable ends and the battery posts.
Reinstall tightly with dielectric grease.

Would that cause it to stall out too if it lost the connection? Where do they connect to the rest of the car (it's dark so hard to see)?

 

[avatar28]

Okay, connected a jumper cable from the neg terminal to the bracket attached to the alternator (that should be a ground, not sure how good it is since it seemed pretty nasty) since that was suggested to check the ground wire. Didn't make any difference. I then connected the cables to the battery of our other car and got interior lights and was able to start the car. It continued to run after I disconnected the cables. I'm really confused now.

 

[TimboSHO]

There is a bad connection at the alternator, or in that wire to the rest of the vehicle. Disconnecting a battery while it is running will not cause it to shut off, so you can rule out battery or cables from the battery.

I don't recall where the positive cable goes from the alternator, other than to the rest of the car's electrical system to charge everything, but there is some part of that wire that is not making a great connection. Hook up a voltmeter to the battery and while the car is running, start wiggling stuff around until your voltage drops. You should be able to narrow it down from there....

 

[avatar28]

Thanks, possibly a bit more info. The car ran for a few minutes. I sat back in it to continue my work on the radio and turned the heat on full blast. A few seconds later the dash lights dimmed several times and then the car died and everything went off again. I jumped it off again and, again, it ran fine, interior light was full brightness and everything. This time around I made sure lights, blower and everything were all off to minimize the electrical load. It ran longer (I'm not sure exactly how long, I wasn't staying out there in the cold, but at least 10-15 minutes) before it died. I'm starting to think the problem is a failing alternator that isn't putting out enough current (or at least not for long enough) and is draining the battery until the engine stalls out. Looks like I'm going to have to figure out what I've done with my multimeter and go check the voltages.

 

[avatar28]

Update: battery tested good. Closer inspection of the terminals led me to replace one of them and cleaning the other with a wire brush especially thoroughly. Electrical is fine now.