I had a new alternator and belt put in my car two weeks ago. My volts guage was running about 14 (halfway). Lately I noticed that with my headlamps on or the radio, that the volts would creep down all the way to 11! So I turned off the accessories and immediately it would creep back up to 12.

Yesterday my car just wouldn't start. It clicked and the volts was on 9. Went to autozone and got one of the 80 dollar good batteries and put it on. Started out at 14 again but it was trickling away again and so that night I tested the alternator by removing the negative battery cable with the car running. The car ran for 10 minutes so I figured it's not the alternator.

Today my car wouldn't start AGAIN. Volts on 9 and the starter just clicked quickly.



What the hell is wrong? Is it the alternator? I bought the alternator in New York and I'm in Texas now.

 

I had this problem with my formula (in december!) I replaced my alt, battery, and all heavy cables and terminals to no avail. I finally gave up and put my car in the shop. The problem turned out to be a circuit in the dash that supplies 12v to the stator of the alternator to excite it so the alternator will charge, without that 12v the alternator wouldn't do jack.. there was a bad trace on a circuit board that caused it to only happen sometimes. Once the circuit was bypassed (hooked up to an ignition switch activated circuit to supply volts to the alternator) everything was fine, and still is a year later.

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1987 Formula 350, headman hedders, Accel supercoil, cap, rotor.
MAF screens removed. 160 degree stat and manual fan switch.

Best ET: 14.745@91.317mph-Stock
Best ET: 14.418@95.51 mph-Modded
Ridiculed Founder of the Traction Impaired Crew