Charging system help
Thread Starter
Heel & Toe
Joined: Feb 2010
Posts: 16
Likes: 0
Charging system help
I posted a question earlier about putting in a Pioneer nav system. The main reason I was doing this was because the factory nav system was going crazy. It would open every time I went to shut off the engine, the screen is very dim....it starts up OK but then immediately goes dim. Sometimes the touch screen works, sometimes not...sometimes even the side buttons don't work. So, I noticed my interior lights flickering a little at idle. When I turn everything on (lights, AC, seat warmers, etc) while the engine is idleing and I check the voltage at the alternator as well as the reading on the dash driver info, it falls below 12 volts. It jumps around from 11.5 to 12.2. If I rev the engine to 1500 rpm, it goes up to the 13 volt area. Everything off and at idle it's around 12.6 to 13 and it goes up to 14 at 1500 rpm and everything off. I am wondering if that is normal readings or is it low for alternator output. Could it explain the wierdness on the nav. Even my exhaust flow control system is not working now. All fuses are ok. Thanks!
Team Owner
Joined: Mar 2008
Posts: 21,502
Likes: 461
From: Southern Utah
I would be surprised if that was it because the NAV should work fine when the car is turned off and the voltage is just battery voltage. But the output of the charging system does appear low and jumpy.
Le Mans Master
Joined: Feb 2007
Posts: 8,514
Likes: 235
From: Currently somewhere in IL,IN,KY,TN,MO,AR,MS,AL, or FL
Sounds like a bad cell in the battery to me. What is the voltage at the battery with everything turned off? Allow 15 minutes for everything to shut down. It should be above 12V. 10.5V is definitely a bad cell and the battery needs to be replaced.
If you are below 12V at idle and only 13V at 1500 RPM then your alternator isn't keeping up with the load.
If you are below 12V at idle and only 13V at 1500 RPM then your alternator isn't keeping up with the load.
Le Mans Master
Joined: Sep 2004
Posts: 5,116
Likes: 5
From: Livonia MI
Could be an intermittent battery cell, a possible bad diode or other alternator problem. Most better auto part's stores can diagnose your charging system, and load test the battery. If you have another battery availible, try swapping it out temporarely. These alternator's are pretty expensive, so maybe look to find a local re-build shop if that's the problem. I wouldn't feel to comfortable driving this car, until you get this fixed.
