Electrical charging system question, Alternator? |
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Electrical charging system question, Alternator? |
rjames |
Jun 10 2006, 04:11 PM
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#1
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I'm made of metal Group: Members Posts: 3,974 Joined: 24-July 05 From: Shoreline, WA Member No.: 4,467 Region Association: Pacific Northwest |
I installed a brand new battery and a new voltage regulater last week in the car. My volt meter is showing 12.5 volts at the terminals. With the car running and the lights and fan on my volt meter fluctuates between 12.7 and 12.9, then slowly starts to dip, getting as low as 12.5 before I decided to shut the engine off because I could see that the battery was slowly draining.
Would it be logical that the alternator might need replacing? The alt. belt also seemed tight (not sure exactly how tight it should feel though.) I can check the electrical connections (have to find them first though.) The connections at the battery all look good though. It doesn't look like a fun job to replace the alternator, but I'm up for the challenge. Anything else I should look for before I go this route?? Thanks! PS: Forgot to add that the alternator light on the dash comes on when starting the car, but goes off right away once it's started and doesn't come back on at all when driving. |
rjames |
Jun 24 2006, 08:51 PM
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#2
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I'm made of metal Group: Members Posts: 3,974 Joined: 24-July 05 From: Shoreline, WA Member No.: 4,467 Region Association: Pacific Northwest |
QUOTE Do the test like this: 1. Put a DVOM on the battery posts. 2. Remove the voltage regulator from the relay board. 3. Start the 914. 4. Using a jumper wire, connect the D+ and DF contacts. 5. You should see 16 volts or so on the DVOM. If you do, your alternator is good Did the test, and it showed 16+ volts. Hmm... so after doing this test I plug the voltage regulator back in, drive around a bit and what-do-ya-know, it's showing 13.3 at Idle. Nice. The next day, I drive around and I'm back to showing 12.5 or so at idle, and when the car is off the battery is reading 12.3ish. The one thing I haven't checked for is when it's idling at 12.3 or whatever, to short the D+ and DF contacts to see if the alternator kicks right in. Although, my guess is that it will. So I'm back to my original question- is it possible for the alternator to work correctly sometimes, and other times not? Can both of my relaby boards be causing problems? Could both my voltage regulators? Is it worth it at ths point to check the alt bulb in the dash to make sure it's the correct one? Are these still available new? |
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