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Registered
Join Date: Apr 2003
Location: miami fl
Posts: 124
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80 sc laternator problem
I have a 80 sc with an alternator problem I have been trying to correct. Some months ago I had the internal voltgage regulator go bad and with help from this board I took the alternator out , replaced the regulator, and then had an alternator shop check it out to make sure everything was ok before reinstalling it. It was fine for awhile but then I began to get a very faint red light on the dash after starting and running. I charged the battery and then reinstalled. Still have the faint light. Battery voltgage is 12.75 volts sitting in the driveway. When I run the engine at 2000 rpm the faaint light becomes a little more noticeable. Before removing the alternator again, am I missing something? Thanks for the help.
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05-23-2010, 09:00 AM
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Registered
Join Date: Oct 2000
Location: Centennial, CO, USA
Posts: 1,405
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Fan belt tension right? Less than a half inch deflection. Could be a bad VR but before you remove it again, make sure you have the belt tight. YMMV
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Bill '72 911T-2.4S MFI Vintage Racer(heart out), '80 911SC Weissach,'95.5 S6 Avant Wunderwagen & 2005 997 C2S new ride. |
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05-23-2010, 11:06 AM
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Join Date: Jun 2009
Location: Manhattan Beach, California. Factory Delivery-Original owner-Retired engineer
Posts: 5,238
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Quote:
Did you put the shims back as they were? Also, What is your battery voltage with the engine running? It should be 13.5-14.5V A bad VR normally increases the above numbers, and eventually cooks the battery. Loose connection at the alternator? Bad re-build? Good luck, Gerry
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1986 911 Targa. Per Road and Track magazine: Only in L.A.: In the window of a bar in Hermosa Beach, California. "Happy Hour prices during all car chases." Last edited by 86 911 Targa; 05-24-2010 at 03:57 PM.. |
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05-23-2010, 01:18 PM
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Join Date: Jul 2009
Posts: 285
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you need to measure the voltage both at idle and running.
If youre getting erratic voltage, too low, then high, etc, probably the VR. If you're getting only 12.75 with no fluctuation, alternator is bad. |
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05-23-2010, 07:10 PM
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I have had this symtom happen to me, where the red light would appear & get brighter with more rpm.
It was none other than the VR. Somethin failed within its internal diode or somethin like that. (sadly, not all new components are 100%) |
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05-23-2010, 08:35 PM
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520i
1982 Porsche 911sc
