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timmy2 timmy2 is online now
ROW '78 911 Targa
 
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Join Date: Jul 2011
Location: Salem, OR
Posts: 10,217
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The tachometer jumping sounds like the classic symptoms of the VR or Alt starting to fail.
Use a voltmeter to check your voltage when car is turned off, then at idle, then at 2000 and 3000 rpms.
Should be above 13.2 volts when running. If it is below that then you need to have them tested.
From the description of the fan belt squealing, I would check tension of the belt first.
If the belt is good and the output voltage is low or fluctuating, then it's probably time to pull your Alternator and have it tested professionally.

Steps:
1. Adjust belt tension
2. take voltage measurements
3. either keep on driving if belt tension was the problem or pull alternator and have it repaired.

(Not sure if your car has seperate VR or internal)
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Dennis
Euro 1978 SC Targa, SSI's, Dansk 2/1, PMO ITBs, Electric A/C
Need a New Wiring Harness? PM or e-mail me. Search for "harnesses" in the classifieds.
Old 09-21-2012, 10:03 AM
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