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Registered
Join Date: Jun 2002
Posts: 883
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alt light on bright, dim at high rpm
Started the car the other day after sitting a week and noticed the alternator light on. It's a Marchal generator/alternator, if I recall correct. At idle, light is on bright, at high RPM (2-3k and above), light is dim, almost out completely. Checked voltage at battery, 13.09 idle, 14.5 at high RPM. Same with lights on.
Reading posts, seems the negative diode could be open at high RPM but can also be shorted given symptom at idle. I don't believe it can be in both states. Has an external regulator, Marchal as well. It's a 76 Carrera 3.0. Any thoughts? Cleaning the main harness connector and the external regulator connector didn't change the symptom. Last edited by diy83sc; 06-03-2017 at 07:32 AM.. Reason: Added details. |
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06-03-2017, 07:15 AM
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76 911S Targa
Join Date: Oct 2010
Location: Idaho
Posts: 1,150
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You are probably due for a rebuild. If you do it proactively you may not be stranded as I was in the middle of Montana with an overheated alternator. My guess is that two of the diodes are making up for the third which has shorted. You will still have semi-normal charging....for a while.
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76 911S, 2.7, Bursch Thermal Reactor Replacements, Smog Pump Removed, Magnecors, Silicone Valve Cover Gaskets, 11 Blade Fan, Carrera Oil Cooler, Turbo Tie Rods. |
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06-03-2017, 07:44 AM
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Registered
Join Date: Oct 2006
Location: MYR S.C.
Posts: 17,321
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call an alt rebuild shop. see if they can test both out of the car and repair.
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86 930 94kmiles [_  _] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD88 BMW 325is 200K+ SOLD 03 BMW 330CI 220K:: [_ _] RUNNING: [__] NOT RUNNING:01 suburban 330K:: [_ _] RUNNING: [__] NOT RUNNING:RACE CAR:: sold |
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06-05-2017, 04:27 AM
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