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Join Date: Oct 2003
Location: Miami
Posts: 905
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Alternator Light
My alternator light is staying on from idle to about 2500 RPM intermittently. Time to replace or anything to check first? It’s an SC engine.
I’m somewhat handy, is this difficult to do? |
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Join Date: Jan 2003
Location: Burford, ON, Canada
Posts: 2,319
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Well, it is not the alternator light that is at fault; it is reporting a problem with the charging system. The alternator and/or regulator may be faulty. Other possibilities include wiring and battery.
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Keeper of 356, 911, 912 & 914 databases; source for Kardex and CoA-type reports; email for info Researching 356, 911, 912 & 914 Paint codes, Engine #'s and Transmission #'s Addicted since 1975 |
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Yes I meant replace the alternator. Is there a test to see if it’s the alternator or regulator or are they one unit?
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Get off my lawn!
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Quote:
It can be either on a car that is 40+ years old. Please state the year of the car, and is the engine original, or a swap. More details on the vehicle will help in an accurate diagnosis.
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Glen 49 Year member of the Porsche Club of America 1985 911 Carrera; 2017 Macan 1986 El Camino with Fuel Injected 350 Crate Engine My Motto: I will never be too old to have a happy childhood! |
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Join Date: Oct 2005
Location: Northern California
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Can be a loose belt
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Mike PCA Golden Gate Region Porsche Racing Club #4 BMWCCA NASA |
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ROW '78 911 Targa
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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. |
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Quote:
As Mahler9th stated, it could be a loose belt, so start with that. If good, then check the VR if external. Jason
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'79 911SC Targa |
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My car is a 1977 Euro 911. It has a 10 year old rebuilt 3.0 SC in it.
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ROW '78 911 Targa
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What year SC engine?
Do you have an internal or external voltage regulator? (look beside the CDI for an external one)
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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. |
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What kind of voltage are you getting at the battery? OFF, idle and revved.
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Location: Miami
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Internal VR
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Join Date: Jan 2007
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Loose belt, regulator or worn brushes are the most common culprits. If it is only on at startup until your first higher rev, that is normal. With worn brushes the light ends to flicker a lot. With a loose belt, the light tends to glow dull under electrical load.
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Alternator light came on and stayed on my '76, replaced regulator before taking alt off, fixed it.
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So my light on is intermittent, goes off above 2500 RPM, anyone vote to replace the brushes or is that a PITA to do as well? Replacing the alternator is about $800.
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Quote:
An alternative to buying a new one would be to have yours re-built. Get a recommendation for a local shop that does that work, you could save a lot of $. Jason
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'79 911SC Targa |
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since the VR is triggered by the alt lamp, is the correct lamp in the gauge?
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Join Date: Feb 2013
Location: Winnipeg, Manitoba
Posts: 415
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Get one of those cigarette lighter volt meters. I got one off of eBay. It helped to know the voltage with my charging problem.
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1988 Carrera coupe 1966 250 Ducati 2015 VW Golf TDI gone because Dieselgate! 2021 VW Golf TSI 2014 Ninja 300 |
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