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Registered
Join Date: Jan 2007
Location: connecticut
Posts: 1,093
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911 charging problem help with diagnosis
Hi, I have a 1986 911 and the charging is weak at about 13 volts or so on my hand held meter.Any way to determine if it is the alternator or the voltage regulator. Thank you.
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UnRegistered User
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Tons of stuff if you use the "search this forum" feature..
Here is a very recent one. Symptom/Solution – Bouncing/Floating/Off Tachometer and Random Bulb Burnout. Hope you find what you need...
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Bill K. "I started out with nothin and I still got most of it left...." 83 911 SC Guards Red (now gone) And I sold a bunch of parts I hadn't installed yet. |
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Registered
Join Date: Jan 2007
Location: connecticut
Posts: 1,093
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911 charging problem help with diagnosis
In my 1986 911 3.2 the question I have is. How to isolate the voltage regulator from the alternator.And to accurately determine which is not working properly.It is undercharging.Thank you.
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Registered
Join Date: Dec 1999
Location: Novato, CA
Posts: 4,740
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How old is your battery?
Reason: a bad or low battery will trick you into thinking your alternator or regulator is bad. Here's the scenario: you just spent the moolah on a new alternator along with a new regulator only to find out is still isn't charging right and now you just found out your battery was bad. Imagine how I stupid I felt when I did that! Last edited by stlrj; 01-08-2008 at 12:16 PM.. |
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Registered
Join Date: Oct 2005
Location: Birthplace of Bix
Posts: 1,145
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I agree with the 'check your battery' advice. I went through this with my 85 one year ago. Had the alt rebuilt even though it bench-tested OK, had a new VR installed, cleaned all the connections, grounds, etc., re-installed the group 49 monster battery, all for naught - the charging problem went away when I installed a red-top Optima.
Added bonus, now I don't have to check/clean out battery acid overflow in the front.
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Joe 85 Carrera 64 Honda Dream - for sale 71 Hodaka Super Rat - keeper |
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Registered
Join Date: Aug 2002
Location: Galivants Ferry, SC
Posts: 10,550
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STEP ONE ...... check standby voltage of battery.. car "off".
12.6 v = 100% charged 12.4V= 75% 12.2V= 50% 12.0V= 25% under 12V= essentially a dead battery...or close Yes..it drops off that fast as an indicator of charge/condition.
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Wil Ferch 85 Carrera ( gone, but not forgotten ) |
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Registered
Join Date: Jan 2007
Location: connecticut
Posts: 1,093
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911 charging problem diagnosis.
Thanks Guys,
I posted here to get ideas.I put a VR in my last 86 myself and wanted to be sure.I did remove the battery and charged it and it is weak.Thank you for all your help.I will post another question as to where is the best place to buy tires (I checked tire rack).And what is recommended/preferred brand for street use. Thanks again. |
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Registered
Join Date: May 2003
Location: Paris
Posts: 135
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Quote:
After a 2 months storage, I foud my batteries down (watch, alarm ...). I charged them with an Accumate (soft charging system) and they reached 13.6V without any problem after 3-4 days. When Accumate disconnected, the batteries stay around 12.5V When I started the 911, I mesured voltage and found it was moving from 14, 15 or 16 volts with no direct relation with the engine RPM. I changed the voltage regulator for a new one (901-603-206-02-M14) and when I started the car, the voltage is now perfectely stable but "only" 13.6V instead the usual 14.4/14.5 Volt Any idea ? |
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Registered
Join Date: Jan 2007
Location: connecticut
Posts: 1,093
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I am unsure.I would run a new thread and see if you can get advise.
Best wishes. |
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