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Incorrigible
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Typical 944 voltmeter reading?
My car chucked it's old crappy A/C and alternator belt yesterday (I knew it needed to be replaced), and I limped home on battery, just made it. I have to say, the "Exclamation point!" warning light going on gets your attention immediately and sends your eyes darting around the gauges looking for why it came on, and the secondary lights for low oil pressure and alternator failure make that happen very quickly. Good system.
I replaced the belt last night ($14.99 at Autozone, a miracle). All is working correctly, but since that experience, I have been watching the voltmeter on the dash obsessively. It reads just a tiny hair over 12. Now, the truth is I am not sure where it ran before the failed belt. I thought more in the area of the low end of 13v? But, I know this: The alternator is putting something out - I accidentally disconnected the positive lead on the battery when I noticed it was loose, and the car kept running (I know, BAD to do, but it was an accident.) Everything works fine. My ammeter/multimeter took a dump, I should get a new one and check the actual output at the battery, I suppose. Would the belt being overtightened lower the alt output? Maybe I should just shut up and drive it and worry if the battery stops staying charged. Paranoia may destroy ya, as they say...  Jeff
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1988 951 all track modded and angry, 2002 Boxster '88 924S, '65 912/911, '86 951, '79 924, '85 944 N/A, automatic - all gone. "It makes me sad. Our cars were meant to be driven, not polished" - Ferry Porsche while surveying a concours field. |
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06-20-2012, 04:13 PM
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Proprietoristicly Refined
Join Date: Jul 2001
Location: ~Carefree Highway~
Posts: 5,833
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Typical car info:
Alternator & Charging System Checks (Alternator Testing) Mine is average with doors shut (interior lights off) at about 1200 RPM EDIT-is the AC compressor/clutch dragging? John
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1988 924S, 85,750K ..+ 1987 924S, 154K DD (+15K est. bad odo) Last edited by John_AZ; 06-20-2012 at 05:20 PM.. Reason: 1200 RPM |
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06-20-2012, 05:12 PM
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Incorrigible
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Thanks for the link, John. Good solid info.
I know all the common checks, but, like I said, no multimeter. If the compressor is dragging due to mechanical resistance, it would not show the low reading when the clutch was disengaged, I would guess. The clutch os electromagnetic, how much does that draw on the charging/ele trical system alone? What do most peoples' 944 dash voltmeters normally read? Jeff
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1988 951 all track modded and angry, 2002 Boxster '88 924S, '65 912/911, '86 951, '79 924, '85 944 N/A, automatic - all gone. "It makes me sad. Our cars were meant to be driven, not polished" - Ferry Porsche while surveying a concours field. |
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06-20-2012, 08:05 PM
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Proprietoristicly Refined
Join Date: Jul 2001
Location: ~Carefree Highway~
Posts: 5,833
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No voltmeter on my 924S.
Without a meter it is not possible to test. Reduce Warranties with Battery & Voltage Drop Tests | AIM GL John
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1988 924S, 85,750K ..+ 1987 924S, 154K DD (+15K est. bad odo) |
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06-20-2012, 09:50 PM
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Registered
Join Date: Nov 2005
Location: Northern VA
Posts: 13
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Mine also read low so I plugged one of those voltmeters into the cigg lighter
works quite well actually it showed little of 12 volts, compared it to one of my other ones, ( i have a few) and it showed closer to 13 or more so I did a little research and found that the alternators have voltage regulators with brushes on them that wear, easily replaced with access to alternator. So i replaced the regulator $25 for part and now it shows over 13 volts. So my recommendation is to try this first and it should improve your voltage.
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1997 Porsche Boxster Red 1993 Porsche 968 Red 1988 Porsche 944 Metallic Gray 1987 Porsche 924S Red 1987 Porsche 924S White |
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06-21-2012, 06:13 AM
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porscha
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I have 13.6volts @idle I find it low
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06-21-2012, 06:51 AM
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Registered
Join Date: Nov 2005
Location: Northern VA
Posts: 13
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That is actually good, anything over 13 at idle is good, it should be between
13.5 and 14.0 while driving along. Also turn on lights, a/c etc. and see if it stays about the same, if so you are good.
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1997 Porsche Boxster Red 1993 Porsche 968 Red 1988 Porsche 944 Metallic Gray 1987 Porsche 924S Red 1987 Porsche 924S White |
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06-21-2012, 11:53 AM
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Elsa
Elise
