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Registered
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Volt Meter reading - what should it be?
My Volt Meter is always reading @ 12. Is that high, low, or just right. I can't find the base readout in any manual.
I had to change my battery yesterday, but first it was several years old, and secondly because I think my interior lights stayed on - the door/hatch switch to turn them off seemed to fail. Anyone know what my meter should read? |
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turbo S
Join Date: Mar 2009
Posts: 57
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I assume you mean the meter in the dash. Mine also reads 12, but the alternator should be putting out about 14.4 when running. Needless to say I tested the car with it running and sure enough the gage in dash was reading 12v=14.2 for the car in reality.
You should test this on your car. Simply let the car idle and check the voltage at the battery with a volt meter. If it is a little low just rev it up to 2500 rpm, you will have max output from the alternator by then. My guess is you just have a lazy gage like mine, hey for 20+ years old it can be a little lazy ![]() |
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Registered
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14 is normal. You cant trust the instrument gauge though. The needle can just move wherever it wants, you can rotate it with a finger.
My dash was reading off when i tested manually. When I had the instrument panel off, I just bumped the needle a bit so now it reads 14 lol |
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In the Fires of Hell.....
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If you clean your grounds, especially those at the rear of the engine and on the bell housing, you will probably get a higher reading on your gauge. I know I did.
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PCA Instructor: '88 951S - with LBE, Guru chips, 3Bar FPR, 1.3mm shimmed WG, 3120 lbs, 256 RWHP, 15 psig boost |
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That Guy
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Ground cleaning fixed my jumping gauges. I eventually replaced all of the battery cables on the car and the voltage gauge now goes to 14v and just about everything works better now..
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Jon 1988 Granite Green 911 3.4L 2005 Arctic Silver 996 GT3 Past worth mentioning - 1987 924S, 1987 944, 1988 944T with 5.7L LS1 |
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Registered
Join Date: Dec 2008
Location: TEXAS
Posts: 172
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techno duck
what did you mean exactly by everything works better? im asking to see what is overally affected by the bad grounds. My car reads 12v now but alternative etc is OK, had all checked out by shop thanks
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- 1988 Porsche 944 Turbo S Silver Rose - 1983 Porsche 944 V8 with SBC 350 (400hp dyno) - 1988 BMW M5 |
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Registered
Join Date: Jun 2003
Location: Phoenix, AZ
Posts: 1,327
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upper 13's to low 14's at operating temp.
the gages are innaccurate unless calibrated. when the case is split, there's a small calibration screw on the side of the vm. in/out a time or to get it in sync with a decent vm.
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87 951, K27/6, Almond Beige, 17" Turbotwist 87 944S, alpine white, 5sp died a violent death 84 944, silver/brown, auto, gone but not forgotten "may the force be with you" Last edited by bearone2; 06-21-2009 at 06:36 AM.. |
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That Guy
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Quote:
My car used to read right around the midway mark (13v) on the gauge. After replacing everything including the voltage regulator it goes to 14v on a cold start and will slowly work down to about 13.5v as the car warms up. I agree with bearone though that the dash voltmeter is off, in my estimates by about 1v from what you are actually putting out. Best way to check is to see what you are getting at the battery with the car running and compare it.
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Jon 1988 Granite Green 911 3.4L 2005 Arctic Silver 996 GT3 Past worth mentioning - 1987 924S, 1987 944, 1988 944T with 5.7L LS1 Last edited by Techno Duck; 06-21-2009 at 08:04 AM.. |
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your average wrencher...
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i just got done doing my cluster swap and now everything reads what it should one mine, i cleaned all the power and grounds on the back of the cluster itself and now no more jumpy fuel gauge. it even reads completely filled up (4/4)
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1982 931 *project* 1986 951 Garrett turbo, Rogue Tuned (sold ![]() 1987 944S chipped, konis, rollbar (traded) 1979 924 total rebuild and blueprinted (sold) |
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