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Registered
Join Date: Jul 2002
Location: Grove City, OH, USA
Posts: 26
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Speedometer and Odometer
Hello Again,
Well, I have been driving the car and verified via 2 different GPS units, that my speedometer is off by around 10%. It currently registers faster than the car is traveling. This also makes my odometer record an extra 10% in mileage. At 60 mph the speedometer registers 66, at 50 it registers 55, so on and so forth. After 10 miles via gps, it is 11 in the car. Also when I tested this the GPS units were both accurate to around 20 odd feet. Is there something simple that can be replaced? The tire pressure is spot on and the tires are the factory sizes. I can get my speedo calibrated for around 400 locally, but wonder if there is a less expensive piece along the line that can be replaced to fix it? Thanks in advance, Justin
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1986 951 Garnet Red Metallic |
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11-22-2003, 03:45 PM
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Autobahn Garage
Join Date: Jun 2003
Location: Ohio
Posts: 1,546
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Check the speed sensor in the transaxle. If you can swap it with another one and then do your testing again??? It will suprize you how different one is from the other
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T Tanner 76, 911s w/ Webers 76, 914/4 57, Speedster |
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11-22-2003, 04:25 PM
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Registered
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Are the rear tires stock size or larger?
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Hugh - So Cal 83 944 Driver Person NOT a 'real' Porsche -- Its Better!!!! When was the last time you changed your timing and balance belts and/or cam chain and tensioner? New Users please add your car's year and model to your signature line! Never break more than you fix! |
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11-22-2003, 05:18 PM
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Registered
Join Date: Sep 2003
Location: Littleton, CO
Posts: 161
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10%? I've seen worse. Mine was off 4% using the time-tested roadside mileage marker method. You can use your offset as an automatic speeding ticket fine reduction device. Kinda like a make-your-own plea bargin tool.
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'87 924S , sold. '99 Subaru O/B, 62K on first timing belt. Could have gone another 40K. |
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11-23-2003, 08:56 AM
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Ornery Bastard
Join Date: Sep 2001
Location: South Sound
Posts: 2,879
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Mine's off by a constant 10 mph over but the odometer reads fine. I bought the current speedo from someone who had gotten it re-built so I think that what happened is that the needle got put back on wrong when it was re-assembled. I need to get it fixed soon.
Aaron
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--------- Silver 1998 Volvo S70 T5 <- Daily (Anja) Guards Red 1986 951 <- Seattle car (Gretchen) White 1976 914 2.0 F.I. <- Prodigal car, traded away then brought back again (Lorelei) |
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11-23-2003, 11:01 AM
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vott does ziss do?
Join Date: May 2003
Location: Seattle
Posts: 6,676
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for liability issues in traffic court, German manufacturers' speedometers always read "optimistically"
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11-24-2003, 02:49 AM
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1983 Porsche 944 2.5 liter
