Lug_Nut
TDIClub Enthusiast, Pre-Forum Veteran Member
- Joined
- Jun 20, 1998
- Location
- Sterling, MA. USA
- TDI
- 2015 GSW 6M in S trim the other oil burners: 1967 two stroke Sonett 1988 Bolens DGT1700
Note to both preceeding posters:
The needle indicators can be repositioned on the gauge drive posts.
I drained my B4V by siphoning the last bit of fuel out through the tank-to-engine fuel port. I poured in 5 gallons of fuel from a jerry jug. I removed the needle from the fuel gauge and reinstalled it on the 4 gallon red indicator. That was my reserve. I then knew for certain that there was more fuel remaining, but not much more.
The speedometer and odometer get their pulses from the same sender, but are two independent meters. The odometer is a pulse count only, the speedo is a pulse over time indicator.
The discrepancy noted (one marked mile on the road equals one mile on the odometer, but doesn't equal one minute elapsed while the speedo indicates 60 mph) can be easily reduced or eliminated by moving the needle on the speedometer. My odometer is low by 8% with the snow tires presently in use. My speedo was low by closer to 12% with those tires. By moving the speedo needle to offset the difference between the two I have correlation. It looks a bit unusual to see the speedo at -4 mph when parked, but as soon as the car moves it jumps up to 0. Both are off by the same 8% when compared to the mile markers, but are equal to each other. A steady indicated 60 mph makes the odometer increase by one mile in 60 seconds. A steady 48 mph makes the odo increase by one in 75 seconds, 40 mph in 90 seconds. Since those three reference speeds are accurate, I've extrapolated that all the speeds I normally drive are accurate. I spend little time less than 40 (where a percentage error is but a few mph), or at greater than 75 (where a few mph difference would still mean a ticket), so I'm comfortable with a less than zero speed when parked.
Now a simple change of back to the shorter height summer tires will restore the odo and speedo accuracy relative to mile markers.
The needle indicators can be repositioned on the gauge drive posts.
I drained my B4V by siphoning the last bit of fuel out through the tank-to-engine fuel port. I poured in 5 gallons of fuel from a jerry jug. I removed the needle from the fuel gauge and reinstalled it on the 4 gallon red indicator. That was my reserve. I then knew for certain that there was more fuel remaining, but not much more.
The speedometer and odometer get their pulses from the same sender, but are two independent meters. The odometer is a pulse count only, the speedo is a pulse over time indicator.
The discrepancy noted (one marked mile on the road equals one mile on the odometer, but doesn't equal one minute elapsed while the speedo indicates 60 mph) can be easily reduced or eliminated by moving the needle on the speedometer. My odometer is low by 8% with the snow tires presently in use. My speedo was low by closer to 12% with those tires. By moving the speedo needle to offset the difference between the two I have correlation. It looks a bit unusual to see the speedo at -4 mph when parked, but as soon as the car moves it jumps up to 0. Both are off by the same 8% when compared to the mile markers, but are equal to each other. A steady indicated 60 mph makes the odometer increase by one mile in 60 seconds. A steady 48 mph makes the odo increase by one in 75 seconds, 40 mph in 90 seconds. Since those three reference speeds are accurate, I've extrapolated that all the speeds I normally drive are accurate. I spend little time less than 40 (where a percentage error is but a few mph), or at greater than 75 (where a few mph difference would still mean a ticket), so I'm comfortable with a less than zero speed when parked.
Now a simple change of back to the shorter height summer tires will restore the odo and speedo accuracy relative to mile markers.
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