Fuel Gauge/Sending Unit Question
08-26-2010, 10:31 AM
#1
Instructor
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Fuel Gauge/Sending Unit Question
Okay,
I have searched the forum for an answer....but I can't seem to find one.
1988 928 S4.
My Fuel Gauge reads full at all times. When I unplug the connection for the Sending Unit should the needle drop to empty? Mine STILL shows full.
Is there a short somewhere? Do I need to pull a fuse to "reset" the gauge?
I have a replacement Sending Unit that I plugged into the connection making sure the float was at the bottom.....STILL shows full.
Any clue?
I have searched the forum for an answer....but I can't seem to find one.
1988 928 S4.
My Fuel Gauge reads full at all times. When I unplug the connection for the Sending Unit should the needle drop to empty? Mine STILL shows full.
Is there a short somewhere? Do I need to pull a fuse to "reset" the gauge?
I have a replacement Sending Unit that I plugged into the connection making sure the float was at the bottom.....STILL shows full.
Any clue?
08-26-2010, 10:48 AM
#2
Three Wheelin'
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Sounds like somthing in the cluster itself is bad... although it could be something along the way.
One check that might be interesting would be to take a multimeter and measure from ground to each of the pins of the sender connection (sender disconnected and igntion on). IIRC, two should be 0V, and the other should be about 5.5V. Let us know what you find on yours.
One check that might be interesting would be to take a multimeter and measure from ground to each of the pins of the sender connection (sender disconnected and igntion on). IIRC, two should be 0V, and the other should be about 5.5V. Let us know what you find on yours.
08-26-2010, 02:11 PM
#3
Drifting
read through this thread
http://forums.pelicanparts.com/porsc...ght=Fuel+Gauge
Page 2 go's into how to test your gauge with a Ohm meter and so forth
http://forums.pelicanparts.com/porsc...ght=Fuel+Gauge
Page 2 go's into how to test your gauge with a Ohm meter and so forth
08-26-2010, 03:24 PM
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I have an '88 S4 and I just replaced the sender unit in the tank. It wasnt reading correctly. New sender part cost $130 online (did some shopping around) and took all of 15 minutes to swap out. Easy job.
Joe
Joe
08-26-2010, 08:23 PM
#7
Team Owner
when you reinstall the sender to the tank soak the securing nut in very hot water for 5 mins then install it.
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08-29-2010, 02:01 PM
#8
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I'll get a volt meter and see what I come up with.
08-29-2010, 04:59 PM
#9
Racer
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Hi blaydrunner,
I would be careful about messing around with the sender with the power on in the car.
My understanding is the fuel sender is a variable resistor, IE the resistance changes as the float goes up and down a thin wire.
I never tested the sender by disconnecting it, using an ohm meter, etc., as it did read, but would read incorrectly after the tank went below a 1/4 full.
I didnt want to "fiddle around" trying to clean the sender's fine wire, just bought the replacement and everything has worked fine since I installed it.
VTY,
Joe
I would be careful about messing around with the sender with the power on in the car.
My understanding is the fuel sender is a variable resistor, IE the resistance changes as the float goes up and down a thin wire.
I never tested the sender by disconnecting it, using an ohm meter, etc., as it did read, but would read incorrectly after the tank went below a 1/4 full.
I didnt want to "fiddle around" trying to clean the sender's fine wire, just bought the replacement and everything has worked fine since I installed it.
VTY,
Joe