Gas Guage Fix

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kiltsup
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Joined: Tue Jun 08, 2010 1:37 pm
Location: Flower Mound, TX.

Gas Guage Fix

Post by kiltsup »

My port side fuel tank guage appears to be nonfunctional. I filled the tank up so I know the tank is in fact full, however the guage is not reading or registering the fuel level. What needs to be replaced if the guage is not working? The guage itself and I assume there is some sort of mechanism inside the tank that might need to be replaced as well?
Cheers,
Rob & Heather McGregor

Kilts Up!
Flower Mound, TX.
1980 F-32 Express : Twin Chrysler 318's
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ready123
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Post by ready123 »

3 things to look at... it can be any of these
1) the wiring, is there continuity from gauge to tank sender
2) does the gauge function when Voltage is applied.
3) does the sender vary the voltage output to the gauge... need to measure this at low and full tank.

part of 2) does the gauge move when ignition is turned on and off?

You might find it is the wires and connections.
If you have a Voltmeter you can check the above items.

The sender could also be stuck and so not showing full tank.

Start at the gauge easiest to check... apply 12V across it's terminals does it move?
Do you have Voltage from sender wire to ground when ignition is on?
Michael
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1987 President 43' Twin Lehman 225SP Turbo
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1978 F32 Sedan twin 318 Chry SOLD
Safe Cove Marina, Port Charlotte, FL
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g36
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Post by g36 »

my bet since i had this problem once. check the wire connection at the tank sending unit.
1997 CARVER 405
"the BLACK PEARL"

past fleet
1978 F32 SEDAN CHRYSLER 318's

current fleet
1997 seadoo gts
1997 yamaha wave venture
1985 sunbird 18 ft runabout
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sunfish
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Big D
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Post by Big D »

If the connections at the gauge and the sending unit look good including ground wire, try this:

- remove the sender wire from the sender at the tank (typically center post)
- jump it to ground.
- turn the key to the "ON" position

If you get a full sweep at the gauge ("FULL") without any flickering, your wiring and your gauge are good and you should suspect the sender.

I don't know the type of gauge you have, there are typically a couple of different resistance types. If you are handy with a meter, you can check the sender as follows before taking it out:

- Turn ignition off
- On a 240 ohm gauge and sender combo for example, with the sender wire still off, you should have pretty close to 0 resistance on a full tank from the sender wire to ground. Infinate resistance means an open circuit in the sender. Close to 240 ohms would be the reading on an empty tank.
She was a 1969 36 ft wooden beauty with big blue 440s that we'll miss forever.
And thanks to the gang, 2012 Trojan Boater Of The Year
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Big D
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Post by Big D »

CORRECTION: the resistance reading is taken at the sender from the sender post to ground, with the sender wire off, not from the sender wire to ground.
She was a 1969 36 ft wooden beauty with big blue 440s that we'll miss forever.
And thanks to the gang, 2012 Trojan Boater Of The Year
kiltsup
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Joined: Tue Jun 08, 2010 1:37 pm
Location: Flower Mound, TX.

Post by kiltsup »

Thanks!! Located this link as well.

http://www.downloadingfiles.co.uk/telef ... ystems.pdf
Cheers,
Rob & Heather McGregor

Kilts Up!
Flower Mound, TX.
1980 F-32 Express : Twin Chrysler 318's
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