John, the easiest way to check the sensor is to remove it from the tank, but
leave it electrically connected. Be sure to attach a clip lead in order to
ground it appropriately. Turn on the battery power. Avoid sparking.
Then, move the swing arm and watch your gauge. It should move through its
complete mechanical travel from Full to Empty.
You can also use an ohmmeter to measure the resistance of the variable
resistance element (the sensor is called a rheostat or potentiometer). Turn
off the battery when you do this, and disconnect the lead going into the
harness. Measure across the element using your ohmmeter. You will have to
research the resistance value of the sensor; perhaps someone on the
reflector knows the correct resistance value. I seem to recall 90 ohms. In
any case, as you swing the float arm, you will see the resistance value
change on your ohmmeter, from near zero to perhaps 90 ohms or so.
== Alex in Maine
"The Blue Mainie," 1960 Austin Healey 3000 BT7
"Conkling," 1946 M.G. TC #1321
Former owner 1957 A-H 100-6, 1967 A-H BJ8,
1965 MG Midget
http://home.roadrunner.com/~alexmm
----- Original Message -----
From: "John Snyder" <helyjohn at cablespeed.com>
To: "Healey List" <Healeys at autox.team.net>
Sent: Saturday, September 17, 2011 4:03 PM
Subject: [Healeys] Fuel Gauge
>I have a problem with the gas gauge or the gas level sensor in the tank in
>my
> BN7 MK2. The gauge reads Full all the time, no matter how much is in the
> tank
> unless I really stand on the accelerator, and then the gauge drops to 1/4
> and
> then comes back to full. The gauge was rebuilt by Mo-Ma in 2005, and the
> sensor has never been rebuilt or replaced. Is there an easy way to check
> the
> tank sensor? John Snyder, Port Townsend, WA
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