Fuel gauge erratic ???
Thread Starter
Burning Brakes
Joined: Dec 2003
Posts: 1,004
Likes: 7
From: Adelaide South Australia
Fuel gauge erratic ???
I have just reassembled my dash and gauges, but have noticed the fuel gauge wanders all over the place.....
I have a new sender unit in the tank, and wires to sender are secure.
The fuel gauge needle fluctuates a lot with movement of the car... braking, accelleration, corners.... It has always done that, but not as much as it is now. Also, when I use my turn signals, the needle jumps back and forth (about 1/4 tank indication) in synch with the flasher cam.
One further clue to the problem is that when I turn engine off, the needle remains at the fuel tank level..... but if any electrical load is applied (such as depressing brake pedal) the needle swings way over against the stop - way past the full mark. As soon as ignition key is placed to ON, the needle restores to display fuel level....
Any auto-electric gurus out there that can help me determine what these symptons indicate?
I have a new sender unit in the tank, and wires to sender are secure.
The fuel gauge needle fluctuates a lot with movement of the car... braking, accelleration, corners.... It has always done that, but not as much as it is now. Also, when I use my turn signals, the needle jumps back and forth (about 1/4 tank indication) in synch with the flasher cam.
One further clue to the problem is that when I turn engine off, the needle remains at the fuel tank level..... but if any electrical load is applied (such as depressing brake pedal) the needle swings way over against the stop - way past the full mark. As soon as ignition key is placed to ON, the needle restores to display fuel level....
Any auto-electric gurus out there that can help me determine what these symptons indicate?
Thread Starter
Burning Brakes
Joined: Dec 2003
Posts: 1,004
Likes: 7
From: Adelaide South Australia
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Melting Slicks
Joined: May 2007
Posts: 3,246
Likes: 4
From: Bay Area CA
It's a simple circiut,, power from the gauge fuse to a main pigtail, splits to about 8 leads, onme of them is to the fuel gauge, which with the back wire wound resistor is about 90 ohms,, down to the connector to the rear harness, to the in of the sender, which is 90 ohms full, out of the sender to ground. what your discribing is a voltage fluctuation into the sender, a fuse gone high resistance can cause this,, or a problem in the wiring to the sender, could also be a short in the rear wiring harness,, does your rear curtosy light work?
May be a short between the gauge and the sender to the rear lights,
Last edited by RunningMan373; Jan 6, 2008 at 06:56 AM.
Thread Starter
Burning Brakes
Joined: Dec 2003
Posts: 1,004
Likes: 7
From: Adelaide South Australia
What rear courtesy light?
Its a convertible..... the only lights I have inside are in the footwells and the rear storage compartment.
I am not aware of any rear courtesy lights.
But I will check the fuse and ascertain the ground connection on the rear of the gauge. Thanks
Melting Slicks
Joined: May 2007
Posts: 3,246
Likes: 4
From: Bay Area CA
Rear courtesy light?
What rear courtesy light?
Its a convertible..... the only lights I have inside are in the footwells and the rear storage compartment.
I am not aware of any rear courtesy lights.
But I will check the fuse and ascertain the ground connection on the rear of the gauge. Thanks
What rear courtesy light?
Its a convertible..... the only lights I have inside are in the footwells and the rear storage compartment.
I am not aware of any rear courtesy lights.
But I will check the fuse and ascertain the ground connection on the rear of the gauge. Thanks
Team Owner
Joined: Oct 2004
Posts: 23,831
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From: Springfield MO
St. Jude Donor '07
Thread Starter
Burning Brakes
Joined: Dec 2003
Posts: 1,004
Likes: 7
From: Adelaide South Australia
Melting Slicks
Joined: May 2007
Posts: 3,246
Likes: 4
From: Bay Area CA
Question is, does your ammeter work. if not, you hooked the ammeter power up to the feul gauge and vice-versa.
the rear light in coups short out a good deal of the time shorting wires in the rear harness which also contains the rear lights and the feul sender wires. just my 2c,, something to look at,, but i'd check the ammeter, fuel gauge wiring, see if the ammeter works. w/o it running, turn on the lights, if the fuel gauge moves but the ammeter doesn't, ther's your proble, good luck,, Chris.
the rear light in coups short out a good deal of the time shorting wires in the rear harness which also contains the rear lights and the feul sender wires. just my 2c,, something to look at,, but i'd check the ammeter, fuel gauge wiring, see if the ammeter works. w/o it running, turn on the lights, if the fuel gauge moves but the ammeter doesn't, ther's your proble, good luck,, Chris.
Thread Starter
Burning Brakes
Joined: Dec 2003
Posts: 1,004
Likes: 7
From: Adelaide South Australia
Ammeter is working OK.....
I will have to pull out the gauge cluster and check the rear to ascertain the ground connection.....
I've got to calibrate my temp gauge also..... it is reading too low.
Not sure if I have the right sender unit, or just need to change cal resistor on rear of temp gauge.....
Just another couple of items on the " To DO" list.
I will have to pull out the gauge cluster and check the rear to ascertain the ground connection.....
I've got to calibrate my temp gauge also..... it is reading too low.
Not sure if I have the right sender unit, or just need to change cal resistor on rear of temp gauge.....
Just another couple of items on the " To DO" list.
