Fuel gauge problem?
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Joined: Apr 2009
Posts: 14,333
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From: Stanley, VA
At the sending unit, unplug the wire and ground the one that goes to the gauge. With the ignition "on" the gauge should swing all the way to full. If it does, either the sender is bad or the ground is bad.
One other possibility is the float has a crack and is fuel logged (sunk). The floats are available separatley.
One other possibility is the float has a crack and is fuel logged (sunk). The floats are available separatley.
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At the sending unit, unplug the wire and ground the one that goes to the gauge. With the ignition "on" the gauge should swing all the way to full. If it does, either the sender is bad or the ground is bad.
One other possibility is the float has a crack and is fuel logged (sunk). The floats are available separatley.
One other possibility is the float has a crack and is fuel logged (sunk). The floats are available separatley.
Hotshot
Joined: Apr 2009
Posts: 14,333
Likes: 247
From: Stanley, VA
No, you don't ground the sending unit itself.
There are two wires that go to the sending unit. One is a short wire that is a ground. It is screwed to the crossmember in front of the tank. The other wire is the wire that goes to gauge. Unplug the wiring harness at the sending unit. Find a good CLEAN section of the frame. Take the wire that goes to the gauge and ground it to the frame. With the ignition in the "on" position the gauge should swing over to full.
You don't need to drop the tank to do this test, just unplug the wiring harness.
The first picture is the sending unit wiring harness, this gets unplugged from the tank.
The second picture shows the front of the tank with the plug and sending unit.
There are two wires that go to the sending unit. One is a short wire that is a ground. It is screwed to the crossmember in front of the tank. The other wire is the wire that goes to gauge. Unplug the wiring harness at the sending unit. Find a good CLEAN section of the frame. Take the wire that goes to the gauge and ground it to the frame. With the ignition in the "on" position the gauge should swing over to full.
You don't need to drop the tank to do this test, just unplug the wiring harness.
The first picture is the sending unit wiring harness, this gets unplugged from the tank.
The second picture shows the front of the tank with the plug and sending unit.
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No, you don't ground the sending unit itself.
There are two wires that go to the sending unit. One is a short wire that is a ground. It is screwed to the crossmember in front of the tank. The other wire is the wire that goes to gauge. Unplug the wiring harness at the sending unit. Find a good CLEAN section of the frame. Take the wire that goes to the gauge and ground it to the frame. With the ignition in the "on" position the gauge should swing over to full.
You don't need to drop the tank to do this test, just unplug the wiring harness.
The first picture is the sending unit wiring harness, this gets unplugged from the tank.
The second picture shows the front of the tank with the plug and sending unit.
There are two wires that go to the sending unit. One is a short wire that is a ground. It is screwed to the crossmember in front of the tank. The other wire is the wire that goes to gauge. Unplug the wiring harness at the sending unit. Find a good CLEAN section of the frame. Take the wire that goes to the gauge and ground it to the frame. With the ignition in the "on" position the gauge should swing over to full.
You don't need to drop the tank to do this test, just unplug the wiring harness.
The first picture is the sending unit wiring harness, this gets unplugged from the tank.
The second picture shows the front of the tank with the plug and sending unit.
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Hotshot
Joined: Apr 2009
Posts: 14,333
Likes: 247
From: Stanley, VA
This will tell you whether the problem is the sending unit or there is a gauge/wiring problem.
If you ground the wire and the needle swings over, everything to the point where you grounded it is good. That means either the sending unit is bad or the ground connection at the crossmember is bad and needs to be cleaned. One other possibilty, like I said above, is a cracked float. This is a common problem. The float is brass and can develop cracks or the solder joint on it can also crack allowing the float to fill with fuel and sink to the bottom of the tank, making the tank always read "empty".
If the gauge doesn't swing to full, then the problem is either the gauge itself, the wiring from the gauge to the sender or the power to the gauge.
If you ground the wire and the needle swings over, everything to the point where you grounded it is good. That means either the sending unit is bad or the ground connection at the crossmember is bad and needs to be cleaned. One other possibilty, like I said above, is a cracked float. This is a common problem. The float is brass and can develop cracks or the solder joint on it can also crack allowing the float to fill with fuel and sink to the bottom of the tank, making the tank always read "empty".
If the gauge doesn't swing to full, then the problem is either the gauge itself, the wiring from the gauge to the sender or the power to the gauge.
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Senior User
Joined: Jul 2011
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No, you don't ground the sending unit itself.
There are two wires that go to the sending unit. One is a short wire that is a ground. It is screwed to the crossmember in front of the tank. The other wire is the wire that goes to gauge. Unplug the wiring harness at the sending unit. Find a good CLEAN section of the frame. Take the wire that goes to the gauge and ground it to the frame. With the ignition in the "on" position the gauge should swing over to full.
You don't need to drop the tank to do this test, just unplug the wiring harness.
The first picture is the sending unit wiring harness, this gets unplugged from the tank.
The second picture shows the front of the tank with the plug and sending unit.
There are two wires that go to the sending unit. One is a short wire that is a ground. It is screwed to the crossmember in front of the tank. The other wire is the wire that goes to gauge. Unplug the wiring harness at the sending unit. Find a good CLEAN section of the frame. Take the wire that goes to the gauge and ground it to the frame. With the ignition in the "on" position the gauge should swing over to full.
You don't need to drop the tank to do this test, just unplug the wiring harness.
The first picture is the sending unit wiring harness, this gets unplugged from the tank.
The second picture shows the front of the tank with the plug and sending unit.
do i just hold it down to the frame while someone checks the gauge move?
Hotshot
Joined: Apr 2009
Posts: 14,333
Likes: 247
From: Stanley, VA
Yes. The socket in the wiring harness is a female so you'll need to stick a nail, small screw driver, screw or something similar in the socket's terminal, then, find a clean area (or clean an area) on the frame and touch the screw or whatever you used to the clean area and have someone turn on the ignition and watch to see what the gauge needle does.
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Senior User
Joined: Jul 2011
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Yes. The socket in the wiring harness is a female so you'll need to stick a nail, small screw driver, screw or something similar in the socket's terminal, then, find a clean area (or clean an area) on the frame and touch the screw or whatever you used to the clean area and have someone turn on the ignition and watch to see what the gauge needle does.
i will get back to you guys tomorow