Fuel Gauge on E

[motoboy549]

My fuel gauges are both on slam "E" it dont matter what tank (which i dunno if thats even workin i needa switch it to the back tank and drive it around HAHA) Because of the gauge i just keep it full like seriously fuel every or every other day. Whats the most common issue that would make that a result

 

[Logroller]

check the plug on to of the tanks and make sure they are pushed down all the way ,, if they are then its either a sending unit issue or its a ground issue either on results in this problem

 

[87crewdually]

If it's the same "E" on both tanks check the plug on the fuel selector valve that's on the frame rail where the fuel lines are plugged into. This valve changes the gauge inputs from the senders when you change tanks.

 

[4x4dump]

check the floats. both of mine had holes in them.

 

[Hybrid455]

If it's the same "E" on both tanks check the plug on the fuel selector valve that's on the frame rail where the fuel lines are plugged into. This valve changes the gauge inputs from the senders when you change tanks.

check the floats. both of mine had holes in them.

The guages on the older trucks default to full when the signal wire is open to ground. Your signal wire is either shorted to ground via damaged switching valve, rubbed through or pinched wires, damaged connectors, or your floats have sunk. If its a short it could be anywhere from the gauge to the tank. If both tanks are effected for the same reason then the concern is most likely between the swithching valve and the gauge. Disconnect the senders and see if the gauge goes full. If it does you know you don't have a short to ground between the senders and the gauge. That only leaves the floats. If it remains on E then you have a short to ground on the signal wire. Try disconnecting the switching valve and look for the gauge to move to full again. If it does then the switching valve is most probably at fault. If not then you can isolate the short to ground by systematically moving along the harness and disconnecting connectors that carry the signal wire until the gauge eventually goes F. When it goes full then you know you have removed the shorted section of harness. Simply back track from the last connector that you disconnected carefully inspecting wire, connectors and pins until you find it.

 

[MIDNIGHT RIDER]

I put my gauge wires on a DPDT toggle-switch for the same problem you are experiencing.

The DPDT has never failed me; I can't say the same for the many electric selector valves I have wasted money on.

Before getting in too deep, I would un-plug and clean the terminals at both tanks and also the plug at the tank-selector; that did fix mine for a while many years ago.

For what it's worth, when I move the DPDT switch to the center OFF position, the gauge goes to "E", not "F".

 

[Hybrid455]

I put my gauge wires on a DPDT toggle-switch for the same problem you are experiencing.

The DPDT has never failed me; I can't say the same for the many electric selector valves I have wasted money on.

Before getting in too deep, I would un-plug and clean the terminals at both tanks and also the plug at the tank-selector; that did fix mine for a while many years ago.

For what it's worth, when I move the DPDT switch to the center OFF position, the gauge goes to "E", not "F".

If when you move the switch to "center or off" and the guage goes to e then your signal wire, as I remember a yellow wire with a white tracer that flashes when probed with a test light, is finding a direct path to ground.

 

[85f250dually]

just a thought but have you checked the tank selector fuse i had almost the same problem in my 88 and found that the fuse was gone put one in and the switch works again.
Jeff

 

[MIDNIGHT RIDER]

If when you move the switch to "center or off" and the guage goes to e then your signal wire, as I remember a yellow wire with a white tracer that flashes when probed with a test light, is finding a direct path to ground.

All I know is that the gauge always reads accurate, especially so after I custom-bent the float arms; after my tuning of the float arms, "E" is bone dry and "F" is pretty much FULL.

If it has a short to GROUND, it sure doesn't affect the working of the gauge.

I flip the toggle forward and the gauge reads the fore tank; flip it aft and it reads the aft tank; flip it to center = OFF and the needle goes to "E".

 

[87crewdually]

All I know is that the gauge always reads accurate, especially so after I custom-bent the float arms; after my tuning of the float arms, "E" is bone dry and "F" is pretty much FULL.

If it has a short to GROUND, it sure doesn't affect the working of the gauge.

I flip the toggle forward and the gauge reads the fore tank; flip it aft and it reads the aft tank; flip it to center = OFF and the needle goes to "E".

Goes to E because it's an open cicuit, NO resistance through the sender= NO reading on gauge.

 

[MIDNIGHT RIDER]

Goes to E because it's an open cicuit, NO resistance through the sender= NO reading on gauge.

That's exactly what I thought.

 

[jim x 3]

Goes to E because it's an open cicuit, NO resistance through the sender= NO reading on gauge.

That's exactly what I thought.

Have you guys actually tested your fuel guage systems - I have tested mine (stock 1988) and it works like Hybrid has said in his posts above. The factory wiring diagram indicates low ohms at low fuel level and high ohms at full - actually 22.5 ohms at E and 145 ohms at F.

When I measured my fuel senders and guage, I got 30 ohms at E (79.3 ma) and 161.5 ohms at F (34.5ma).

And please tighten up your terminology. An analog guage always provides a reading - there is never "NO reading on the guage". An open circuit is infinite ohms - this should read to Right of F on the guage. No resistance = 0 ohms = dead short to ground - this should read to Left of E on the guage.

Regards,

 

[6 Nebraska IDIs]

I had this problem with my little 2wd truck when I bought it. The easiest fix for it was to rewire the fuel selector swtich because thats where everything flows through. I gave it new power and new grounds and everything started working properly. Can't tell you without pulling the thing out what wires are supposed to be 12v+ and Neg/Gnd. Hopefully someone here has the diagram.