Gas Gauge doesn't work

[EastYorkStang 63]

If I remember the wire leading to the tank measures the level through ground? So If I run a jumper wire from the disconnected wire to another ground the gauge will do what?

 

My Oil gauge also starts working and then falls after a few seconds. Is this fed through ground as well? I don't have a separate Oil gauge to check the validity of the dash.

[Print Dad 58]

Hello EastYorkStang,

If you pull the wire from the sending unit in the tank, and then run a ground to it, if the key is on the gage should go to full.

 

I am pretty certain the oil works through a ground. Mn ay people wrap plumbers tape abound the base threads, but I learned this affects the grounding of the switch.

 

Hope this helps a little........ Print Dad

[Pakrat 1,043]

Here's a nice little Q&A form of the test for you.

 

With the ignition switch on, remove the wire from the fuel tank sending unit and ground it to the unit housing. This removes the resistance supplied by the sending unit, and should cause the gauge to swing over to the 'Full' position. Does this happen?

 

Yes

 

The gauge and wiring are good. The problem is most likely with the sending unit. The sending unit must be removed for further testing.

 

No

 

Ground the sending unit wiring to a good chassis ground (instead of the sending unit housing) and watch the gauge. Does it now peg out to the 'Full' side?

 

Yes

 

 

The problem is with the sending unit ground. Either the unit itself is bad or the float/arm is binding/missing. The sending unit must be removed for further testing.

 

No

 

The power supply to the gauge has been interrupted, (check fuses), the gauge is defective, or the wire from the gauge to the sending unit is open or has a break in it.

 

 

Testing the Sending Unit

 

After the sending unit has been removed from the tank, check to make sure the float is present, intact and still floats and that there is no binding with the float arm. Reconnect the gauge wiring to the unit and ground the unit. Move the float arm up and down. If the gauge reads full in the full up position and empty in the full down position, then the sending unit is good. Verify by hooking up an ohmmeter to it and making sure it reads 8-12 ohms full and 70-73 ohms empty. If not, the sending unit needs repaired or replaced. You can easily disassemble the head of the sending unit to clean and/or repair.

[EastYorkStang 63]

Thanks for the information. Replaced the oil sending unit already. The tank is next...

[ausstang 10]

Just like to add to this post.

 

Do not use a test light to check the wiring & gauge to ground.

It seemed like a good idea to carry out Pakrats test using the test light to complete the circuit but i could not get my gauge to go past a 1/4 full.

After some trial & error i finally figured my mistake & used a regular piece of wire then the gauge climbed all the way to full :001_smile: (last thing i wanted was to be pulling my Dash AGAIN)

Pulled the sending unit for inspection to find brand new float had filled with fuel, (easy fix).

 

Again this forum provides so much information from a simple search making an otherwise daunting task simple.

 

THANKS GUYS..........Vic.

[LoneWolf2U 136]

Using a testlight in this type of testing willeather not work or give false readings.

The power or resistence consummed by the bulb is why it doesn't work.