guage not working

[jonboy]

fuel guage doesn't work,

ideas on how to solve it? fuse relays? couldn't see a connection to the tank either when underneath it.

[Amit]

I have a similar issue and there is a good section on testing it in the haynes manual.

Apperently, if you disconnect the two wires from the sender unit in the top of the tank, and wire a 47 ohm resistor across the terminals and it should read empty, 100 ohm should be the first mark, and 220 ohm should be full tank.. or something like that.. this is all from memory so I will update it when I get home.

I have also figured out that pin 4 (purple/white wire) on the dash plug is the fuel sender wire.. altough I am not quite sure how you test this. I think you just measure the resistance between that wire and ground.

Also.. with only 1 galon of fuel in the tank, the gauge should read reserve.

Amit

[CADDY-SPORT]

Pull the wire off the tank sender. This wire should carry 12V. The sender is then grounded thru the tank to the body. Stick the wire to ground (any piece of bare metal) and the gauge should fly up past maximum. Don't hold it there for more than a few seconds else it'll start getting hot. That will prove the gauge. If it doesn't move check you have 12v at the sender wire. If you do not have 12v at the sender wire then you need to find some voltage from somewhere. Either replace the cable to eliminate any breakages or just grab 12v straight of the battery and run a temporary wire down to the sender to test the gauge. If you have 12v on the cable and the gauge doesn't move you need to replace the gauge. If you DO have 12V and the gauge doesn't move you will probably find your sender is full of fuel and not doing its job at all. New sender required.

Option 2:
Forget the gauge and get a 2 foot long stick!
Fill the tank full and mark the stick. Dah Nah! no need for senders or gauges.

[Wagenryder]

Option 2:
Forget the gauge and get a 2 foot long stick!
Fill the tank full and mark the stick. Dah Nah! no need for senders or gauges


Fuel gauge on my Ford Ranger quit working because the float cracked and filled up. Rather than replace it I just keep resetting the trip meter and refill every time I get past 400 miles. Only run out once since then when my son borrowed the truck, only put ten gallons in and reset the meter.

[animal]

this could also be the little 3 pronged resistor on the back of the instrument binnacle.

[CADDY-SPORT]

this could also be the little 3 pronged resistor on the back of the instrument binnacle.

Could be. Normally when that goes you get a full reading constantly. It shorts itself and feeds the gauge 12V. If it goes fully open circuit then it would not show anything on the gauge. I'll be breaking a good mk1 4 door soon with a corking dash. Then you get a full instrument panel with newish electronics. Its only done 70k miles. I'll post when i kill it.

Anyway back to the resistor. I would think you would get a very eratic gauge before the resistor went, if that is the case. Did you spot any weirdness?

Ta

[jonboy]

no, no wierdness,

been a long time since it had any fuel...it has a least £10 in there of diesel.

opened up a few things but no joy on the electrics...:( couldn't really assertane if the tank was getting power or the dash, checked my mk1 golf and it gave a similar reading which only confused the matter...

swapped the clocks too but no joy...

oh well the fault finding continues with it all

[CADDY-SPORT]

If the tank has been dry for a while the float in the sender unit might be stuck. I would stick half a tank in and gently tap the tank under the sender with a mallet. That might release the float. If it doesn't i would say your float has split and is full of fuel. If the float don't float you won't get a reading.

[squeegy]

Both my brother's and my Caddy both had inoperative fuel senders. New replacements are available and it gave me a chance to drop the tank, check for leaks, and to replace all of the hoses associated with the tank. By doing so, the fuel vapors I smelled inside the cabin were completely eliminated.

The sender unit is on top of the tank so it has to be dropped in order to gain access. When I removed my original, I could clearly see that the brushes on the sender unit were missing. It was the same on my brother's truck. The sender unit is the round item on top of the tank. It spins off.

There is a gasket underneath that has to be replaced. Be very careful as the fuel vapors are explosive. Have plenty of ventilation and a fire extinguisher handy. And discoonnect that battery before you begin.

Now the gas guage works perfectly
http://img.photobucket.com/albums/v78/squeegy200/VW%20Truck%20Project/tank.jpg