Please Help Me With My Fuel Gauge!

[dravidham]

Hi all,

After having a rather bad run on the mechanical side of my car (failed clutch, starter motor and ABS control module, all of which I have now had fixed) I think that with just one exception everything on the car is now A1.

The exception:-

Ever since I replaced the starter motor (and this might be a total coincidence) the fuel gauge only seems to work intermittantly. The best example I can use is that I can, say, start the car up and the gauge will not register a reading even though the car has a full tank of petrol. But every 5-10 minuites in to a journey, the gauge needle will then shoot up to read the correct level of fuel for five seconds or so, before returning back to zero.

Have any of you an idea as to the likely cause of this issue? - maybe I have knocked a wire somewhere, but to be honest I have checked the ones under the bonnet near to where I have been working on the starter motor.

Hope to hear from some of you.

Thanks,

David.

[passat boy]

Hi all,

After having a rather bad run on the mechanical side of my car (failed clutch, starter motor and ABS control module, all of which I have now had fixed) I think that with just one exception everything on the car is now A1.

The exception:-

Ever since I replaced the starter motor (and this might be a total coincidence) the fuel gauge only seems to work intermittantly. The best example I can use is that I can, say, start the car up and the gauge will not register a reading even though the car has a full tank of petrol. But every 5-10 minuites in to a journey, the gauge needle will then shoot up to read the correct level of fuel for five seconds or so, before returning back to zero.

Have any of you an idea as to the likely cause of this issue? - maybe I have knocked a wire somewhere, but to be honest I have checked the ones under the bonnet near to where I have been working on the starter motor.

Hope to hear from some of you.

Thanks,

David.

Hi David,
assuming it's a (1995 0nwards)audi or other vw car youre refering to,the needle's are just stuck into the circutboard and a tiny coil on the circut board responds to voltage.Ive never come accross loose needles and these new types can be opened to repair easily but if you replace the whole cluster then it must be reprogramed to the cars electrics(ecu/alarm etc)but you wont be able to drive the car so fitting&programming must be done at the dealer or a private garage.If you have the old pre 1995 car then remove the cluster unit and look for corrosion on the circut board around the fuel gauge area and on the circut board in general but first try removing the fuel pump(with fuel gauge sender attached) and looking at the sender unit coiled wire that sends the fuel level to the clock display.These senders attached to the fuel pump can be replaced seperatly as they do fail after 8 to 10 years on the odd car(friday jobs).Open your boot and it's usually on the top right near the rear seat under the carpet,theres a round saucer type disc with 3 screws and its under there.Removal is easy but requires small hands and a push and twist action to remove(push&twist to left)

[dravidham]

Thanks for the info passat boy - it's appreciated.

The car is indeed a late 1995 model.

Here's a pic of my boot from when I was soundproofing it for my ICE install. The saucer disk you describe will be that thing that I have painted five coats of sound deadening over, which you can just make out the three screws on then. Time for me to get the stanley knife out



I'll have a play at the weekend.

Cheers,

David.

[passat boy]

Thanks for the info passat boy - it's appreciated.

The car is indeed a late 1995 model.

Here's a pic of my boot from when I was soundproofing it for my ICE install. The saucer disk you describe will be that thing that I have painted five coats of sound deadening over, which you can just make out the three screws on then. Time for me to get the stanley knife out



I'll have a play at the weekend.

Cheers,

David.

Youre on the spot,just dont cut the cable's top centre of the cover.To test the sender unit in the tank(not smoking or playing with any source of ignition)just remove the connector socket,then the 2 fuel lines(fuel&return line)very gently with by using a plier(widemouth)to press the clamp squareish(the origional is crimped)and this loosens it up a little. next a left right turn using a decent plier without the strenght of a madman to slowly wiggle the pipes off and there will be a few drops of fuel so be carefull or youll have a very hot day to remember.next is just to tap the black collar off anticlockwise till loose(use a blunt wide chisel or other flat steel object and knock gently without destroying anything.once off the top of the pump is 2 tubes on a round disc that can be shifted out of the way(only a few cm so you get your hand in the tank)looking in youll see the float(orangy colour ball)on the right,connect the fuel hoses(just to stop fuel spillage)and the connector and have someone turn the ignition on but do not start the car!!!!!!!.let them tell you what the needle does then lift the float gently higher and if the needle doesent respond accordingly or creeps then thats the fault and you only need source a new sender but they are avaidable.keep the tank clean dont let dirt get inside.good luck.

[dravidham]

Thanks mate. I've just found out I have to work tomorrow so I will have a look at this on Sunday and I'll post back.

Cheers,

David.

[dravidham]

Youre on the spot,just dont cut the cable's top centre of the cover.To test the sender unit in the tank(not smoking or playing with any source of ignition)just remove the connector socket,then the 2 fuel lines(fuel&return line)very gently with by using a plier(widemouth)to press the clamp squareish(the origional is crimped)and this loosens it up a little. next a left right turn using a decent plier without the strenght of a madman to slowly wiggle the pipes off and there will be a few drops of fuel so be carefull or youll have a very hot day to remember.next is just to tap the black collar off anticlockwise till loose(use a blunt wide chisel or other flat steel object and knock gently without destroying anything.once off the top of the pump is 2 tubes on a round disc that can be shifted out of the way(only a few cm so you get your hand in the tank)looking in youll see the float(orangy colour ball)on the right,connect the fuel hoses(just to stop fuel spillage)and the connector and have someone turn the ignition on but do not start the car!!!!!!!.let them tell you what the needle does then lift the float gently higher and if the needle doesent respond accordingly or creeps then thats the fault and you only need source a new sender but they are avaidable.keep the tank clean dont let dirt get inside.good luck.

Just a quick note to say that things are now at long last sorted. I bought a s/h fuel sender and fitted it and the gauge now works a treat.

Thanks for your help Passat boy