How to fix GTV fuel gauge.
I had a dodgy fuel gauge on my '96 GTV myself which i managed to get working. I thought i'd share my experience and hopefully save you either some time or some money!
My gauge only ever read empty with the yellow warning light. These are the steps i took:
1. Check all the fuses and relays!
2. Remove the back seats to get to the top of the gas tank. Once the seats are removed you will see a black tarp like material where the backrests were. Unhook the material from the top two plastic buttons. Peel it back to reveal a brass cover. Unscrew the cover.
3. Once the cover is removed you should see the top of the gas tank. The fuel pump and fuel gauge sender are visible as two round screw caps. The fuel sender (what you wnat to be looking at) is the smaller of the two.
4. Disconnect the wires from the fuel sender. The connection snaps back together easily so this isn't hard. Short out the fuel sender circuit to earth. Do this by inserting a wire into both of the holes on the connection the fuel sender mates with. You are basically replacing the fuel sender with a short length of wire.
5. Start the car. The gauge should jump to max. If it doesn't the problem is with the wiring or gauge and not the sender. Removing your peice of wire and leaving the circuit open should give you a reading of nil on the gauge.
6. Assuming the sender is the problem, commence removing the sender. First disconnect the battery as you will be exposing the fuel tank to air and can't afford a stray spark! By all means try and unscrew the sender by hand but I found it impossible. Use a blunt chisel and a hammer if you cant unscrew it. Put the the chisel up against the ridges on the edge of the ring and start tapping at it. The sender screws off ANTI-CLOCKWISE.
Once the ring is off pull out the sender. Use a screw driver for leverage. Make a seal with some cling film or something and the ring the screws the sender to prevent your car from filling up with fumes. Take the sender inside!
7. Open the sender by removing the small plastic ring around its bottom. The sender should split into two halves. The long float should be exposed along with some metal contacts at the top. Remove the contacts from the plastic. Remove any gunk or corrosion with cotton wool, vinegar and baking soda. Clean until all surfaces especially the coil variable resistor is nice and silver again. Inside the cap you should see two copper contacts made to slide along the length of the resistor. Clean these as best you can but be careful as they are fragile.
8. Seal up the fuel sender once all electrical contacts have been cleaned. This is tricky as there are springs involved. Make sure the contacts are where they should be once the unit is sealed. Two holes on either side of the top will help you see inside and should show you if everything is okay.
9. The tough part now is getting the sender back into the tank without any jarring movements. Any knock could easily make the float dip too low and dislodge the contacts. If that happens you will have to open up the sender, reset the contacts and have another go.
Plug the sender into its connection and turn it (gently) upside down. Start the car and the gauge should read full. Do the same with the sender upright and the gauge should read empty. Get the float in the middle and it should read half full. If you can see all this happening you will have fixed your sender.
10. Open the doors and remove your cling film seal. As gently as you can sink the sender into the fuel tank. Take a peek at those two little holes befor it goes down the last two inches to check on the contacts. Screw the ring seal back on. Turn the ignition and you should get a reading for however much fuel you have left in the tank.
If the sender isn't the problem, check the connections at the back of the fuel gauge. To do this you must remove the center console.
Also I reckon silver dip would be an even better solution for the corrosion on the contacts!
Hope this helps!