Hey guys, I need help!

 

My fuel gauge isn't going out of the red, I filled the the tank up until the pump clicked off and I had put £40+ in the tank so I know there is defiantly fuel in there but my gauge is showing in the red (the fuel light doesn't come on though, just the needle). I've taken the fuel pump / sender out of the tank and the float moves freely without any issues. I'm wanting to bridge the power cable to force the gauge to show full but not sure which wires to bridge, anyone got any idea? (not looking to fake a full tank permanently just wanting to make sure the gauge is registering the current so I can hopefully narrow it down to a faulty sending unit.)

 

Any common problems people have experienced and fixed that could help me out?

Edited 3 October, 20169 yr by ShaneHiggs

If you short the Blue wire ( pin 3 ) to earth it should show full, if not you've either got a broken wire from the sender to the speedo unit or a duff gauge, is the water temp gauge working OK ? If you have access to VCDS you can test the fuel gauge to prove it's not a gauge fault

Water temp appears to be working correctly. Its on 0 when I first start the car the slowly rises up to 90 and stays there.

Ok that means the internal power supply in the speedo unit is working, as it powers both gauges. try shorting that wire and see what the gauge does, if anything. 

20 hours ago, nige8021 said:

Ok that means the internal power supply in the speedo unit is working, as it powers both gauges. try shorting that wire and see what the gauge does, if anything. 

I'll give it a go after work tomorrow just got home from a 12 hour shift so knackered.

On 03/10/2016 at 23:45, nige8021 said:

Ok that means the internal power supply in the speedo unit is working, as it powers both gauges. try shorting that wire and see what the gauge does, if anything. 

Just shorted the wire, nothing changed... I've noticed the fuel gauge goes from the bottom to the top of the red when I turn the key but it doesn't go higher or lower than that and when I had the fuel sending cable disconnected and conected to nothing else it still went to the top of red with the key turned....

Ok looks like the gauge is faulty then, if you can get it onto VCDS you can test the gauge to double check,  are you going to GTi fest at Santa Pod on Sunday ? if so I'll be there and I have the full VCDS

11 minutes ago, nige8021 said:

Ok looks like the gauge is faulty then, if you can get it onto VCDS you can test the gauge to double check,  are you going to GTi fest at Santa Pod on Sunday ? if so I'll be there and I have the full VCDS

Wish I was, I have work though :(

I've got a OBD to USB so I can connect my car to my laptop - not sure if this works the same as VCDS.

No a generic OBD reader/cable will not be able to test the gauges it needs to be a VAG based system like VCDS/Vagcom

6 hours ago, nige8021 said:

No a generic OBD reader/cable will not be able to test the gauges it needs to be a VAG based system like VCDS/Vagcom

Mine runs through VCDS and managed to read the gauge... Says there's a short in the plus - I'm hoping it's a fuse missing or blown so going to check them tomorrow.

If you got VCDS then in the instrument section 17 select output tests, and that will drive the gauges to full, back to zero then half way

11 minutes ago, nige8021 said:

If you got VCDS then in the instrument section 17 select output tests, and that will drive the gauges to full, back to zero then half way

I'll give it a go tomorrow :)