Fuel Gauge not working.

[Joe M 0]

Ok, heres the story. About a month ago I had to change my fuel pump, I got a hold of a g60 pump temporarily and it worked fine but the sender wires were cut so I fitted the pump without the sender. the two extra wires for the sender I didnt want to leave hanging in the tank seperate so I joined the 2 of them together thinking it will either show a full or empty tank.

Ignition on, everything fine, tank shows full. I started the car and the gauge dropped to empty and stayed there since. I assumed the wires had come detached due to vibrations or the fuel swirling round but it seems I was wrong.

Ive now fitted a new fuel pump and my old sender unit that I know is good but the tanks still reading empty.

So

 

Is there a fuse for the fuel gauge on its own, cause if there is I cant find it and evertything else is working ok.

Or

Have I damaged the actual gauge and may need to replace the clocks?

[Kevin Bacon 5]

I can't see what you did with the wires as being a problem. Shorting them together = zero resistance, i.e. full tank. Maybe that circuit, or more importantly the guage itself is intolerant of short circuits? I would suggest trying your instruments in another Corrado (if possible) or getting a crummy old cluster from a breakers to see if the guage has been damaged?

 

I don't think there is a fuse for the fuel sender part of the pump.

 

Funny old thing these pumps.....all I did with mine was get a VR6 4bar one from GSF, binned the supplied sender (Golf VR6) and slot my old sender in it's place and off I went..... well, Stealth did it, but it all seemed compatible and fine......

 

BTW, each module in the clocks is available seperately from VW.... for instance the rev counter is £37. Should be cheaper for the fuel guage.

[Joe M 0]

Yeah, I thought it would have been fine as well, and it was with just the ignition on. It was only when I started it the gauge went to full and then dropped immediately to zero which is why I was thinking blown fuse.

[Joe M 0]

Anyone got any other ideas?

[bcstudent 0]

If it was me I'd whip the clocks out and check the coil in the fuel gauge that heats the bi-metal part has continuity. If that's the case then there should be no reason that the gauge does not work and this could even be checked by driving the gauge up and down on the bench. Attention can then be turned to the sender if the gauge checks out.

 

Obviously this check relies on your clocks working in the same way I believe the early 16v clocks to work - my temp. and fuel guages take a while to react so I can only imagine they're bi-metal. I have no doubt that the VR6 clocks are waaayyyy more complicated though, 'cos life's like that!

[Henny 0]

bcstudent, nope, they're a bi-metallic strip too, same as them all... it was only the speedo which got changed in a major way... 8)

[Gman 0]

What sort of signal does the sender put out?

it is just high resistance when no fuel and low when full?

 

Also is the sender unit easy to get at?

 

G

[Supercharged Junkie 0]

On the subject of fuel gauge, i just fitted a vr6 fuel pump & sender to my G60 and the fuel gauge is about a 1/4 of a tank out now. I see there is some kind of adjust screw on the side of the sender but what tool is needed to adjust the screw ?

Looks like a really small allen key is needed or is there a special vw tool required ?

What would be an easier way of adjust it ?

 

Cheers

 

Ian

[bcstudent 0]

What sort of signal does the sender put out?

it is just high resistance when no fuel and low when full?

 

Also is the sender unit easy to get at?

 

G

 

If the gauge is bi-metallic then the sender will be resistive, yes. It will work exactly as you describe but as for getting at it I have no idea. I'm only familiar with the two pump setup as found on the Mk.2 Golfs and 16v Corrado.

[Joe M 0]

The sender is fairly easy to get at, unscrew the cover in the boot, loosen and remove the lockring on the tank (hammer and flat screwdriver) then the cap will lift off allowing access. The sender will have 2 wires on spades on it and it simply unclips from the pump.

 

Still havent had a chance to look at mine, but am I right in thinking the 2 wires from the sender go to the gauge, then there will also be a power lead on the gauge?

So I first need to check if im getting power to the sender, if none check if theres power going to the gauge:

power to gauge means gauge knackered;

no power to gauge means possibly a fuse ill need to find somewhere?

[bcstudent 0]

The sender is fairly easy to get at, unscrew the cover in the boot, loosen and remove the lockring on the tank (hammer and flat screwdriver) then the cap will lift off allowing access. The sender will have 2 wires on spades on it and it simply unclips from the pump.

 

In that case it's exactly the same as the 16v Corrado!

 

I would expect the fuel gauge to have two connections - one will be a live connection to the voltage regulator in the clocks and the other will be to the sender. The second connection on the sender will be connected to ground, i.e. the varying resistance of the sender unit regulates the flow of current in the circuit and, hence, the heating effect of the bi-metallic gauge.

[bcstudent 0]

Something like this probably.....

[Joe M 0]

Ah, got it. Chances are then its the gauge thats knackered if it shares power with the rest of the clocks, as there all fine.

[bcstudent 0]

A quick resistance test of the gauge heater coil should be enough to confirm that. I don't think the instrumentation gets any simpler than the fuel gauge!

[Gman 0]

ok cool

Will have a look tomorrow. thanks.

[Joe M 0]

Sorted 8)

It seems that when I had the wires connected and there was no resistence where the sender should be it caused the needle to move too much and something popped out of place. I took the clocks out today, moved the needle a bit and felt it click, put the clocks back in the car for a test run and they worked. :D

[bcstudent 0]

Sweet. I'm sure this thread will save someone else some grief in the future. Glad you're sorted.