Removing Fuel Sender on VR Commodore

[jwex]

I have to remove the fuel sender on my wife's VR commodore and thought I would ask if there are any special tricks or precautions I should take.

I've located the fuel sender plate on the front of the fuel tank just behind the diff.

Is it just a case of undoing the 5 little bolts and withdrawing the sender unit or does the plate have to rotate as well?

Are the senders usually buggered or do they just need a clean?

How much do they cost (new) or (wreckers) and is it advisable to get new on this particular part?

Will the fuel pump be attached and does it need any special precautions?

I've done some diagnostics and think the fuel sender is the problem because:

1. The gauge only goes up about a mm from empty even though the tank is full.

2. When I remove the sensor wire from the sender unit and earth it, the gauge moves slowly up above half full.

3. When I check the earth wire from the sender unit with a meter, I have a good solid earth.

Any help greatly appreciated so my wife can be happy again. (Happy Wife, Happy Life)

Thanks

John

 

[wortus]

If you earth the fuel gauge I'd have thought it should move to full as it's zero ohms so there may still be something wrong with the fuel gauge. Are you saying the wire from the sender that go9es to the gauge is at earth yet when it is connected to the gauge you get a different reading than if you earth the wire to the gauge, strange!How many ohms is the sender wire reading to earth? You can also take the sender out of the tank and check it with an ohm meter and you may even be able to fix it?

On a VR the fuel return goes into the sender plate and there is a hose inside the tank you have to uncouple and you have to be careful not to loose it in the tank or pull it off from inside the tank. To get it out you have to rotate it a bit and as the float approaches the opening turn the whole thing and take the float out first otherwise it will be damaged.

I've got no idea how much they cost new but it can't be that much from a wrecker however you'd need to find out the resistance range and test it first. When you change it you need a new gasket and don't over tighten. I usually use some stag joining paste, the pinky red stuff. I'd also consider replacing the fuel pump and filter while your at it as the fuel pumps often fail and if you don't know how long it has been in there for it's cheap insurance because if it breaks down it's a tow home. I bought a genuine one from a local dealer with a gasket for about $100.00

 

[jwex]

Thanks Wortus,
What I meant was I removed the wire (that normally carries current to/from the gauge) from the sender unit and earthed it to the body, thus getting the current flowing and bypassing the resistance in the sender unit. The gauge went up slowly but I stopped after half way because the VR petrol gauge is always slow to react. It may well have gone all the way up if I had waited longer, but it was on dusk and the mozzies were starting to eat me alive.

Haven't done a resistance test yet. I'll have a go when I get the sender out and cleaned up. Thanks for the instructions.

regards

John

 

[wortus]

You may be able to fix the sender once it is out it depends on whats wrong with it it's basically a resistance on a circuit board with a wiper arm that moves over it , the wiper arm may contact may have lost tension, there may be a broken wire or the resistance section may be broken. Let us know how you go.

 

[jwex]

I won't attempt it over the easter break because no one will be open if I stuff it up. I certainly will let you know how I get on. Thanks for the help.

 

[wortus]

No probs. also when you remove the sender from the tank it's a good idea to syphon as much fuel out as you can or drive it until it is almost empty and raise the car at teh front and back to prevent too much fuel leaking out. Reason is it will sting your hands and also it will run down the tank and make a sticky mess out of the bitumen under the aluminuim tape that's meant to protect the fuel tank where the straps hold it.

 

[jwex]

Will do. Thanks mate.