Original fuel sender unit

[Wookie 66]

Good morning all

I need some advice on my wagon fuel sender unit the tank is empty and when the ignition is turned on the gauge jumps to full.

The unit itself looks fine and seems as if works

I have wired it up as per the factory manual indicates, what else can I check?

Cheers

[DougT]

Hi Wookie 66, first thing to check is if the wires to the back of the fuel gauge are on the right sides, change them over and gauge should operate correctly. If this doesn't fix the problem then remove the sender unit from the tank, earth it to the frame and with the wire connected operate the float lever to see if the gauge needle moves in order the confirm correct operate of the sender and if sender wire is not shorted out. If nothing happens other than the needle sitting on the full mark then check wire from the gauge to the sender for continuity. Hope this helps Doug

[Errol62]

Showing full indicates resistance over 70 ohms in the circuit. Check and clean all electrical connections.

You can test the gauge itself by removing feed from sender terminal. Gauge should read above full. Then earth the feed. Should read empty. The gauge rarely fails.

Pass above, try earthing the sender body direct to negative terminal. If gauge reads normally then it's an earthing issue. If not it is the sender itself.

Pull the sender and measure resistance st full and empty float positions. If I remember correctly should be less than 6 ohms empty and more than 70 ohms full. Something like that.
Cheers
Clay

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[Wookie 66]

Ok great thanks for the info I’ll look at it on my next day off

Cheers

[Dr_Terry]

Showing full indicates resistance over 70 ohms in the circuit. Check and clean all electrical connections.

You can test the gauge itself by removing feed from sender terminal. Gauge should read above full. Then earth the feed. Should read empty. The gauge rarely fails.

Pass above, try earthing the sender body direct to negative terminal. If gauge reads normally then it's an earthing issue. If not it is the sender itself.

Pull the sender and measure resistance st full and empty float positions. If I remember correctly should be less than 6 ohms empty and more than 70 ohms full. Something like that.
Cheers
Clay

Sent from my SM-G973F using Tapatalk

AFAIK the correct resistance for all early Holden fuel gauge senders (FX to HG) is 0 ohms empty & 30 ohms full scale.

Dr Terry

[Wookie 66]

Hi all
Had a good play around must have been an earth issue as it’s now working sort of 

one small issue tank is empty and he gauge reads 1/4

I think I have one of those pesky gremlins might need  set some traps

Thanks for the info much appreciated
Cheers

[mcl1959]

Does it read 1/4 full with the sender out of the tank or in the tank or both?

Ken

[Wookie 66]

When the sender is out it jump to full
If I earth it and move the mechanism it work the gauge from full to empty it only goes down the 1/4 mark though

[Errol62]

A good clean inside may fix it. Had the same problem but found a working one before I got to the point of trying to fix the old one. Don’t bother trying bending the arm either, as someone suggested to me on another forum. Basically it isn’t allowing full voltage. Could be either worn or dirty contacts in the rheostat inside.


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[mcl1959]

The sender is faulty, easiest to get either try a second hand one or get one from Rare Spares

[Fraze]

Interesting topic this. When i restored my FB (It's been on the road for 12 months now) I fitted a new Rare spares fuel sender unit and it has given me nothing but grief. The arm keeps on sticking so that you really don't know how much fuel you have. I have added weight to the arm near the float but this has made no difference. When I remove the sender and work the arm up and down a few times it frees up but put it back into the tank and it sticks again. It seems to stick at the !/2 to 2/3 mark. I have had it out 5 or 6 times now and this week i lost patience and removed it and refitted the original unit which seems to work fine except with the arm right down it still reads a bit under !/4 full. I bent the stop tab out of the way to get more travel for the arm but that didn't work. I wll just put up with it knowing that at 1/4 full i should refill te tank. Cheers Fraze

[Wookie 66]

Interesting thanks for the info I may as well save the $170 and just put up with the gauge as is
It’s not any every day driver so I’ll just fill up after use

Cheers