OHMs for fuel guage

I salvaged the speedometer and 4 gauge cluster from a rusted out 72 SJ headed for the crusher. I would like to give them a new life in a 30 Ford coupe. Does anyone know the OHMs range for the fuel gauge so I can get an after market sending unit for a custom tank I need to make? Thanks in advance for any help you could give me. Bob

72 XJ6?

IIRC the range goes from zero resistance. (Full fuel tank) to about 160-170 Ohms, but that is not a fact, just how I remember it since I fiddled with the fuel tank sendets the last time.

Maybe Paul @Wiggles would know, although I think his Jee-Type doesn’t have that many Jag related instruments.


As in none, so Im of no help!

Its fuel gauge is a crude cork float…:laughing:

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I think it’s 25-250, it’s definitely not 0 when full because the gauge pegs when you short the wire to ground.
The senders are simple and you could adapt one if you’re making a custom tank anyways?

Hi David,

Thanks, I think you are right. But also I think there are two different setups for the senders and that must also be related to the gauges. One connects to the ground and one just changes resistance of the (positive?) feed.

Easy to test when the sender is out.

And to the OP: do you have one or two wires to the sender?


Thanks for the responces. I salveged several things from the car but I did not think to (stupidity ) get the sending unit. I am building a vertical tank, 16" tall with baffles and am not sure the swing arm would have enough room to operate properly. Does anyone know how many inches the arm needs to function. I was thinking an after market tube type ( non swing arm ) sender but if an original sender could be made to work I would go with that. Bob

The solution is a product called “Meter Match”. It will let you use any sender with any gauge…. Unless it is a positive ground Arnolt MG, in which case it is totally useless and now available for sale: $40+ shipping and its yours.

Get the E type sender, it has a low level warning light and is not so expensive. Also it is bolted in so probably easier than the bayonet the XJ uses.
Adapt it to suit the tank you’ve got. You have the sweep of the arm, the larger the change in height from empty to full the longer the arm must be. Get a gauge and draw it up, experiment.

It’s easy to adapt, ground via body, one wire for level, one for the warning light.

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The baffle chambers will be about 12" wide and if the E tank is less than 16" deep than lengthening the arm would be necessary as you stated. I was hoping not to buy anything until I knew that I could make it work, so knowing the depth of the E tank, if the sender is mounted on the top of the tank and the length of the swing arm I can’t do the math to figure out how much the arm might need to be lengthened and therefore still fit in the baffle chamber. Thanks again Bob

Points to ponder, Bob;

  • The Jaguar tank is odd shaped and the gauge
    reflects that; the resistance in the unit just
    reflects fuel level irrespective of fuel volume…
  • You need to know the difference in ‘empty’ and
    ‘full’ levels in ‘your’ tank. If equal to the Jaguar
    levels; it’s a direct fit - but ‘1/4’ or ‘3/4’ full will
    be wrong in ‘volume’ if your tank is ‘straight’. -
  • The length of the arm can be varied, but the
    angle of deflection, full/empty, must be the
  • It is possible to ‘adjust’ the tank unit’s
    resistance for different sweep angles by
    adding a resistor in series or parallel. Or
    indeed use a tank unit from other cars - with
    similar use of resistors to suit the Jaguar

Ie, you can sure make the set-up work, but it is unlikely to be very precise - unless you shape your tank like the Jaguar’s.

xj6 85 Sov Europe (UKNZ)

I would draw the tank on paper in real size and then place the fuel sender and see how you can adapt it.
If you can’t make it work that adaptor thing might be useful.

The sender is not adapted to the tank shape, it is a standard part used in hundreds of different applications…