Fuel tank sender wiring

[fattogatto]

I have a new (made in Britain) fuel sending unit. There are three possible connections: one is the obvious ground spade attached to the metal plate. I have two other spade connectors that are labelled "W" and "T", and they are opposed to each other. My S3 wiring diagram shows a GB wire to the fuel gauge, and a B wire to the Earth Bobbin, with a smaller split off to what appears to be an additional grounding point. This I assume attaches to the grounding spade.

Can anyone help with the proper wiring of this sending unit with guidance as to which terminal should be connected to the GB wire going forward?

Thanks,

[h20hamelan]

W and T for different resistance?

[john.p.clegg]

I would assume one is for the gauge and the other for a low level warning lamp?

John

[fattogatto]

Makes sense. One have 50 ohm resistance and the other none.

[h20hamelan]

I had thought there are different resistances for different gauges

[pharriso]

T is the terminal for the Fuel level gauge.

[h20hamelan]

can you put a ohm meter on each terminal, raise and lower the float and post your results please

[fattogatto]

T is the terminal for the Fuel level gauge.

Thanks.

[HCA]

I would assume one is for the gauge and the other for a low level warning lamp?

John

Mine does not have any markings, but if it helps, here is what I have wired and it works...

[fattogatto]

Thanks for the replies. The picture shows exactly what I have and an ohm-meter verifies the proper connections.

[elansprint71]

I prefer to rely upon a piece of garden cane; in Chapman tradition it does two jobs, as it also props open the bonnet (hood) at just the right height.

Both my Elans have had gauges which read all over the place, a good dipper can't be beat!

I'll get back to you when the S4 project is back on the road; I notice that the DPO has fitted a new ally tank and new sender.

[ericbushby]

Garden cane, Pah!,
Mines a length of wooden dowel with paint rings at 2,4 and 6 gallons.
A much posher job. And a sort of doorstop thingy at one end to not scratch the paint off the well in the head when used as a bonnet prop.
Real class!
Eric in Burnley
S3SE DHC

[prezoom]

I personally could care less if my fuel tank is full. What I really care about is when the fuel tank is empty. Some of the back roads in my part of the world have long stretches where fuel is not available.. So, on the S2, I removed the tank and used an electric fuel pump to pump out what fuel was in the tank, to the point that the pump would no longer remove any more fuel. I used jumper wires to extend the signal wires from the car to the tanks sending unit. I then adjusted the float arm so as the fuel gauge needle rested exactly in the middle of the empty mark on gauge. I now know when to start puckering, and when to enter the panic mode. When the tank is filled to the maximum, the gauge now reads just above the 3/4 mark, but I know it is full because I just filled the tank. If my memory is getting a bit sketchy, I know if the gauge is close to the 3/4 mark, everything is just fine.

The Plus2 is another story. With the fuel tank outlet residing out the bottom of the tank, the last drop of fuel can be used. On that one, I drained the tank, and then added one gallon. Adjusted the float lever arm to show the same as the S2.