2 replies to this topic

[Razor]

Hi

I installed a 3 clock Magnolia Gauges in to my '76 Australian Clubman and the fuel gauge is reading half full, it goes down like normal. I tried swapping the wires on the fuel sender and the pointer went to the top way past full icon and doesnt go down.

Someone told me to bend the fuel sender arm in the tank.

Please advice

Thanks

[Dan]

The instruments on Australian cars were one of the locally produced components so it's unlikely a late instrument pack (all of which are Nippon Seiki worldwide spec) will be compatible with the original sender. The best thing to do is fit a late sender unit to the tank (presuming it will fit, being locally made the fitting may be different as well). Failing that you need to determine the resistance range the gauge requires and the range the sender supplies and calculate what value resistor is needed to shunt the output into the correct range.

[dklawson]

If you don't have one, buy a multi-meter as Dan suggests. They have lots of uses other than car repair.

In the boot, notice the two wires on the fuel sending unit. The sender should have two spade lugs. One will clearly be spot welded on and the second will be on a little plastic insulating pedestal. The spot welded one should have the black wire on it, it is ground/earth. The insulated spade lug is the connection point for the green/black wire which goes to the gauge.

Remove the two wires and connect your volt/ohm meter to the spade lugs. Use a coat hanger through the tank's filler neck to lift and lower the float to its extremes while you monitor the meter. Full up should be about 30 ohms. Empty should be read close to 240 ohms. That's the standard Mini range and I don't think that changed on cars from Oz or NZ. If you don't get the full 240-30 ohm range, that would probably explain your dash gauge readings.

When you switched the two wires on the sending unit, you effectively connected the green/black wire to ground. This gave the gauge a 0 ohm signal. So... your gauge went to Full... just like it was supposed to. In fact, this is a standard test performed to troubleshoot fuel gauge problems.

Confirm the resistance range your gauge works through and post back again.