Another Fuel Gauge Problem !!

[sparkerfix]

Hi All. First post after lurking for a while so please be gentle!

Anyway, I have a problem with our 1957 minor, using the gold speedo and fuel gauge. The fuel gauge works correctly with the unit (still bolted into the speedo) in my hand. When i put the speedo back into the dash the gauge the gauge reads full. It's as though there is an earth/leakage issue. I have removed all bulbs and tried again but again, whenever i ground the unit in the dash (or connect a wire between the back of the speedo and earth), the gauge goes to full. Connections are correct to the wiring diagram. Any suggestions?

Thanks in advance.

[Andy]

Hi Sparkerfix,

This sounds like there is a short circuit connection between the connecting post on the back of the gauge and the body of the gauge.

There should be a insulating washer between the nut that holds the post in position (the lower of the two nuts on the post) and the body of the gauge. Check that this washer is in position and is in good condition. Also check that the insulating sleeve between the post and the body (visible when you remove the washer) is in good condition and that there is no rust lying across it.

Check both posts but from your description it would seem that the fault is with the post marked T (for tank).

You should be able to get nylon washers from places like Maplin or perhaps even B&Q. Or you could make your own from a plastic milk bottle!

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Regards

Andy

[bmcecosse]

Check by taking the wire off the T connection - does it still read FULL when earthed?