3 replies to this topic

[Nils]

Recently, I have a problem with the fuel gauge.

It is old school smiths speedo assembly from 1969 mini. When fuel tank is full, it reads really full, when empty it reads 1/4 full. It seems to be smooth in its action, and doesnt stay at 1/4 full for a while till I run out of petrol. It is like it has become overly optimistic in its old age.

Any help? - voltage regulator out of whack?

Also, the speedometer is really jerky, If I give it a bash with my fist, it jumps up to the correct speed. Need some sewing machine oil? The spedo cable is new and screwed in tight.

Thanks - Mini 1000 - 1969 - Australia

[dklawson]

If you are adventurous, Google for and download Anthony Rhodes' 27 page PDF on "Repairing Jaeger and Smiths Speedometers" so you can work on the gauge yourself. Or... send your speedo to a gauge service company. If the jerky motion is not being caused by a cable (and you said yours is new and attached properly) the jerky needle can be caused by dirt and debris in the needle bearing that supports the pointer. However, most old Smiths speedometers will have needle wobble to some degree. One that bounces above and below the actual speed by +/- 2-3 MPH would be typical.

The fuel gauge problem is interesting. You need to try some things and post a bit more information. When you fill up the tank, is the needle on full... or way above full? How is your temperature gauge behaving (assuming it's electric)? Where is the fuel gauge needle before you turn on the ignition?

[Nils]

There is no temp gauge - just a warning light (which doesnt work). The fuel gauge is showing below empty when The ignition is off. when the tank is full, the gauge shows way above full.

The speedo is not wobbly, just gets stuck, then jumps as the car accelerates

Thanks

[dklawson]

A stuck speedo that can be freed by tapping the glass (or pounding the dash) sounds like what I was describing earlier, dirty needle bearings for the pointer. You can attempt cleaning this yourself (find and download the PDF I mentioned above) or you can send the speedo in for a professional servicing.

The fuel gauge reading WAY over full when the tank is full indicates that the voltage stabilizer probably has problems. There are some things to check before replacing it.

You said that the speedo is from a '69. Therefore, the voltage stabilizer should be mounted on a horizontal bracket attached to the top, back of the speedometer. If it's not... there's your first problem. The stabilizer will look like a little metal box about half the size of a "normal" thumb. It will have a circuit board on one side and the circuit board will have some spade lugs poking out with green wires attached. The voltage stabilizer MUST have a good electrical earth/ground through its case. If it doesn't, it will pass full charging system voltage to the gauges. This will make them read as much as 40% high.

So, first find the stabilizer, then remove it and clean up its mounting surfaces. Consider running a dedicated earth/ground wire from the mounting screw of the stabilizer to a good, clean, metal earthing point somewhere nearby.

If you don't find the stabilizer, try getting a decent photograph of the back of your speedometer (from the engine compartment) and upload the picture when you post your reply. Regardless, post back with your findings.