Fuel gauge shows ½ when the tank is full

[leafie]

My fuel gauge shows ½ when the tank is full, by taking the wire off the sender and connected it to earth I get a ¾ full reading. Has anybody got an idea as to the most likely culprit for this fault?

Thanks

Leafie

[Rob_Jennings]

either the gauge is failing, or the 10v regulator behind the speedo is not working correctly. If you have access to a multi meter check for 10 volts there.

[leafie]

either the gauge is failing, or the 10v regulator behind the speedo is not working correctly. If you have access to a multi meter check for 10 volts there.

Thanks Rob,

I have taken the speedo out. Is the regulator the small rectangular box bolted to the back of the speedo with 3 wires (1 to the gauge) if so the readings are all over the shop from 0.4 to 9 and do not settle. am I looking at the right area.

Thanks,

Leafie

[Rob_Jennings]

yes thats the right place. light green wire is the 10v output and goes to the fuel meter.

The regulator is a thermo-mechanical device (works a bit like the indicator flasher, turns on heats up turns off as output reaches about 10v) the gauge is heavily damped to account for the turn on/off cycles. if the output never reaches 10v and is very unstable then it might be on the way out.

you can test the gauge by finding a 10v 'ish supply eg series of 7 batteries will reach 10.5v and will a good give full scale or a 9v battery out of a smoke detector should give near full scale.

[leafie]

a 9v battery out of a smoke detector should give near full scale.

Thanks for the info Rob, tried the 9v battery test and sure enough the fuel gauge reads almost full. So the regulator is the likely fault, are they easy to get hold of ?

Thanks,

Leafie

[Packedup]

Far more electronomagikally minded than me know how to fit an electronic type for under a quid.

I personally thing the more expensive but easier route looks like the Mini one - Same output/ input, fits on the back of a Mini speedo (same size as a Minor). Not had to do it myself, but can't see any reason why it wouldn't work

[Rob_Jennings]

I put this page together on how to fit a solid state one.... only applies to negative earth cars.

http://www.robjennings.plus.com/morris/ ... e_reg.html

you will need a solder iron and very basic skills

otherwise as said the mini one is identical in function or most suppliers should be able to source the minor one.

[Packedup]

I put this page together on how to fit a solid state one.... only applies to negative earth cars.

http://www.robjennings.plus.com/morris/ ... e_reg.html

you will need a solder iron and very basic skills

Excellent info

Though I lack a soldering iron, and don't have much in the way ofbasic skills, but with that page to hand i might have a go at it some time

[leafie]

I put this page together on how to fit a solid state one.... only applies to negative earth cars.

http://www.robjennings.plus.com/morris/ ... e_reg.html

you will need a solder iron and very basic skills

OK going for it, purchased regulator from Maplin for the princely sum of 59p. Will have a go at soldering the wires on and fitting this week. Never soldered anything in my life so I hope Greater Manchester Fire Brigade are on the ball.

Leafie

[leafie]

I put this page together on how to fit a solid state one.... only applies to negative earth cars.

http://www.robjennings.plus.com/morris/ ... e_reg.html

you will need a solder iron and very basic skills

Thanks Rob,

Job done, and for only 59p.

Leafie

[DaveC]

Same problem. Same solution. Well happy!

Thanks Rob