Hello i'm having a weird problem with my fuel gauge.

It seems that when i turn the car on the fuel gauge move's along to what i think is about right but when i'm driving it starts going down, then when i stop at say some traffic lights it starts to rise again?

I have a spare voltage reg that i've tried swapping over and get the same result.
Its a round nose center speedo type.

Anyone have any ideas?

Thanks for the help

Alternator has issue i would say. You are getting voltage drop when you drive.

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Good call i didn't think of that. I'll check that out. Thank you.

I would be interested in your findings as I have a 73 mini van which has the same problem.

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1969 Cooper "S"
1967 Mini Deluxe
1973 Clubman Van (the fleet spare)
1978 ex 1275 LS ("Wizard" Eaton Supercharged)
2015 HSV GenF GTS(occasional drive & tow car)
2019 MINI F55 Cooper S

Mine's doing the same thing at the moment -- fuel gauge goes up, fuel gauge goes down.

I'm replacing the alternator next week, as mine is on the way out.. I'll let you know if the problem goes away.

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Simon

The adventures of an owner builder in the Tallarook Ranges

My fuel gauge goes down as I drive as well, however it doesn't go back up until I fill it.

Mine did that for years. The faster I went the lower it read. Then you stop, and watch it come up....
But I could put it up on stands in the garage and run it at 50 or 60mph and it never went down. Had me stumped, until...

I decided to try a new 10V electronic voltage stabilizer, as I had one of Wombat's here.
IT FIXED IT.
It seems the problem was that the old ones are a vibrator similar to a blinker can- road vibration under way reduces the output voltage when they get old. So the gauge reads lower with speed.
So I flung the old one far, far away.

PM Wombat for a new one, I bet it fixes it.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

i keep hearing about wombat's fancy voltage stabilizers, i think i'll give it a try i'm a bit curious.

PM'd wombat, i'll post the results.

thanks for the help.