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Low reading guages

Posted: Wed Jan 10, 2018 8:02 pm
by aidanfisher
When I bought OME 87L both the temp gauge and the fuel tank gauge were reading something like less than half they should.

I changed the temp sender--no difference. Today I changed the voltage stabiliser--still reading the same.

Any suggestions as where to go now?? Help!

Re: Low reading guages

Posted: Wed Jan 10, 2018 8:42 pm
by Dave B
Try an additional earth with good clean contacts to the (black wire) negative circuit at the rear of the instrument panel.

By the way, dont forget the Lancashire group meeting a fortnight tomorrow 25/1/18. :)
New Hall Tavern, Cuerdale Lane, Samlesbury, Preston PR5 0XA.
01772 877942

Re: Low reading guages

Posted: Thu Jan 11, 2018 3:48 am
by tony
When I had this problem a few years ago I found the earth terminal had dropped off the back of the speedo.

Re: Low reading guages

Posted: Thu Jan 11, 2018 1:35 pm
by aidanfisher
Just tried an new earth wire --back of speedo to body panel --just the same result!!

So now need to do some serious digging--snag is its b--y cold working out there!

Haven't forgotten about the 25th!

Re: Low reading guages

Posted: Fri Jan 12, 2018 5:24 pm
by Mike Stevens
I guess you need to measure the voltage coming out of the regulator. If it's an original mechanical type it should wander about a bit but average to 10V ish. I think you've fitted a new one so that will (probably) be electronic so a steady 10V. Anything less than this is a fault as is much above 10V too!

As your gauges (temp and fuel) are reading low I'd expect the regulator output to be low. If it is, try disconnecting one or other (or both) leads from the regulator to the gauges. Maybe there's a fault in one which is pulling the 10V line down. Hopefully this will help you fault find!

Good luck,


Re: Low reading guages

Posted: Sat Jan 13, 2018 12:05 pm
by Alec
Hello Aidan,

if your voltage stabiliser is the original bimetal type, ensure that the case is properly earthed also. However as Mike says, if you can do a voltage check that will be very useful. (Analogue meters are better for the bimetal type.)


Re: Low reading guages

Posted: Fri Jan 19, 2018 8:48 pm
by aidanfisher
Thanks for all the advice chaps--jobs on hold until this perishing weather lets up a bit. I have a trusty AVO meter so should be able to get some sensible readings.
Wish me luck!