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MG MGA - fuel gauge problem. Still!

I had my Jaeger fuel gauge rebuilt by Nissenger and after 2 years and many suggestions from this site it I still do not have a functioning gauge. I finally got something to happen however …it pegged at full after playing around with grounds. So in my last attempt to rule out the gauge as the problem I am thinking about hooking up an old MGB Smith gauge. My question: if my MGA is a positive ground and likely the Smith gauge came out of a negative ground MGB will I fry the gauge or the A’s wiring harness… or maybe it will work?

thank you for any ideas
danny jacob

Danny,

I "believe" the early MGB's (62-64) used Jaeger gauges also and are interchangable. But---have you removed the sender unit from the tank. If Nisonger rebuilt it and you get it to move "playing" with ground, its likely not the problem. The problem is in the tank.

Paul
Paul Hanley

Danny

Suggest you check the sender unit.
Initially check the wire connection is at the bottom. If not it's upside down like mine was when I got my MGA. Gives a full reading all the time that way up.
Check both the tank and sender unit are earthed.
If all that looks OK, get it off the tank and check you are getting a max resistance on a meter of 70 ohms from terminal to casing and a smooth change to zero as the wiper moves over the coil.
If no connection apparent, remove the little cover and check the wire going from the coil to the terminal has not broken.
If that's broken, things get very tricky, but I managed it. Don't be tempted to solder the broken wire to the top of the coil. it shorts out some coils and ruins the calibration. Been there too!
Hope this helps.

Pete
Pete Tipping

I have some pictures of the sender apart:

http://home.comcast.net/~eastmanb1/MG/MGA_pump/mgapumprepair1.htm

MGA's use "battle magnets" in the gauge. Later B's use a heating element and bimetallic strip. MGA's will read empty with a short and full with an open circuit. B's will read empty with an open, full when shorted.

You can recalibrate the gauge by moving the magnets. I think Barney has a write-up.

Bill
Bill Eastman

A gauges are easy to burn out if you get the wiring wrong....

Then they always read full......

dominic clancy

The adjustment of the magnets should also be done VERY carefully! Don't make the nuts too loose or you will break the guage. Barney has a good test for the system and I would suggest you carry out the grounding tests as he suggests first.

My fuel guage used to be the sound of the fuel pump clicking telling me I was out of fuel.............then I repaired the guage!
Ian Pearl

This thread was discussed between 03/06/2006 and 12/06/2006

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