Series 2 ongoing fuel tank problem

listed this a while ago and didn't really get an answer to the problem, so here goes again, 1962 series 2a fuel gauge just goes straight to full even when the wire to fuel tank is disconnected, i have swapped the gauge and today swapped the tank sender, still the same, its driving me barmy how can something so simple do your head in, does anybody know wether this model has a voltage stabliser ? getting desperate now, close to putting a big hammer to it, would really welcome any suggestions.

Have you tried taking the wire off the back of the gauge and running a new wire directly to it as it sounds like the existing wire is grounding out somewhere

Sorry I just re-read you question so ignore that....It's not something soft like you've connected the wire to the wrong terminal??

tried a new wire, to eliminate that marmaduke, and if its on the wrong teminal it goes to empty allthough its allready on empty, but its got to be something soft and i am not seeing it

peter8315 said:

tried a new wire, to eliminate that marmaduke, and if its on the wrong teminal it goes to empty allthough its allready on empty, but its got to be something soft and i am not seeing it

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Don't know for sure but I suspect it would have a stabiliser.
Is it neg earth?

no positive

sorry no its negative earth

peter8315 said:

sorry no its negative earth

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Might get shot down here and I'm just trying to help .
The gauge has pos to one side and neg to the other side. The neg is what goes to the sender, the negative circuit is completed by going through the sender windings then to the other connection/terminal on the sender plate which goes to a good earth, usually the chassis.
The needle on the gauge moves according to how 'strong' the earth circuit is (resistance).
If the wire to the sender from the gauge is earthing somewhere before it gets to the sender it will get a strong earth circuit and the gauge will read full even if you disconnected it from the sender.
Does that make sense?

Although my reply only applies if the wire you say you disconnected was from the sender end.
You ran a new cable? From where to where?

yes i agree with the theory, but i have ran a new wire from gauge to sender, and same problem happens, Flossie, one thing i havn't done is earthed the sender from the second terminal, do you think that could be the problem, if it is you are a star, ill try it tomorrow

Oi oi oi I suggested that in the third post.

peter8315 said:

yes i agree with the theory, but i have ran a new wire from gauge to sender, and same problem happens, Flossie, one thing i havn't done is earthed the sender from the second terminal, do you think that could be the problem, if it is you are a star, ill try it tomorrow

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I doubt it tbh, the gauge shouldn't move if the neg circuit isn't completed although it could be completed via the screws or whatever holds the sender in, then via the tank itself and to the chassis its bolted to.
What I would do...
( I've never fiddled with a series and I only know enough about electrickery to get me into trouble)
Disconnect the gaugearth
Check what voltage you are getting on the positive wire feeding the gauge and compere with what it's supposed to be (maybe 10volts? If its got a stabiliser?)
Use another earth for this check NOT the disconnected one off the gauge.
If the pos supply checks out OK, reconnect it to the gauge and run a wire from the neg side of the gauge to the sender, don't connect it yet. Remove the sender and check you haven't fitted it upside down? If it fits in the side?
That's OK?
The sender will have a terminal that goes to the float windings and this is the one that the gauge connects to, the other terminal , if you examinate it, should just be screwed, soldered or whatever to the sender plate, this terminal goes to a good earth(to the battery if you like for testing purposes)
You can move the float up and down by hand to see what happens to the gauge.
If you want to play around, pull wire off sender gauge goes empty, touch the same wire to the terminal going to the battery- gauge reads full.

It is the right age to have a voltage stabiliser!!

i am sure i checked the voltage some time ago and recall it being 12 volts, this was all working fine when i bought it, i have done a lot of body work and changed the engine, but didn't have to mess with the wiring to much, its only since i have it all back together that the problem has ocurred, ill check the voltage reading again tomorrow and do the tests as you describe, if there is a voltage regulater were is it situated? according to the haynes manual there is no sign of a stableiser in the circuit, ill let you know tomorrow, and thanks a lot for your help.

peter8315 said:

i am sure i checked the voltage some time ago and recall it being 12 volts, this was all working fine when i bought it, i have done a lot of body work and changed the engine, but didn't have to mess with the wiring to much, its only since i have it all back together that the problem has ocurred, ill check the voltage reading again tomorrow and do the tests as you describe, if there is a voltage regulater were is it situated? according to the haynes manual there is no sign of a stableiser in the circuit, ill let you know tomorrow, and thanks a lot for your help.

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Like I said, never fiddled with a series but on other owd cars I've fiddled with the stabiliser has been screwed to the back of the speedo. Trace the wire back from the gauge and see if it connects to a small box shaped do dah.
Does the sender fit in the side?

Marmaduke said:

Oi oi oi I suggested that in the third post.

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Feck off! The glory shall be mine!
MINE! I TELLS YA!!

The sender is on top of the tank, have,t had time to check your idea flossie be Monday now I'll get back to you on the findings