Fuel gauge

[paul w]

The Grinnalls fuel gauge does not register the level.I have removed
the instrument pod to change some bulbs and plugged it into my autos
loom.The gauges/bulbs all work ok.I had a pleasant suprise as i
crawled under the rear axle to find a new fuel tank fitted,and it looks
like a new sender too.Whats the best way to check the feed on the loom?
Will i need to remove the sender to check it anyway?

See ya. Paul

[ngtf]

Hi Paul

In an attempt to try and help; there should be continuity between the Green/Black wire at the gauge end and the Green/Black at the tank. It is also important that the tanks earth is good, certainly worth checking.

Has the gauge ever worked (Could the sender be incorrectly wired)?

Does the "Low Fuel" light work?

Cheers

Gary

Eeyore rides again !!

EOR14W - Persian Aqua 2L Dhc, Now rebuilt and looking lovely - Sprint engine now fitted!

[PeterTR7V8]

I found that when my gauge stopped working it was a loose connection at the sender. There should be 3 wires at the sender. I assume 1 is 12V & the others are the returns for the gauge & the warning light. When my gauge failed the warning light still worked.

If I were you I'd get under the car with a volt meter & check that the sender is getting 12V & that the connections are sound. I'm not a sparky but I think the gauge return wire should show 12V as well if it is working as it is just the current that gets reduced by the rheostat in the sender unit.

If there is 12V going thru the sender & it still isn't working drain the fuel & take the sender out to make sure the float isn't stuck. If 12V isn't going thru then it is probably a broken wire & you will need to take the sender out for repair or replacement.

If that doesn't work then - well, god only knows & I bet he's not telling.

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[Odd]

Paul,
I'd drain the tank and take the sender unit out. I bet you have a sunken float (filled with petrol).
The curled up end of the wire holding the float ends in a sharp edged cut - that should be bent
away from the floats but it isn't, so after a while the end of the wire holes the float. Very little,
but enough to let the fluid seep in.
New floats can be bought from Jaguar, they are part number JLM772
/Odd

[jclay (RIP 2018)]

Three wires,

One is ground = Black
Green/Orange = Low fuel light
Green/Black = Feed from Gauge.

As the float descends in the tank, the resistances increases and the gauge reads this and responds accordingly. <i>(So you can see that any corrosion on the connectors and at the ground wire to the frame will cause resistances and give a lower reading at the gauge!)</i>

When the level of the fuel gets really low, the Green/Orange makes a connection which then does to a delay circuit (keeps the light from flickering when the fuel slouches around in the tank) and then lights the low fuel light.

jclay

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[paul w]

Thanks for all the advise and info.Turns out the connections at the
sender unit were dirty.A bit of a clean and the sender started to
behave itself.Unfortunately the low fuel light now works,but even tho'
the tank is full.It flickers on and off annoyingly.Any way it was a
good excuse to test drive the wedge again as the sun came out after
all that rain we had.I 'aint kiddin',we had floods round here!!


See ya. Paul