84 xj6 series 3 fuel guage doez not work

The guage will not work for either tank and it actually reads below empty. Is there a fuse or some kind of voltage regulator. Thanks in advance

Check fuse #4, George - but a blown fuse should also kill the temp gaugeā€¦

Frank
xj6 85 Sov Europe (UK/NZ)
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If not, remove a taillight and short the wires to the sender behind. See if the gauge rises when the tank is selected, in that case switch, wiring and gauge are good.

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good to know.
Iā€™ve got an '86 with a bottomless tank. one guage doesnā€™t go above 1/8 of a tank and the other never drops below 1/4 of a tank. So Iā€™ve always got petrolā€¦ Right? :smile:
good trick about the tail light. when or if I ever get there, Iā€™ll give that a go.

Cheers!
Mark

Itā€™s so easy I must have done it at least five times. 7 screws and youā€™re there. Should you want to look at the Senders make sure that you really are below Ā¼ and get gaskets. The senders can be inspected and, to a degree, repaired as well.

This trick is also very cool because it gives you a full tank instead of Ā¼ :relieved:ā€¦ whatā€™s not to like about that.

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flash backs when I discovered my Series II had a hole in the left tank. Itā€™s a nice summer day enjoying the weather and my SWB Series II. People waving, Iā€™m waving backā€¦ Iā€™m thinking it usually doesnā€™t take this long to fill the this tankā€¦ The gas smell is really strong todayā€¦ why does it sound like itā€™s rainingā€¦ why is my foot wetā€¦ OH SH T
end of story.

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Nobody told me my changeover valve had been drilled out by a PO and I was losing half a tank of fuel while driving around.
People werenā€™t waving on that cold winter day and if they did, yes I would have been VERY worried.
George: the switch changing tank selection does not mean that it also switches the other circuit. If one side doesnā€™t go up then short the other too. (The gauge just measures voltage, it wonā€™t harm it). Before, do check and change the fuse because they can look very good yetā€¦

Ironically, I just replaced the left fuel sender in my restored 1985 XJ6VP. I ordered the sender from EBay and was only $21.00 plus shipping. The new sender was made in the UK and seems to be OEM. Before installing, I tested it. When moving the lever on the sender to full, it only registered 3/4 full. Thinking it was a faulty gauge, I tested the gauge by connecting the wires together. It read full. I thought the sender was likely faulty until I decided to bend the metal tab in which the lever would rest on toward full. The lever could then move a fraction beyond the tab which resulted in showing full on the gauge. I wonder if the tab was not aligned perfectly on this one or if itā€™s a manufacturing error?

Richard


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Whatever, Richard; the usual way of ā€˜adjustingā€™ gauge reading is to bend the arm itself. But if the tab restricts movement as described - itā€™s presumably not intendedā€¦

However, as fuel level decides the float position, correct gauge reading can only be verified in-tankā€¦?

Frank
xj6 85 Sov Europe (UK/NZ)
**

$21 for a new one, not bad. I assume the best way to compare senders is to put old and new side by side and compare the travel. The rest is determined by the wound resistor wire inside the senderā€¦

Indeed, the tab is there to limit the armā€™s travel, but can be slightly adjusted but should not be deleted.
Nevertheless, the arm is not attached to itā€™s bronze axe rigidly and can also be adjusted.
It took me for ever to calibrate both senders to read the same and read true ā€œemptyā€ and true ā€œfullā€.
A long, smelly and arduous process.

A recent misadventure with my jeep improved my knowledge as to just how fuel level sensor work.
It was my Jeep. It uses a module. a device that is a container for the rheostat and the fuel pump! In the case of the jeep the sensor just plumb wore out, It showed that the tank retained abut 1 1/4 tank, when in fact it was empty!!! Guess why the jeep quit running and came home on a flat bed.

The stationary part has windings. The arm sweeps those windings. The windings are resistance. .More ohms on one end than the other! The rheostat completes the ground leg of the guage circuit. Variable ground,.Teh guage reads in that manner. So jump the rheostat to ground. the guage will jump to full!! Or is it jump to empty, In any event it demonstrates how the circuit works.

I thnk most are adjusted t the factory to read empty yet retain. couple of gallons or soā€¦

Carl

maybe one day my XJ will look so beautiful.

Seems like both sides are reading below e i do know that i need an alternator but would that affect fuel guage

No it will not.
The gauges are designed so that voltage fluctuations donā€™t alter their readings.
They both read low because your floats are full of fuel. They will need to be changed. I am sure you could find new ones, Ford makes ones that are the same dimensions, details on Kirberā€™s book.
As mentioned before, they are easily accessible, but the tanks should be bellow 1/3.
Once the senders are out make sure that when the arm is up the gauge reads full and vice versa.

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The good news, theyā€™re keyed and will only go in one way. Get the gasket for each.
Draining the float and ā€˜solderingā€™ the plastic shut did not work long for me. Left and right sender are different.

It would be ofcourse prudent to get new gaskets, but mine were in good shape and I reused them with no problem.

I did the same despite a few cracks and it started to leak after a year - and thereā€™s the risk of tearing it, so Iā€™d be happy if someone suggested I get those before destroying them in the process. I reuse most gaskets but these are in my opinion worth changing.

There are plastic ā€˜barrelā€™ shaped floats in the arm that will absorb gas over the years. If you can get one or two before you take the senders out, it will speed things up if you find a problem with one or both of yours. They are hard to find separate from the senders, but keep your eyes out for one. I had to replace both of mine.

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One possibility with hollow plastic floats is to drill a small hole in the floats, Kassaq - draining off the fuel and reseal with a hot ironā€¦

The set-up is not sophisticated - anything that floats and is impervious to petrol will doā€¦?

Frank
xj6 85 Sov Europe (UK/NZ)
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