Xj6 fuel tank sender units

Hi, my 1971 series 1 Daimler sovereign has two faulty sender units in the fuel tanks. I looked in the workshop manual but not too much information there. I’m assuming the fuel tanks have to be removed to fit new senders. Can anyone confirm this before I start to pull my car apart…
Thanks

No, pull senders out from openings in the rear wheel wells.

As Roger says:

Here is what the sender on the tank looks like:

Just make sure you have something to catch any excess fuel if the tanks are over 1/2 full. Or just drain them from the bottom, good time to check if there’s any water/debris in there.

Mj,

are you sure you have two faulty sensors? I’m just asking as the likelihood of two senders failing simultaneously is low. There might be a failure in the fuel guage or in the wiring or a combined failure of one sensor and the fuel switch as well.

A friend of mine once pulled the sensor from his SI car and I remember it wasn’t trivial to get the shebang tight when refitting the sensor - even with a new seal.

What is the actual failure scenario you encounter?

Good luck

Jochen

75 XJ6L 4.2 auto (UK spec)

Here’s one I prepared earlier. My good spare. I just needs the float to be complete.

l

the resistance of the sender coil should be able to be checked at the connectors.

they can get frozen or go open circuit

I agree with others chance of both going bad at once is not high

I changed out the sender in the RH tank on my series 1 which had gone open circuit. The replacements from SNG are not the same length to the float as the old one and I can’t get the float to not hit something inside the tank so it shows empty for a while when full then suddenly releases and shows full. Then it follows consumption down till the next time it’s empty when refilling it again seems to jam for a while before rising. I assume the float is hitting something inside the tank then breaking free. Does anyone know what shape the float wire needs to be bent to to make it work as it should. I don’t want to take it in and out too often because of sealing. The new seal I put in worked fine but I think if I reuse it several timess it will start to leak.
A photo would be useful.

Ian

I put a string on the float end and ran it to the filler area…then pulled the arm up and down…the new float is probably larger.

Compare and bend arm to same shape as old one but favor the side the float is not hitting. I used new gasket several times with not problems…

Empty reading is the only important one…new senders usually only read 3/4 when full…why?!!
Common problem…should read E with 3 gallons or less on the tank…all you need to test it.

@riv944
I just replaced my right fuel sender on my 1970 XJ6, purchased from XKs unlimited. It looks identical to SNG’s and I suspect they are the same part (mine was from eurospare UK - made in GB). It took a little finesse to get it in right without catching on something at the rear end of the tank, but it seems to work well. However, I haven’t filled the tank to full yet. I’ll report back after a fill up.

@mj11
I’d agree that the chance of both going bad seems unlikely - though not impossible. A little circuit checking should tease that out as others have stated. I’d add that a bad sender in both tanks may just be cracked floats - and it’s worth pulling them before an order since floats are a lot cheaper then 2 senders. If you are draining the tank, you should go ahead and pick up the ‘gas tank seal’ - 26310 - and the aluminum washer for the lower plug. I just replaced both of my tank’s seals and fixed a slow leak that I’d been putting off for a while.

Cheers

I seem to have a similar issue with intermittent catching of my fuel sender. I noticed Welsh has a more OEM style sender. Just thought I would throw this out to the group if someone else is deciding which sender to go with.

I spent an hour the other day trying to get the replacement unit to work. Problem is you can’t see how to bend it to miss the two pipes in the tank and don’t know if it works till all buttoned up and filled with fuel again. My one which was intermittently sticking now sticks on empty permanently. Will have to wait till the tank runs out again after this weekend before I can try again. I looked at the Welsh unit, maybe that’s the answer. It is certainly frustrating using the SNG unit.

Ian

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You may need a dummy arrangement, Ian - that can be manipulated from the outside…? To sort of get a feel for the location of the obstructions - mapping angles and distances?

However, apart from clearing obstructions - to get the correct level reading; some ‘bending’ may be required as well.

While not a high precision item, one would expect it to be delivered ‘ready to play’…?

Frank
xj6 85 SoV Europe (UK/NZ)
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Ian,
Have you contacted SNG about the problems you are having with their sender? Perhaps they can help?

Paul

Thanks for the advice, following Roger’s advice I used a string and after several bending exercises and looking where the float and the wire was marked by the effects of the binding I got it to a shape which would rise and fall with the string pull without apparently binding anywhere. I then fiddled a bit more to get E to read when bottomed and sealed it up again. Have around ten litres in at the moment and it reads just off empty so hopefully when I fill up it will work ok. We’ll see tomorrow when I can get to a garage.
Thanks
again

Ian

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Bending of the arm is the approved way to correct readings, Ian - trial and error…

Nominally, 12/13 litres should read 1/4 tank - but due to the shape of the tank; high precision for all levels is not really expected…

Frank
xj6 85 Sov Europe (UK/NZ)