1974 XJ6 series 2 : fuel delivery issues? ...


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Oct 28, 2011
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Hi all,

So I just purchased a 1974 XJ6 series 2 4.2 litre. She needs some work which I was aware of but I’m already butting heads with the twin tank system and wonder if someone could short-circuit my investigations please? ...

So, opening the boot, I was confronted with this. The 2 tiny things appear to be the fuel pumps which look very different to the SU pumps I was expecting to see.

When I collected the car, the owner demonstrated the twin tanks switchover and the fuel gauge registered 2 different fill levels in each of the switch positions.

Switch “In” – left hand pump can be heard to be operating/whirring away – release the fuel switch to “Out” and the left pump stops and the right pump likewise starts whirring away.

However, with the ignition on but the engine not started, the pumps seem to operate continuously.

I’m used to, in my MK 2, when the fuel pump has pressurised the fuel line and presumably filled the carb float tanks, the fuel pump would slow its ticking and then stop – but on the XJ6, I hear the pumps just continuing to operate (one at a time, depending on the switch position) – does that sound right?

(There’s no petrol leak anywhere – the system appears to be completely sound.)

And then any recommendation on where to look at why the fuel gauge no longer registers different tank fill amounts, when the fuel switch is moved from “In” to “Out” – It worked on Friday but now seems to only reflect the amount that’s in the left tank – whereas the right tank is much fuller – it’s been on a very bumpy gravel road to get her home but I checked the fuses and they seem sound - any suggestions on where to look for the source/s of this problem? …

Many thanks in advance – much appreciated – Deej

(In Cape Town - South Africa)


  • XJ6 fuel pumps.jpg
    XJ6 fuel pumps.jpg
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