XJ6 S1 fuel tank venting

Hi, I have an early S1 with the usual water/fuel contamination issues. Have therefore removed left side tank (original S1 tank, while right side tank seems to be S2) to connect new drainage-hoses. While removing left side tank I found couple of things I would be happy for insights on

Image 1 & 2 (luggage compartment - below rear window)

A= hose connected to the left side of the unit “B” and ends up other end (it seems) with an outlet into rear wheel arch
B= what is this unit? Is it related to fuel evaporation/venting system?
C= hose connected to right side of B-unit. This hose was only approx 30cm long as was cut in mid air (and stuffed in behind the luggage compartment side wall)
Image 3 (left side tank)
D=what is this - currently plugged- outlet from tank (maybe from earlier workshop tank replacement)

  1. What is the unit marked “B” (and its function)?
  2. How should hoses be connected to B (and to left & right fuel tanks)?



Can only help with a photo of the hoses from the Jag CD.

Hose from inside to the fuel filler cap is important and hard to get back on the cap… must be a tight fit at the cap and be the correct original size…hard to find size today.except at foreign car parts stores.

The hose from the top of the tank is shown in the second photo.

My S1 has S3 tanks now due to the need for the return lines for fuel injection… hoses are different.

Sorry for the extra photo of me and my dog… editing software picked it up…

Not related, but ask Cortana for the snipping tool. (click on the windows button (lower left) type snip and Cortana should caugh up the Windows Snipping Tool. I find it very useful for capturing just what you want.

Like the picture of you and your 4 legged friend :slight_smile:


Before going any further, Fatboy, I think it is relevant to clarify some points - a PO may have made some confusing modifications…?

I assume you have carbs - which do not need fuel return, while the S2 and later tanks may have the fuel return tank connection, serving no purpose with carbs. Check if the charcoal canister is fitted and connected up, verifying that you have closed tank venting system - which makes a difference. There are no fuel evaporation/venting system components in the boot, but fuel separators would be in place in the C-pillars - with two hose connections to the tanks. I assume further that you have problems with the tank/fuel pump connections…

xj6 85 Sov Europe (UK/NZ)

If I interpret the photos correctly “B” is the pressed steel tray which bolts up under the rear parcel shelf; “A” and “C” are the hoses which drain this - both hoses should terminate at the rear quarter valences near the fuel tank drain plugs. They are part of the cabin ventilation system - nothing to do with fuel.



Thanks for the information…

Roger Mabry

thanks Roger, appreciated, but forgot to say my car is European spec. Have found the same nr 1 photo in my “Series One Parts Catalogues”, but its annotated with “Canada/USA”, so maybe for a later consideration.

Hi Frankie, that sounds about right. “Steel tray” located under rear parcel shelf-accessible from luggage compartment (as shown on my first photos). It would make sense if the hoses should not connect to tanks (as currently seem to be the case), maybe this photo corresponds/not sure image

Thanks Frank Andersen (sounds Scandinavian…, car is European spec-in Norway), nevertheless - carbs, yes - and assume the attached image is the carbn canister (disregard the rusty battery tray).
So what is the thing with fuel separators in C-pillars? Would that be the hose gong from the “D” in image 3?
Tank/fuel pump connections? Not that I am aware, what would those be?


If you are refering to the round canister under the bonnet latch release cable…that looks like your windscreen wiper motor assembly to me.



I’m indeed a Norwegian in exile, Fatboy…:slight_smile:

European cars did not have the closed vent system - though at some stage fuel separators in the C-pillars were fitted to all cars to be connected only in markets that demanded it. The separators just ensures that liquid petrol is returned to the tanks - while and only petrol fumes reach the canister…

On European cars the tank venting was done by connecting a hose to a spigot on the filler neck - reaching down below the chassis.

The canister was not fitted on Europeans - and as Gary implies; the item shown has nothing to do with the fuel lay-out…:slight_smile:

In short; with carbs; you need the connections from tanks to pump(s) and carbs - and the open vent hose. The other connections on the tanks are redundant - but the boot lay-out depend on whether you have in-tank pumps, two pumps in the boot or a single pump with a changeover valve…

xj6 85 Sov Europe (UK/NZ)

Just to clarify further Fatboy, the take off you have marked “D” on the top of the fuel tank is the connection for a hose leading to the carbon canister. This is necessary on Emission control engines for some markets but was not necessary for the early UK market (and possibly others). Therefore for a UK market car the take off was blanked with a rubber bung (similar to what you show in your photo). The system is known as the Fuel Evaporative Loss Control system - fuel vapours from the tank are taken to an absorptive carbon canister via the connection you mark “D” which stores the vapour until it can be disposed of via the engine crankcase emission control system when the engine is running. So, if you have the FELC system you need to make the tank vent connections - otherwise leave them plugged off.


thanks all for good input, highly appreciated - got myseslf some new hoses and ready to put tank back in (and then remove other tank which is a series II from what I can see).

Hi again, both tanks out from my EU-spec XJ6 SI, 2.8l (1969). Next step is acid-treatment of below tank for rust-removal. But first, would again be helped - by confirmation that attached images is a series II-tank (being my right side tank).
1st image is seen down into drain hole where a plastic filter (?) is standing right in hole. Is this a filter, and does it have any function in my series I?
2nd image is seen from fuel sender hole (which is in the aft of tank - right behind rear lights), where same filter can be seen shining bright top of image - connected to a set of tubings (upper right).

I assuming the filter + tubing are of no function in my series I - cannot see that they are connected to anything, and woud like to remove as much as possible before acid treatment.
regards, Fatboy

That looks very similar if not identical to a S1 tank. The plastic filter screen is a friction fit over the pick up pipe. You should remove it by pulling and twisting; it will come out of the drain hole. Replace it after you refit the tank, making sure it is clean, or renewed.

Some leave the filter out, and substitute an inline filter between the tank and the fuel pump. The only problem with it is that if you suspect it is clogged, you must drain the tank to access it. IMHO.

It has the same function on all ‘our’ tanks - filtering out tank debris before entering the pumps…

xj6 85 Sov Europe (UK/NZ)

1 Like

hello and thanks for having me.
im from cape cod in massachusetts,
i have a 1986 xj6 that has a rotten right rear fuel tank . i have let it run dry. then switched to the left with dashboard switch. i have removed the fuel pump valve totaly.i now have fuel pump only on left tand. it run beautifuly,but issue is severe fuel vapors while driving,and no fuel leaking from anywhere.? please where sould i head? to the front charcole canister or the fuel canister in the piller ? i have ripped the rubbers on the fuel filler thinking it may need venting. please advise thank you

Welcome on board, Sam…!

Have you bypassed the changeover valve by connecting the ‘left’ tank hose directly to the fuel pump, Sam…?

The changeover valve, operated by the dashboard switch, just opens the selected tank to the pump. With only one tank in use the valve is redundant, and if connected, may cause complications.

The pump feeds through the non-return valve, then the filter to the fuel rail. Petrol is returned from the pressure regulator to the selected tank by the two fuel return valves - open to the selected tank and closed to the other. This is a separate fuel circuit - and may fail. So check, with the pump running, that there is no fuel delivered back to the ‘right’ tank - which may cause fuel smells from a rotten ‘right’ tank.

And do tape over the switch in the ‘left’ (‘in’) position to prevent accidental operation - which may send petrol to the rotten ‘right’ tank.

Certainly; venting is essential - and the with the US closed venting system; the charcoal canister should be inspected. But lack of venting usually show some symptoms, eliminated by opening the filler lid - which may cause petrol smell…:slight_smile:

However, the venting communicates between tanks via the fuel separators in the C-pillars. If there is a hole in the ‘right’ tank, venting bypasses the charcoal canister…

Fuel smells are elusive, but ripping of the filler lid rubbers is not the answer - reinstall. There may be residual petrol leftover from work done, including in the ‘right’ tank - causing the smell…

A little stray petrol may cause a lot of smell - reinspect…

xj6 85 Sov Europe (UK/NZ)