Symptoms of the car. After driving a while the car start to run rough and the charcoal canister at the rf wheel begins to leak fuel. I pulled the canister and the car runs perfectly fine. The line that goes into the place marked T on the canister is the one that I think goes back to the fuel tanks via a T. This one was also dripping gas after I drove the car without a canister on it.
I am working on a 1976 series 2 XJ6 and all I have is a series 3 manual.
I think the canisters, and plumbing are the same for series 2 and 3 but someone is welcome to correct me.
The fuel delivery is controlled by the fuel pumps in each of the tanks and both pumps seem to be working correctly.
I think on a series 2 there is a fuel solenoid valve for switching between the tanks, but I don’t know where it is?
How do you get to and check the vapour separators that reside in the C pillars?
What other test should I perform, or suggestions on fixes?
Oh gosh, i just came across this exact phenomena and explanation in passing recently wishing to add to my memory bank of useless information…but of course forget anyway.
I will search, but perhaps i think it has to do with a clogged gas tank vent tube drain and pressurized gas tank forcing fuel into charcoal canister…of course thereby ruining canister contents.
Do you experience a vacuum wooshing sound when opening gas cap?
Anyway, lemme search…damnit.
PS: Don’t overfill gas tank.
People continue click clicking when the pump stops to fill it to " tippy top " … and that will flood them too apparently via vent line.
May only be this.
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It’s a messy topic, with variations, Kevin - differences in layout and symptoms between carbs and FI. So what do you have…?
Assuming carbs; in your case, fuel is delivered via the tank venting system to the carbs - causing overfuelling, and the engine misbehaves.
The usual cause for pure fuel to the canister is overflowing tanks.
In EI, with a single pump; the fault is either with the fuel return or changeover valves - causing fuel to be returned to the ‘wrong’ tank, which overflows. The engine does not react - but the tank visually overflows, and fuel is reaching the canister via the fuel separators. Remedial actions is attending to the valves…
With dual submerged pumps; only one pump is running according to selection, and the access to the the other tank is blocked - preventing the pump in use pumping to the other tank. Check this function - while disconnecting the canister will remedy engine running, but it will not cure the actual problem.
As Demian says; liquid fuel in the canister ruins the charcoal - either the canister or its charcoal must be changed. After remedial actions to eliminate crossflow.
It is very important that the gas tanks are vented. The closed ventilation system is an emission control device - ‘Europeans’ just vents to open air. But both are equally vulnerable to tank ‘crossfeeding’…
The car is a carb car, and it does have a fuel pump for both sides. From what I am reading from Frank the pump that is off prevents the fuel from feeding back into that tank. Is that correct and there is no change over valve on a series 2 with carbs?
I don’t know if I am getting a vacuum in the tanks. You have to drive the car for about 30 minutes to make the overflow happen, and I don’t think this is long enough to cause the vacuum issue if there is one.
Questions -
How do you get to the fuel vapor seperators which I think are located in the C pillar area.
I am going to drive it today and do a few experiments. One I am going to leave the fuel doors loose so that it vents that way and see what happens.
Two I have been Using the LS tank and I am going to switch to the RS tank to see If I can get it to do the same thing or will it operate normally.
Any other suggestions are welcome.
oh and venting to atmosphere is another option that I will consider.
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That’s a proper test for any fuelling anomaly, Kevin - with EI the system works normally in one selection. And it may be the same with the carb set-up…?
I ‘think’ the one-way valving is is incorporated in the pumps, not external - but it may vary with pump type?