Cleaning the in-tank filters in the XJ is very easy Kirbert, except from having to empty the tanks, it’s just a matter of undoing the big drain tap at the bottom of the tank, easily accessible from provided holes at the side covers.
I just checked them a month ago and they where sparkly clean, and last time before that was 10 years ago, but my tanks are in very good shape.
You have a point about the combined resistance though, I once had problems with an aftermarket pump cavitating, it could very well be the fact that I had both filters.
Now with my new Turbine type Bosch pump I don’t seam to have a problem but I’ve noticed that the engine needs a couple of turns more to start than before. Could this be the reason?
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Did you actually check the valve function before drilling, Felix?
There should be nothing going through the valve unless tank pressure is above 1,5 psi (petrol heating up while standing) - or tank vacuum below 1,5 psi (engine using petrol).
Incidentally; the tanks commute via the vent lines - tanks are at the same pressure/vacuum…
Frank
xj6 85 Sov Europe (UK/NZ)
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Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
23
It’s not too difficult to clean the pickup screen in the XJ-S, too, but that’s not the point. The point is to get crud out of the tank. If the saloons behave anything like the XJ-S, the minute you turn the ignition off the crud falls off the screen and back to the bottom of the tank. Then you can clean the screen all you want, the crud remains in the tank. As soon as you start the car again, that crud resumes collecting on the screen.
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
24
Perhaps the turbine pump needs a couple of seconds to get up to speed?
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With the two-tank system, Kirbert - that happens when you switch over tanks. Hence the simple test of switching tanks as the engine falters - if the engine instantly recovers; it sure is a symptom of clogged in-tank filter…
I put 1/2 litre of metho down each tank just to get rid of any water that might be in the system.
Then I went back to the charcoal canister and left the vent valve for the tanks that I drilled out fitted,and is now venting out through the canister.
I removed the purge valve vacuum hose from the throttle body and blanked that outlet,I also blanked the purge line that goes into the breather pipe.
Timing was still right at 4 deg BTDC but I had to adjust the allen screw to drop the idle speed from 900 down to 800 RPM.
Now the engine is running as smooth as silk.
So I must have had 2 problems,the fuel tanks were dirty and the charcoal canister system.
All I need now is to replace the fuel filter again next week.
Thanks for your help guys.
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Just to emphasize; the important thing is that the tanks must be ‘vented in’ - through the canister or whatever. Without venting; vacuum will build up in the tanks as petrol is used - and eventually collapse the tanks. While pressure may build in the tanks as fuel heats and expands is less of concern - they’ll stand pressure better…
It is just a comment to accentuate ‘vent in’ as a prime concern! You are good to go, but ensure that air can enter through, or past, the charcoal - or the tanks may implode…
At the moment if I blow through the vent tube in the wheel arch,air is going straight through the canister and out the top of canister into engine bay area.So does that mean the tank is vented.
Now when I open the fuel tank filler caps I do not get any pressure noises.
I think the canister is passed its use by date.
Regards Felix
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
31
Those canisters will work nearly forever, although it is supposedly possible to poison them with fuel additives. But they’ll vent the tank forever. The problem is that you can easily saturate them so they will no longer soak up any hydrocarbons, resulting in the car smelling of fuel. And saturation is exactly what the 2psi valve is designed to prevent. If that’s what you drilled out, I’d expect the car to stink.
I will take the car out for a drive this weekend and see how it goes and report back,hopefully there will be no fuel smell.
Meanwhile I will chase up some valves for this canister and return it back to normal.
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Renewing the charcoal is a scheduled maintenance item, Felix - the charcoal gets ‘tired’ over time, loosing it adsorbent qualities. And as Kirbert says; liquid fuel poisons the charcoal, an petrol vapour will leak out and may smell…
Another factor is that the charcoal may solidify and block the tank venting - but since you can blow through, you are good to go…
I took the car out last night and filled the fuel tanks.Drove it for a while and she ran like a brand new car.No fuel smell evident.
So the car had 2 problems,dirty fuel tanks and the charcoal canister not functioning correctly.
