excuse me for being to lazy if I am wrong, but as I recall the fuel pump pulls fuel from the tank and strainer and then pushes it through the filter to the rail.

Is it just me or is that stupid? Again, maybe I am remembering incorrectly, but I feel that is how it is setup. If so is there any reason I can't change the order??

My tank is pretty dirty and ruined my old pump and its having a bad affect on my new one. If I get another pump and filter I would like to swap places so if the filter gets clogged it can just be replaced instead of replacing the filter plus the pump!

sorry If i have this wrong, but a couple of cents would be of help!

 

Most modern cars are set up that way, with the pump in the fuel tank and the filter further up along the frame rail. On the XJS, I think you can install a more coarse filter before the pump and leave the fine particle filter after.

 

The fuel pump on a pre-facelift V12 or 6 cylinder car is gravity fed from the main tank, to a sump tank with a mid-sump-tank supended fine sock filter covering the further gravity fed outlet to the pump. All with wide diameter hoses. If the sump tank is cleaned and the sock filter regularly renewed, the pump will not be harmed by debris, regardless of the main tank's state.

If you are really worried, place a 1/2 inch diameter non-EFI fuel filter between the main tank and the sump tank, but the effect of this extra filter is no more than a properly functioning standard system.

An EFI filter before the pump will starve the pump of fuel (these pumps do not suck) and ruin both the pump and the driveability of the car as the rail will get starved of fuel as soon as you accelerate.

Greg

 

I have all of the carpet out of the trunk and am getting ready to replace the fuel filter and all of the hoses.

I am toying with the idea of adding another filter and just eliminating the surge tank to simplify the system. It seems this would do away with a few hoses and connections and leave fewer places for seeping.

I believe I read on here, maybe a Grant Francis post, that there aren't any ill effects. Am I missing something? Isn't simpler usually better? Just want to make sure I'm not overlooking anything.

Very open to thoughts, suggestions and recommendations.

 

As long as you find a non-EFI filter with at least a 1/2 inch inlet and outlet, this idea will work. However the sump tank's real purpose (aside from providing a filter to protect the pump) is to provide a mini-fuel tank that will NOT run dry on hard cornering. If you do away with the sump tank, with a low level of fuel in the main tank, and on a longish sweeping bend, you will run a serious risk of low fuel pressure/and or running the pump dry and ruining it. Two gallons of fuel (at about which point the low fuel light comes on) is less than 2 inches in the tank, remember.

As the new filter will need to be changed at least as often as the sump tank filter, unless you fit racing-style dry-break couplings each side, there is not really any maintenance advantage, as you will need to leave the sump tank in place (without a sock filter) or to fit a custom made pre-pump fuel collector - I believe called a swirl pot in the trade.

I know there are those that believe the standard engine cooling system cannot be improved upon (NOT me); well, I am one of those that believe the standard fuel delivery system (as far as the tank/pump/filter setup is concerned) cannot be without having an entirely new setup including the main tank!

Greg

 

the pre-facelift doesn't have a sock filter, does it? All I have seen is the screen on the smaller tank and its really pretty course

 

The sump tank has a outlet pipe to the pump which is secured by a locking ring and sealed by a rubber gasket. Inside this locking ring the pipe pokes into the tank and this pipe should have a 'sock filter' over its end. This looks like a round tubular plastic cage-type item which is covered in a fairly fine mesh.

Greg

 

Depends where you live as to what it is called.

The plastic fine mesh filter Greg refers to is fine enough to trap water, so I reckon coarse is a little harsh here.

 

As fo removing the sump tank, YES, anything is possible.

I did one a loooooong time ago. It was a PreHE, and the sump tank was rusted out, but the main tank had been replaced.

It was HIS suggestion, NOT mine.

The fuel pump ended up where the sump was, and the HI pressure line went directly to the brass elbow out of the floor. The fuel filter was relocated to the engine bay, just below the RH headlamp bowl. A small 1/2" in/out Wix filter was installed in the line from the main tank to the pump.

He kept the fuel tank 1/2 full at all times and never had an issue with it.

 

Thanks for the responses.

It appears that the stock set up is simpler in the long run. I spend too much time watching the temp gauge to have to watch the fuel gauge too. Looks like I'll be leaving things as they are when I change the hoses and filter. I'll check the surge tank for crud and make sure things are clean.