The pump module is not a simple hollow canister. There is a 'jet-pump' built in to draw fuel from the tank and FILL the plastic pump module. That keeps the pump cool and ensues a steady supply of fuel to the pump inlet. The pump module also has a check valve.

I have a few faulty module tops that just spray fuel into the plastic housing and will only provide 10 or 20 PSI to the fuel rail.

The pump module 'bottoms' are all interchangeable. The early ones have the small strainer sock and the later ones have the larger strainer that sticks out farther.

My bet is that you have a faulty pump module top that is leaking fuel back into the plastic housing as fast as the pump is trying to deliver fuel to the rail.

Look at the little metal cup in the module top underside to see if it is broken or leaking.
Also check the rubber seal where the pump outlet plugs into. They tear and LEAK causing LOW PRESSURE.

The 1988-1990 has the external pump and no plastic module to worry about. The X300 has no plastic module, just the pump and strainer sitting in the tank bottom inside a small steel cylinder open at the top.
The older tank with external pump would fit but I don't know if the X300 (1995-97) would fit in the tank recess area. The EVAP flanges are different as well.

Good luck with the diagnosis.

bob

 

Are you using OE cam cover gaskets or aftermarket? If aftermarket that’s probably the reason. When I was running my ‘92 XJ40 I think the last time I changed a CC gasket was when the head gasket went.

 

This makes sense to me. The little metal/rubber seal was torn but I was in no position to wait to get it replaced. When the first pump when in it wasnt but when I had it apart yesterday it was. I worked it back in but this is starting to add up.

I also gather from what Ive seen is this part is not available by itself. Hopefully I am wrong.

Im thinking I should be able to limp the car home and then do a few more checks. If any one has a source for those internal seals that would be helpful.

 

Jeh - Check out Jim's [manwich66] remedy for fuel pump canister issues - I know for a fact that his fix is still working fine in Cin's daily driver (Champ)!

https://www.jaguarforums.com/forum/x...p-died-125377/

might be an option if you can't get the parts ...

ATB

Larry

 

https://www.jaguarforums.com/forum/x...p-died-125377/

If I did not have several old modules to mix-and-match parts I would modify the the pump module like the one 'manwich66' did. (I saved all the old pump modules from the cars I repaired when I worked at the dealer)

The pump module tops are not parts you can buy separately and there are no parts sold to repair.

Sounds like you found your problem.

bob

 

The more I think about it the more I see whats going on.

After looking at Jim's fix he handled the bottom seal, but I don't see how he dealt with the upper O ring on the canister where the pump generates the pressure. Unless I'm missing something.

I wonder if an injector O ring would work. Either way the tank has to come back out. On the plus side all the bolts are loose.

 

If you are NOT going to use the 'jet-pump' part of the plastic module, then just buy a pump for the X300/X308 and attach the hose directly to the pump motor fitting.

Drill a hole for the hose to come out of the pump module top directly from the pump.

Put a strainer on the bottom of the pump and poke it out the bottom.

Just use the plastic housing to hold the pump in place.

That is how the X300, X308 and 4.0 X100 pumps are mounted in the tanks. Just vertical with the strainer touching the bottom of the tank and a hose on the pump to connect to the metal tube in the tank to the outlet fitting. They do have a steel cylindrical wall to slow 'sloshing' during cornering to keep some fuel at the pump inlet.

The return hose can be fitted to the original connector on the top of the plastic module so the fuel can flow through the little screen and dump inside the plastic housing.

The pump already has a check valve but the disadvantage of nothing surrounding the pump pick-up that cornering with a really low fuel level might 'starve' the pump because of 'sloshing'.

bob

 

This was how the fuel pump in my Volvo 240 was. It had a low pressure pick up pump in the tank that fed a high pressure pump under the car. I replaced the pump in the tank with a high pressure unit. I’m pretty sure it had a built in cup to prevent starvation during cornering and low fuel levels.

I guess knowing what the problem is, is half the battle. I’m going to see if I can leave the car where it is a little longer and put something together. I imagine as long as the car has more than a 1/4 tank it should be fine.

 

Well for what it’s worth I did find the problem. The upper seal is supposed to be held in place with a small metal cap and in my case was actually broken. When I had it apart the first since it was wet I didn’t see that the plastic was broken. I just thought it popped on was held together by the top of the module. When I took it out yesterday and it sat overnight it was a little more obvious it was broken. And it’s all coming together.

I’ll get some pictures posted up when it’s all back together of what was wrong and how I fixed it so hopefully someone else gets it on the first go around.

And those stupid clips. Even with a good light, more room, a long screwdriver and a magnet I still lost one.

 

Well I had it up and running on Wed. Ran like a champ, leaked fuel like a sieve. I damaged the O Ring on the return line and it was leaking fuel everywhere.

Since I didn’t want to take a chance being on the phone for 20 minutes I looked up the part numbers for the Rings and called Jaguar in the AM. I had to buy a pack of 5 at $3.90 each but went ahead and ordered them overnight to have them on Friday before the weather turned. Called around 1 only to find out that he accidentally ordered the clips. I had asked about that as well but they were almost $6.50 each and again I would’ve had to pay for 5 so I passed but that’s what happened.

So now I’m looking at Monday and the temps will be 30 degrees F colder.

 

Since there are various threads about actually removing the tank the only things I could add would be to.

1. Remove the gas cap and let the tank vent. It may drip a little fuel but it won’t run out all over the place if there is no pressure.

2. Get the fuel line clips off first. If the tank is loose at all it makes it harder to get the clips off as the tank can move and push the clips back a in to the trunk.

3 Have a good light and a magnet on a stick handy. It still may not help but at least you tried.

4. Get New O rings.

And here we go.

Here is the pump canister out of the car. Compete and unmolested.



This is the canister top and you can see the broken ring of plastic. This is all supposed to be assembled and the reason for my low pressure. It’s just spewing inside.



I drilled a hole to run a hose from the top of the pump to a metal fitting I found that had a barbed wire and and the line in the tank will attach.



This shows the upper hose and the lower extension I attached to the fuel pump to run out of the bottom of the canister In to the tank. I used a length of 3/4 copper pipe. It wouldn’t fit over the end of the pump so I heated the pipe and then slid the pump on and immediately cooled it and it was tight.



I drilled a hole thru the bottom and ground down the end of the pipe for the sock.



This is the filter sock popped on the copper tube.



And here it is all together and ready to go back in.



What you can’t see is the old bottom seal still in place stabilizing the pump.

 

Hi Joe,

Congratulations and thanks for the update and photos. Let me know if you have any trouble getting them into your post - I may be able to help.

Owners of earlier cars with external fuel pumps should be aware that fuel may run out of the tank when the lines are disconnected regardless of whether or not the fuel cap is removed.

Cheers,

Don

 

Man,did I ever miss out on this one!I hafta start checking in more often!

I just read your PM Joe,and just finished a reply to Larry,BEFORE I read up on

the thread

That is exactly the same fix I would do if the upper "o" ring on our pump can were bad.
Simply make the pressure can into a holder for the pump and stop all the issues with 20+ year old plastic parts,submerged in fuel.

Try some of the small engine shops or rental yards,they usually stock a good selection of "O" rings.

Cheers to a good repair,Cin's car is still going strong,no issues.

Best of the season to all
Jim and Cindy.

 

Ok I got all the pictures fixed and in order so hopefully they are of use. All in all this wasnt that big of a deal ( I say that now) I would've saved myself a lot of aggravation had I known what I was looking for in the first place but live and learn.

Right now I waiting on the O rings for the return line and they should be ready on Monday. So back up the car goes and on with the rings and clip. Cross your fingers

 

When I saw you had low pressure after installing a new pump I figured the seals failed. I had one do that to me.

Glad you persevered and got it straightened out. I am considering installing a second pump in my X308 tank as a back-up and alternate them every few weeks/months to keep them from seizing due to time/inactivity.

Pulling the tank is kinda annoying.

bob

 

You mention that you are having trouble with the clips, are you removing them or just turning?

 

I lost a clip one time and could NOT find it so I fashioned one out of a spring steel key ring and installed it. Years later it still held the pipe in place.

bob

 

Man, those O rings are a pain with the car on stands. Doing them when the tank is out is highly recommended. Took it for a quick Drive and its good.