Hi, everyone, I have a problem which I posted about before, but now I have new information I think I need to start again! My 2002 XKR has been intermittently failing to start and because both fuel pumps have only been in for about 3 years and 20k miles I didn't think they were the likely problem, although they are aftermarket pumps.
I have learned some tips, largely from this forum, and now have a way to get the car running when it fails to start! It appears that my secondary pump has been OK all along, because every time it has started and run for a few seconds, no matter how many times I've tried, it never exhausts the fuel, and when I apply 12v to the relay directly the pump runs OK.
The primary pump does not run, even when a wire is run directly to the relay from the battery, which indicates the pump has failed? I have had an auto electrician check the function of the relay and it is fine.
If the primary pump relay is removed, I can get the car to start on the secondary pump after 6 or so attempts, but if I leave the relay connected to pump 1 it will revert back to the 4 seconds or so of pump 2 running, then cutting out.
If I run it without the pump 1 relay, I of course get a restricted performance message and a P1230 code (low speed fuel pump condition) - If I cancel this off it will drive ok for a while then revert.
So, because after many attempts to get anything out of the primary pump it appears to be dead, I have booked it in to have 2 new pumps fitted, and this is where sod's law comes in!
Yesterday, I prepared the car for having the tank removed by removing what I can so that the tank is loose and ready to be detached from the fuel lines, and out of interest checked which wires went to which pump, I checked for continuity from the relay terminal to primary pump positive at the tank upper connector and everything seemed ok, then when I reconnected the multiplug I put the wire from the battery terminal to the relay and... the pump ran perfectly, time after time, car starts and runs with the relay in place exactly how it should, and now I wonder if I replace the pumps tomorrow, whether I am going to have a period of thinking everything is ok, then get stranded again! Any ideas would be welcome!

 

It does sound like you had a dirty or loose connection at the multiplug - I would spray it with contact cleaner before putting it back together and try it. I certainly wouldn't bother changing the pump(s) at this point for what sounds like a wiring problem.

If you search the forum you will find a description of how you can swap the wiring for pump 1 and 2 - someone even put a couple of switches in so they can swap between pumps on a regular basis. Might be worth looking at in the future if you find pump 1 is dead again. Another thing you might want to do while the tank is out, is cut a hole in the parcel shelf so you can get to the top of the tank without taking it out - it will make fault finding a lot easier in the future. One final thought, when you are testing the wiring, use a 12v bulb rather than your multimeter - that will tell you if you have a good connection. A multimeter doesn't tell you if the wiring will support a load or not, only that it is has a very low current connection.

 

Good thinking about the bulb, I'll get onto that now! With the tank "loose" apart from the fuel lines underneath, there is a fair bit of movement towards the rear of the car, it almost seems that if I open the tank I might get my hand in and feel for the 7mm bolts which hold the pumps in - is this really not possible? Has anyone done this? (my car is a convertible)

 

If you are going to test it again with a bulb, try roughly wiggling, twisting, and pulling on the wiring to try and see if there is a loose connection, or broken wire somewhere. It's possible moving the tank etc pushed a loose wire back into contact temporarily.

I'd still cut a hole in the parcel shelf while you are in there. Coupes have the subwoofer there already, convertibles need that hole adding in (some people don't like fixing Jaguar's design mistakes like this, but I feel it's a real world improvement).

 

just stock up on a bunch of quick connect release tools and shove with a screwdriver

once that’s out removing the tank is the easiest thing ever

 

Right, a development! I just pulled the tank towards me for easy access and disconnected the multiplug on top of the tank, sprayed electrical cleaner into the terminals and put it back together, the car started then stalled. I checked via a lead from the battery direct to terminal on the relay and the pump was dead again - until I shoved the tank forwards and as it hit the bulkhead the pump sprang into life! Is it some loose connection inside the tank? Continuityto the tank seems pretty solid?

 

Found it! The multi-plug to the right of the tank as viewed from the rear caused the pump to stop and start when agitated, so I sprayed all the terminals with contact cleaner and tried to clean them as best I could with a pointed Dremel attachment, and now the pumps both run!
I'll just give it another clean tomorrow to be sure, then put my boot back together again! Thanks for your help guys!