Looking for some help in resolving a problem. The car in question is a year 2000 supercharged XKR which was running fine when last used three or four years ago and has been sat in a garage ever since with no attempts to start it in the interim period. Have recently been trying to get the car running and back on the road. The car cranks over healthily but showed no hint of firing - spraying easy start into the air intake results in the engine running so this pointed to a fuel issue. I tried pressing the schreider valve on the fuel rail and found no hint of fuel pressure so then suspected the pump in the tank. I removed the collar from the plate on top of the tank to gain access to the pump and at this point realised there are two pumps in the tank (standard on supercharged cars). At this point I stopped trying to remove the pump(s) as thought it was time to ask for some advice! I've put a multimeter on the plug to the pumps and found one pump powers on briefly on turning on the ignition (roughly one second), whilst the second pump receives no power. Is this normal behaviour? I noticed inside the tank the outlet pipes of the two pumps are joined together with a Y-piece so I wonder if the second pump only kicks in when high fuel flow is needed. If this is the case and the one pump which should be running has failed, can I swap the wires over on the pumps (temporarily) to see if the car then runs?

 

pump 2 only primes

pump 1 then comes on with starter

pump 2 is variably switched under load

 

Thanks, that's very useful info.

So I assume from what you say, once the starter is engaged pump 1 then runs permanently until the ignition is turned off?

 

Yes, you can swap the wires, i did this by changing the contacts in the connector placed on the backside of the tank.

 

Fuel pump failure is one of the documented drawbacks to letting these cars sit for a length of time

Even when the 4.0 XKR’s are driven with regularity, if the car is not exercised hard enough the #2 will never be activated. So it’s not unusual for the #2 to fail unnoticed.from disuse.

Z

 

To test both fuel pumps quickly you can jump each pump to see if it works or not.

All you need is to make a jump wire with a spade connector on one end.

Remove the fuel pump relay and push the spade connector in slot 87 then touch the other end to the battery positive + terminal
if the pump is ok you will hear it running.

You need to have the battery connected to the car but dont need the ignition on to do this test.

You have the XKR so will have two relays to jump, one at a time to check both pumps are working or not.

The primary fuel pump relay is with the other relays in the fuse/relay board, and the secondary fuel pump relay is by its self next to the fuse/relay board.

This is a test so only hold the jump wire to the battery + for 5 seconds or so to establish if the pump works or not.

Some photos that may help.....









Sorry for the poor photo quality, Hope this helps.

 

Thanks for all the replies so far. I used the jump lead into the relay socket method outlined above and have established that both fuel pumps have failed, so the next job is to drain the fuel tank and try to withdraw the pumps through the top of the tank without taking it out - it’s a coupe with the central speaker hole in the shelf so hoping I can go in through that.

 

The fuse for fuel pumps is number 7 @ 20A in the boot/trunk relay/fuse box... cant remember if the one fuse dos both pumps.

Lots of info for changing pumps (and link leads if needed) on this site..

 

the 2nd or “supercharger” fuel pump fuse # is #22 on my 2002 XKR. Also a 20A rating.


Don’t know if that fuse number / location applies across all of the 4.0 XKR years


Z

 

Hi There,

I had the same problem and it transpired that the fuel pumps, use the petrol to cool the fuel pump motors. I had been using my XKR, for several years not realising, it was running on one pump only, until one fateful day when that pump failed. I investigated the issue and found both pumps had failed. I replaced the pair and wow, I forgot how fast the car accelerated and also how fast the fuel disappeared.....

I eventually stripped the pumps down and cut the end of the pump off, on a lathe and was amazed to see what had happened. The armature that spins in the center of the motor, had melted between the magnets and seized the armature.

It had been made apparent that many XKR owners, should not let the fuel gauge drop below 50%, as the petrol acts as a cooling action for the motors. I did post the pictures on here some time ago. Will see if they are still here...

I hope you get it resolved, as replacing them is pain in the proverbial if its a coupe....

 

XKR - Fuel pump failure dissection-20150818_082000.jpg
This is what it looked like.....

 

I am possibly having some fuel pump issues as well, but am a bit confused by the talk of two fuel pumps on the XKR. Do all XKRs have two fuel pumps or only the early models? I have a 2004 XKR. Hope I didn't hijack the thread.

 

I don’t have complete understanding of these cars, forgive if I make an error or two.

All the 4.0 L XKR cars had the 2 pump system. The 4.2 L XKR cars have a single (but pricey $$$) pump


Z

 

Thanks for the heads up zray, just as I thought.