Ok, no fuel to the rail.
CLUES:
1. stalled driving slow speed- started sputtering, then died
2. replaced relay- YAY! ran great for about 3 short drives then dies again
3. Got it started AGAIN in the driveway, ran for a straight 10 minutes then when I shut (sorta slammed) the trunk- BOOM, same problem. (wiring issue?)

Removed and replaced pump- worked on the bench, odd.
Bought new ignition switch (old one was loose anyway) nothing.
Plug everything back together- nothing. Zilch.
Relay-Works fine
Fuse- have 12V for a second when switch turned to on
What to do next? How is it that I have 12V at the fuse, BUT only 5V at the plug connector for the fuel pump?
I cannot, for the life of me, find a 2002 XK8 fuel pump area wiring diagram. every other year, sure.

I think I identified the pump wire because it has 5v for a second then zero. the other non ground wires get 5v constant.

It *seems* that I have an issue between the fuse and the wire harness connector. Could the ECU be contributing? Seems interesting and wire/short related that it dies as soon as I shut the trunk last time. And I mean it was PERFECT until it shut, and then nothing. Won't pump with the trunk open or shut, so there is that.

 

The electrical guide is the same for 2001/2002MY.
When I worked at the dealer, we got annual electrical guide updates/replacement 3 ring binder pages.
In 2002 we simply got a replacement cover page that had printed XK8 Range 2001/2002 Model Year
Electrical Guide.
There was no change because the 2003 MY car was in preproduction and soon to be introduced.

The document you want is S2001_XK8.pdf

The file size is 4972kb.(Gus should have it on his site jagrepair.com)

 

Thanks MCM! As always.

I *think* I may have things in theory tracked down. When I got it working before, I was swapping out relays and fuses in the trunk fusebox area..... then when I shut the trunk it stopped running. I am almost 100% that it is a short or bad wire or bad something in the actual fuse box.

Raining today, so will have to wait for tomorrow or Monday to address.

 

I read this on the internet,(So I know it's true) that the wiring is so light on the XK8's that if the fuel filter stops up it will overload the wires on the fuel pump.
Wheather it's true or not check your fuel filter and make sure it's not the root of your problem.

Jack

 

I don’t have a lot of experience on “modern” cars, so this may not be a surprise to most. But I am shocked at the skimpy wiring on these cars. The wires are so delicate it seems like they are guaranteed to break.

Z

 

At the fuel pump: Black wire is ground, Brown/White is 12V from fuse 7 (20A)
Relay: Pin 1: +12V (ignition) from fuse 3 (5A). Pin 2: Ground from ECU. Pin 3: +12V from main fuse in front of battery, Pin 5: +12V output to fuel pump through fuse 7.
If you short pin 3 and 5 the fuel pump should run.

 

Ok, looks like the aftermarket wire harness had a swapped + and -.
Changed them and got some light stumble/idle
then no pressure. just a dribble out of the Schrader valve.

Replaced the fuel filter as well.

Now looking at maybe pressure regulator? I would think I would have pressure at on before start though.

 

so.... I connected a hose to the open schader valve and there is a minute level of pressure, but there are also BUBBLES. and they keep coming. Pull the tank again and replace the hose?

 

Victory.

I reopened the tank, replaced the filter and ran a small bit of air back through from the shrader valve and now it is running- I DID (when I replaced the pump last week) that the connector to the pump dongle was fried. I suppose the filter could have been clogged, which made the pump work overtime? It s now running as expected, even drove it to work today!