Not another fuel pump thread!
#1
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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.
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.
#2
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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)
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)
#3
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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 *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.
#4
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#5
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#6
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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.
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.
#7
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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.
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.
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#8
#9
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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!
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!
Last edited by dsnyder586; 04-02-2024 at 11:24 AM.
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