On my 2000 xk8 that I recently put a replacement engine in. It started about 2 weeks ago. My wife started the car and fogot something so she turned the engine off. When she came out she restarted the car and it only went a couple of feet before it died.
When I got home the car started for me with no problems. Let it warm up then turned the car off. Tried to immediately restart the car and it wouldn't start.
Last Saturday checked the schrader valve and no fuel. Well at least now I know it is a fuel issue. First thing I checked was the fuses. All good. I swaped the relay with a known good one. Then I checked the fuel pump. A while ago I cut the connector that conects to the fuel pump conector off a parts car so I can take the the hot and neutral wires that go to the fuel pump and supply it with 12 volts. That is what I did and I could hear the fuel pump. Then checked the schrader and I had pressurized fuel at the valve.
Pluged the cars connectors back together and the car started. I thought it might of been the relay. Shut the car off and it wouldn't start again.
Started scratching my head. That didn't help either.
Checked the battery and it was under 12 volts. Disconnected the battery from the car and recharged the battery. Took it off the charger and it was at 13.1 volts. Then it was slowly loosing it charge. When it got to 12.4 I knew the battery was shot. The battery was still disconnected from the car while it was loosing voltage.
Replaced with a new battery. The car started right up and I drove it around for a half hour with no issues. FIXED.!!!
Until the next morning. My daughter was going to use it to go to work because her BMW has a coolant leak, guess what I'm doing tomorrow.
So tonight I tried to track down where the problem is. I disconnected the earlier connector and check the hot and ground leads to see if I had power there when the key is turned on. I got 12.6 volts, that is what the new battery was down to from trying to restart.
I got power at the connector, the fuses and relay are good. The pump worked with direct power. Logically, I watch a lot of Star Trek, it must be the connector. I had my wife try to start the car. No start. I jiggled the connector while she was trying to start the car. I heard the pump come on and the car started. While the car was running I jiggled the connector and the car shut down. My problem is definitely in the connector.
Tomorrow I will replace the connector with one from one of my donor cars. Then on to the BMW. After working on the BMW I won't complain about Jaguar design or engineering again.

 

Good find.

I had a similar intermittent fuel pump problem a while ago and it also turned out to be a connect in the harness on top of the tank. Infuriating problem, there was no pattern at all to when it would happen.

 

Well done on a difficult issue to pinpoint....

 

Thanks Jon & Charlie.

This morning I set out to do the repair. I thought I would take a close look at the connector to see if I can spot the problem before I start cutting wires.


This is the connector I'm having the problems with. It is on the top right hand side of the fuel tank.

This is the same connector from a donor car that I use to test the fuel pump. The brown & yellow wire is the 12v feed and the black wire is the ground.
When I looked at the connector on the car I noticed the the pin in the connector for the feed wire was pushed back into the connector about an 1/8 to a 1/4 of an inch. Using a small flat head screwdriver I pushed the connector from the back to its proper position.
Put it all back together. Turned the key to the on position and I could hear the fuel pump. Car then started right up. I jiggled the connector with the car running and it didn't die like it did last night. Drove it around a bit and restared the car several times with no issues. I'll drive it around this weekend to make sure all is good. Now on to the BMW.

 

I wonder how that pin inside the connector got pushed in too far. Perhaps road vibration over a period of time could do that if the pin was not properly seated to begin with. Little intermittent issues like this can drive me nuts when it takes days or weeks or longer to find the root of the problem....

 

On many of the connectors, the pins have a spring tang-like lock that snaps into a slot inside the connector. To remove the pin, one uses a cylindrical tool ( special tool) to depress the tang allowing the pin to be removed. Perhaps this pin was not totally locked into the connector when harness was fabbed and just loosen over time due to vibration. If no sign of heat, you are OK. My 2 cents on that connector.

 

I'm thinking this might be self inflicted. It's possible that my testing for voltage with my multimeter I could have pushed the connector further in the connector. Kstevusa is correct on how the pins lock into the connector and I might of hit it just right and released the pin. I tested this connector a few years ago when the fuel pump went bad. It is possible that I released the pin then and may have work it self loose. It's all guessing on what caused it but now it is hopefully fixed.

I wanted to post this thread to let other members and guests know this is another possibility to check out before you start removing the fuel tank to replace the pump.

Thanks for you coments and replys.