I purchased a 99 XJR a little while ago...it was not running and I was told it needed fuel pumps.. After dreadfully changing the 2 tank pumps (1 was bad, the other ok, but I put 2 new in). The problem I'm having is the pumps are not priming or running when I try to start the car. There is power to #30 on the fuel pump relay,( the 2 fuel pump relays are brand new) but there in no power getting to fuse 7. Does this make sense? If I take a jumper wire from the positive terminal of the battery and put it into where fuse 7 goes, the pump runs and I can start the car. Ive been trying to figure out what Is going on for weeks, to no avail.. Any input would be appreciated.

 

Editing

 

Thank you for the diagram. So if I'm deciphering it correctly, the power goes from the relay to the fuse and then to the fuel pump? so if I don't have power to the fuse, something is preventing the relay from switching and conducting power?

 

Second FP is not commanded on until the ECU sees high RPM

You can remove battery positive cable

Remove All ECU connectors

Reinstall positive battery cable

Key to run position

Take socket in hand not ECU 1 and 9 one at a time to ground to verify integrity of circuit by hearing both pumps run

Remove battery positive cable then reconnect ECU connectors

Reinstall battery positive cable

 

So if I’m understanding. With battery disconnected, disconnect plugs from ecu, then reconnect battery. Then ground pin #1 and 9 on the socket side, and the pumps should run?

 

Yes the connector in hand not the ECU . The ECU provides a ground to pull the control coil on the relay to close the contact providing power to each pump . The control circuit is low current so no arcing hazard .

 

Thank you so much for the input. I will be back at it tomorrow and I’ll let you know how I make out.

 

Check the #16 ( 10 amp) control fuse at the left heelboard rear seat as a least intrusive try before removing ECU connectors

See my updated coloring pages above . Mom is so proud

 

Great diagrams! So here’s what is going on. I have power to fuse 16 in the rear left passenger area. Pulled the ecu plugs and grounded the pins on the plug side and nothing, pumps did not run. Is there something else I can check to see why relay is not making a connection? I pushed inertia switch, don’t think that’s it. if I jump relay pin 30 to 87, pump runs. Any more ideas would be great. This is driving me nuts, but I just learned so much from you, I appreciate it!!!

 

So lets split the circuit in half , the power side and the control side

Draw a line through the middle of the # 1 fuel pump relay connector from left to right on the print . Top half being power . Bottom control .

Look for 12 volts at the socket # 1 which will be one of the 2 smaller sockets across from each other .

The other one across will be # 2 socket which is ground seeking provided by the ECU .

Disconnect the battery and take the ECU connector EM13 position # 1 to ground .

Read that you have a ground back on the #1 fuel pump relay connector at that #2 socket

Don't worry about the #2 fuel pump circuit at this time .

Next look at the power half of the # 1 relay connector .

Look for 12 volts at one of the connector's two larger sockets . This will be the # 3 socket in the print .

You have proven you have a good ground as the power goes through the pump to the ground stud when you hotwire it so we are only concerned with the 3 socket's test points

I don't have a reference to the # 30 and # 87 mentioned as they are probably used on a different print

 

Thank you, probably won’t have time until Tuesday night to try that test. The 87 and 30 are embossed on the female end where the relays plug into. I’ll check to see what #’s they correspond to on the relay... thanks again for the help!

 

Seen that with alot of those 2 numbers with different car models . My model is a X300 so I don't have an example in front of me . Mine is easy to look under the connector to see the wire colors , yours may not . Wire color codes on page 16 below :

http://www.jagrepair.com/images/Auto.../jagxj1998.pdf

 

where did you get the diagrams from?

 

Gus has all the electrical guides on his site (jagrepair.com) because I sent them to him YEARS ago.

He has so much info.(all you need)

 

Thanks man! do you know of any the dealership computer programs that still work?

 

I have no idea where in the world you are.

The Jaguar dealer I used to work at is closed down for all repairs. Land Rover is still going strong. (Jaguar Land Rover parts dept sells parts for the Jags)
Many of us have dealer diagnostic devises (WDS/IDS) so I don't rely on anyone for that service.