Jaguar Repair: 84 XJ6 Series III No Power to Fuel Pump, air flow meter, inertia switch


Question
QUESTION: I recently piked up an 84 XJ-6 Series III. The previous owner could not get it to start after sitting. He replaced the fuel pump, Injectors and filter. I also have not been able to get it to start, There is no power getting to the fuel pump. If I jump the fuel pump it will try to catch but never quite does. I am charging the battery as I write this. Could this simply be a relay issue? If so, Wich one do I start with? Any and all help will be greatly appreciated. I am hoping to restore this sleeping beauty back to original condition.

ANSWER: Hi Brent,
The test of the fuel pump system is to remove the air filter, turn the ignition key to the on position and with a finger reach in the front of the air flow meter and open the flap. If the system is working the pump will run and you can hear it run while under the hood.
If it does not run confirm that there is power (Key on) at the white wires going to the pump relay. The pump relay is the middle one of the small relays. (black) The other black relay is the main relay and the small red relay is the diode pack. The larger relay is the starter relay. These are mounted high on the firewall behind the intake manifold. If you have no power on the white wires with the key on, check the inertia switch on the passenger's door hinge post.
Be aware that the Ser.III required a "Deepcharge" battery like a diesel or marine battery to start. Simple test is to check to see if you have a good ignition spark when trying to start.
If this does not lead you to a fix, let me know and I will walk you through the "No Start" correction.
Howard

---------- FOLLOW-UP ----------

QUESTION: Howard,
Thanks for responding so quickly.
I ran through what you said to do, Checked the white on the relay...I have power there. Checked the inertia switch.....The red post is in the down position. Bought a new battery with 850 cranking amps. Still no power to the fuel pump. I can only get the fuel pump to pump by jumping directly from the battery.  Time for the "No Start"?

Answer
Not yet, you still need to see why no power to fuel pump. Remove the pump relay from it's socket and look on the relay to ID pins # 87 and # 30. Then take a short wire with a flat spade (male) connector on both ends and plug one end into the socket where # 87 was and turn the key on and touch the other end of the short wire to the socket where # 30 was.
If the pump runs, Look at the relay again and ID # 85 and # 86 and which socket they went into. Then take a test light and attach the clip on a good ground and probe # 86 to see if it is powered with the key on. Then attach the clip of the test light to a 12v power on the car and with the key on see if #85 is a ground. If all of this is so, get a new relay. and repeat the airflow meter flap test I listed earlier.
Let me know
Howard