Jaguar Repair: 1985 XJ6 Vanden Plas, starter solenoid, airflow meter

Question
I obtained this car over the summer. The ignition was broken but would start with a screw driver, no problem. The car has sat for a while and I just put a new steering column in with a new ignition. I put a battery in it and it would only show lights and gauges when I turned the key on. When I would turn the key all the way to start the car, all it would do is click once like the solenoid wasn't kicking in. It sounds like the fuel pump is constantly running with the key on. The battery sounded like it was boiling when I put it on my booster starter so I unhooked it. I really need to get this car running. I am mechanically inclined but electrical problems are not my strongest point.

Answer
Hi Lawrence,

You have several problems with the electrics. First the fuel pump is activated by the fuel pump relay on the fire wall and that it activated by the airflow meter only. Second is that the starter solenoid it activated by the metal can relay on the fire wall which is triggered by the ignition switch but only if the transmission switch is in park. These two problems are not connected.

You need to lay the diagram out in front of you and start tracing with a 12v test light. I like to start at the load and work my toward the power supply. Only pick one of the failed circuits to work on at a time.

Take the starter circuit first.

Remove the 12ga. white w/red tracer wire from the metal can relay on the firewall and take a jumper wire from the (+) post of the battery and make sure the car is in Park. Then touch the jumper hot wire to the end of the white w/red tracer wire.

The starter solenoid should activate and the starter should start running and spin the engine.
This tests the circuit down to the starter.

Next remove the relay from the firewall and look at the terminal lettering. The white w/red tracer wire should have been plugged into pin "C-4"
Next look at "C-2" and see if it is powered all the time (12ga Brown wire)
Pin "W-2" should have a double white w/Yellow tracer wires on it.
Have someone turn the key to the start position and that double white w/Yellow wires should get power.
Then test the black wire on pin "W-1" to see if it is a good ground when in "Park".

In those tests you have to find what is wrong with the starting circuit.

let me know and I will give you the tests for the fuel pump circuit.

Howard