First things first.

Your car died, sad thought.

You found the coil leaking oil, GOOD find, and definately a prime suspect. The coil may have shorted, as said, and that would reek havoc with that module.

The ignition switch (electrical section) dropping +ve in the ON, and/or the START position is common enough, BUT, the fact the fuel pump is buzzing whilst cranking is a good sign it is OK.

I am unsure on the 6 cylinder engine, but on the V12, if the Coolant Temp Sensor (CTS) loses contact with the ECU that engine is DEAD. The CTS is on the water rail, near the coil, and has a 2 pin plug, much like an injector plug. The wires can/do break inside that rubber boot, so check the integrity really well.

If it were mine, I would be replacing that coil and the module inside the amp. If that fails to fire it, then a step by step diagnosis will be needed, and simply throwing parts at it will achieve very little apart from draining the bank balance.

 

I presume the car is still in the 'no start/no spark' mode? If so, you're lucky, as it's easier to diagnose a hard failure than an intermittant one


Besides what's already been mentioned.....

Have you carefully inspected the coil and module wiring? It's common for heat-baked wires to give trouble.

Have you pulled the distributor cap for a quick inspection of the rotor and the inside of the cap?



If you have a volt-ohm meter you can use this test procedure, which is lifted right out of the Jag service manual:


The test assumes a fully charged battery

1) Measure voltage at coil "+" terminal with key "on". It should be within
one volt of battery voltage. If not suspect a problem with the wiring to the
ignition switch, or the switch itself.

2) Measure voltage at the coil "-" terminal. Result should be the same as at
the "+" terminal. If Ok, go to step 3. If not....
Disconnect the wire from the amplifier from the "-" post of the coil and
measure voltage again. Less than 2 volts means the coil is faulty. More than
2 volts means the amplifier is faulty.

3) Disconnect distributor pickup coil from the amplifier (this is the
harness from the distributor that plugs into the amp). Measure resistance
across the terminals. It should be 2.2k to 4.8k ohms. If Ok, go to step 4.
If not, replace the pickup.

4) Reconnect the pickup to the amplifier. Measure voltage at coil "-" post
while cranking engine. The voltage should drop. If OK, go to step 5. If
not, the amplifier is faulty.

5) Check distributor cap and wires, distributor rotor arm, spark plugs, coil
wire



Cheers
DD

 

not my intention to confuse things more, but here is a webpage that's been kept going since before I bought my XJ-6 in 1989, and it lists substitute parts for the XJ.

I understand pricing in AU is higher than US, so you might use the info to shop online in places like Rockauto.com which sells these substitute parts for low prices.

XJ Parts Interchange Guide

 

thanks jose, thats a a good page


Will do the procedures that doug suggests, and Grants advice is indispendisble .


Peter

 

Easy way to convict or exonerate the ignition switch and the wiring related to it.


Jump 12v from battery + to coil + and crank. if the engine fires, look into the switch and the related wires and connectors.