Hello everyone. I need some help regarding my '95 XJ6. I have a problem with the car starting when the engine is hot. By "not starting" I mean that the engine won't even crank, if I turn the key and jump the solenoid it will fire right off. I know that it isnt the starter because I'm not even getting power to the starter. Ive tried the gear shift trick with no luck. Also, on a different topic, does anyone know where I can get a harmonic balancer?

 

Welcome to the forum. I don't know what to suggest for your starting problem, but if you do a Google search for Damper Doctor that will give you one source for repair. Also try the forum search for harmonic balancer and find many threads on the subject.

When you have time please visit the new member area and introduce yourself:

New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum

 

Hi Mark,

I'm not an X300 expert, but since none has replied yet, I just took a look at the X300 electrical schematics and the primary components in the starting circuit appear to be:

1. The ignition switch in the steering column
2. The rotary Park/Neutral switch at the gear selector/J-gate
3. The starter relay in the LH engine bay
4. The Body Processor Module (BPM) behind the passenger-side knee bolster or dash underscuttle (the schematic indicates that the "Engine Cranking Control" is a function of the BPM)
5. The Engine Control Module (ECM) behind the footwell trim at the RH A-pillar or post (the schematic contains this: NOTE: All vehicles require the 'Check Engine Signal Input to the Body Processor Module before the Body Processor Module enables Engine Cranking.'
6. The starter motor itself (battery power should always be present on the Brown wire; the white wire is the solenoid control voltage from the starter relay.

The fact that your issues seem to only occur when the engine is hot would prompt me to first check the starter relay since it is in the engine bay and most susceptible to temperature. You might pull it from its socket and check for corrosion in the socket and on the relay terminals and perhaps swap in a similar relay from a non-essential circuit. If the relay socket needs to be cleaned, it may be prudent to disconnect the negative battery terminal before touching the socket terminals with a small wire brush - I didn't check but there may be 12V always present on the Brown wire with the White tracer line connected to terminal 3 of the socket.

I've also heard about problems with the Body Processor Module - you might search the archives to see what you can learn.

I hope an X300 expert will chime in with some more specific help.

RJ's tip about the Damper Doctor is a good one - I got a rebuilt harmonic damper for our '93 at a fair price and it's still going strong several years later.

Let us know how it goes.

Cheers,

Don

 

Yes as Don says check the starter relay first. You should always have 12v on pin 3 and you should have 12v on pin 2 when the ignition is in position II. If you don't then check out the ignition switch.

Next check Pin 1 of the relay. It should switch between 12v and ground when the engine is cranked. If it does, then the problem is the relay.

If not then the BPM should be checked next. The BPM controls cranking and requires a number of conditions before it rescinds the starter inhibit signal.

1. Check Engine light must be on.
2. Transmission must be in Park or Neutral (as determined by the decoder module)
3. The security system must be in a disarmed state.
4. Ignition switch must be in position III

The easiest way to check the BPM is to monitor pin 33 of the yellow connector on the BPM. The signal should change between 12v and ground when cranking. If it doesn't then either one of the four conditions above are not correct or the BPM is faulty.

If you do get the correct output, then the problem must lie in the Park-Neutral microswitch or the wiring/connectors.

Here is the circuit diagram.

starter circuit.pdf

 

Thank you very much! your advice has been extremely helpful!