Hello all,

I have a 1997 XJR6 that is refusing to start, common issue it seems from this forum. When I turn the key I can hear a clink sound but the engine will not turn over. I supplied the starter motor with an independant 12v supply and the car started first time and drove fine, the returned as soon as the ignition went off.

From research on this forum I have tried the following

Parking microswitch. I believe this is working, I have tried giggling the shifter and I can hear the switch. There is a warning buzzer if I turn off the ignition when the car is not in park
Fuses. All checked with a multimetre and fine
Battery. Fully charged, I removed it from the car and charged overnight
Cable to starter motor. The cable that runs from the firewall behind the engine to the starter has been checked and appears fine

I dont believe there is an issue with the starter or crank sensor due to the car starting when the power supply was on the starter motor.

Any further advice would be much appriciated.

Thank you

Colin

 

In rotating the key you will get many things to click but the one of interest is the starter solenoid relay in the following pic

You have to put your finger on it and feel as there are others in the area that click

The relay can click closed and still be bad on the internal contacts

By it clicking it does prove you have agreements ( enables ) satisfied ( like the not in park switch ) to allow the starter solenoid relay to close by a commanding ground provided by the BPM

This relay can be swapped with the same part # like a headlight , fog light , AC , but not the ECU controlled relay

The relays in the sockets holder can be stuck by a waterproofing o - ring and can be freed by penetrating oil spray once flipped upside douwn ,. the sockets holder unclips straight down

Your supercharged engine uses a different transmission that does not have a rotary position switch on the more common normal aspirated inline 6

 

There are a couple of fuses in the starter circuit

# 12 / 10 amp right engine bay fuse box , solenoid relay control

# 3 / 25 amp left engine bay fuse box , solinoid relay pass through muscle power

# 5 / 10 amp trunk fuse box , BPM

One for the security loock contrul unit

Battery heavy 250 amp fuses by and fwd of the positive battery post

tighten the terminal nuts as can come loose

and

Chip in key , the print does not show a RF exciter / transponder, but the US models do not have one until 98 , your British model probably has one for 97

Never tighten the positive battery post clamp bolt too tight , breaks the special nut underneath

and never install the battery in backwards , positive post goes in positive direction of car travel

 

H Parker,

I double checked all of the fuses and swapped the ones you listed. I swapped reply 4 in the left hand fuse box (starter solenoid. Batter terminals are tight and everything electric works fine. Im not sure what you mean by chip in key?

Thank you for the help

Colin

 

Another thing then may be unrelated, on the journey before this issue started there was a loud popping noise when I set off from some lights. I assumed I had driven over a bottle but now Im woundering if something electrical had given up the ghost.

Im in Manchester, I found this guy online https://www.stephenheywoodjaguar.co.uk. Does anyone know if he is any good?

 

There is a inertia / crash switch that trips and shuts things down like the fuel pump

This switch can be fickle and not reset

You can put a paper clip in the connector at the 2 white wires

for your right hand steering British model, it is by the gas pedal as a rubber bulb

it is in front of your ECU , no panel removal needed

 

From what you described, something in the system seems to refuse to send an OK signal to the starter to crank. When this happens, it could be caused by a faulty body processing module (BPM). A less likely cause could be the immobiliser, but it is probably not the reason in your case as you still hear a click sound from the fuel pump relay.

 

I was unable to test the above unfortunately. The car has only driven one mile since I last charged the battery overnight. It was flat today, showing 11.4v and would barely open the central locking. I will shop for a new battery, it needed one in any case.

I believe from other pages that the lights would not work in the event of the BPM failing? They do, or at least did.

Thank you for the help, I will let you know if it was a duff battery all along.

Colin

 

There is a thing with this car called a parasitic battery drain where the car does not go to sleep after key removal , this is a mechanical key in key out linear switch on pin 4 of the ignition switch connector

This switch can be cleaned and lubed but is a dripping mess

This is separate then the immobilizer circuit

One thing you can do for parasitic drain is rotate the steering wheel position control switch out of the Auto position other then cleaning the ignition switch

A chip in the key would be a lump by the black plastic of the key and is needed to disable the immobilizer , this chip in not needed on USA models

A test of pin 1 is not the most confidence building as the pin 1 rotory switch is a momentary contact and will waver on your meter

The ignition switch relies on a good car frame ground on pin 5 on the car side of the ignition switch connector , I found corrosion in this connector

The rotory switches on pins 2 and 3 are in contact at the same time depending on the key rotation position

There is a map on page 38 of your wiring guide

jagxj1997.pdf (jagrepair.com)

Again, this map can be confusing as it is labeled as rotary position and not pin position in the 4 maps

 

What market was the car built for? Canadian and USA cars do not have an immobilizer, rest of the world does. If it's a ROW car, then we could be looking at the security module not sending the "OK to crank" signal.

 

Your ECU hardware is the same through all ranges and world areas with the exception of the V12

The software including Maps particularly the supercharger Maps is the difference and XJRengineer has present experience with changing the software including security inhibits blanking

So this means you possibly do not need to obtain a supercharged ECU , ask Andy for details as he has a master software

Keep in mind the ECU has a external dedicated case ground strap

Andy bracket for ignition timing biasing and different size of the supercharger pulley that many people have done both

Your engine regulation is here ...............

The ECU details are here for a GEMS V8 version ( same manufacture ).........................

Your engine mechanical manual is.................................

There is a Jaguar whole car service manual that is too big to download through this site so I broke it into 5 peice ; this whole car includes the manual transmission information