It's 93 Xj6(xj40) RHD with 150K(KM) on it,

Lately (within a period of month), it has had twice would not start (dead silent), except Dashboard light up, clicking (relays) sounds under the hood.
stereo, power window, lights all work fantastic. Battery checked by mechanic in good condition.

Check around the fuse boxes, no loss fuse,

check the Forum here, but try desperately couldn't find the so called "Inertia Fuel Switch" to reset, both driver and passenger sides, clawed underneath with torch light, just couldn't see any "tripper switch" alike.

Also try to push and pull the gear shift , make sure it was in PARK. (It always was)

Solution: None constructive were done by me,
but after helplessly for 30-40 minutes. It cranked up on next key turn again.

Don't know what exactly wrong. It starts sometimes and it won't sometimes.

Any advice please, thanks a lot.

 

Hi I am surprised that this has received no replies so far.

It does not sound like the Inertia switch, but you can check it by removing the cover down near your right foot. You will see the switch button.

Others will chime in.

 

Thanks a Lot,
let me check this out in next couple of days.

Cheers

 

Clean the crank shaft position sensor after I did all the intermittant non starts went away!

 

Charlie:
To the best of my limited knowledge, if your inertia switch were tripped, the car would never start until reset. Also, a faulty CPS (crankshaft position sensor) - which in2 rightly identifies as the culprit in many non-start scenarios - typically allows the engine to crank but not fire. If your engine isn't even cranking, the problem sounds electrical in nature to me. I'm wondering about the "clicking relays under the hood" you identify. Is this noise continuous or does it just happen once? Could the noise becoming from elsewhere? Could this perhaps be as simple as a failing starter?
Cheers, Scott

 

Thanks a lot guys, appreciate for your sharing of knowledge.

My Jag fail to start again 10 minutes ago, same thing as I described,
dashboard lights are up, stereo fine, electric window works.
but nothing happening under the hood, except one quick Clicking sound and one-long-ZZZZ (for about 1-2 seconds). Starter wasn't even spinning.

So, if starter not even spinning, I probably should assume that CPS is not the problem here. Perhaps, it is the starter.

Normally, if I wait for 15-30 minutes, it will crank up. Let me just see that.

 

One Hour passed, I have tried 3 more times and the starter nor the engine cranked up except dashboard lights up.

Here I attached a photo of "Initial Fuel Switch" (which I hope it is) on the right foot position (driver side, behind fuse box), I pressed down the switch, nothing really happening after that even.

Any advice? Please
THANKS !!!!

 

My problem solving continue into 2nd hour after reading some forums on possible causes
(1) Security System, although my XJ40 has none, but I did try, locked it and unlocked it again, then nothing happened as the problem persist. While sitting inside, locked central lock and unlocked central lock, still engine won't start, starter won't crank.
(2) Battery enough voltage and not enough amp to crank the starter, OK, I cable connected the XJ with another car's batter(while running), still engine won't start, starter won't crank. I let the car ran for another 5 minutes charging the XJ's. still engine won't start and starter won't crank.

I am now nearly sure myself that the Starter Motor is dead......
Any other advices will be appreciated.

Thanks

 

check your starter relay jump across blades as the ground may be bad

 

Check the volts on the battery when you try to crank it (not whilst being jumped!) ....do the volt drop off?...that would show a hefty load like a jammed motor, that might also lead to a buzzing, (the windings rattle on the motor like transformers ie on bat chargers
or a poor battery ).

Not withstanding the above.
you say there's a click and a ZZZZZZZZZ. noise ??
This could be the solenoid clicking in and the starter motor is running but the little drive is not being thrown forward ....not sure on these whether they rely on inertia (if so look for bad Earth or low bat volts)if not the motor is failing.
If it has a solenoid to throw the cog forward I would whip the starter off and test it on the bench.
Again not really sure if the bits and bobs on the starter are repairable (used to be in my day but then a good man with a red flag was hard to find)

or... is the ZZZZZ more like a very rapid (loud) hammering? that could be a solenoid throwing in and out .
Another thought ...is it a REALY gently click and zzzzzzzzz? that could be the relay

 

also a little mor detective work
is the clicking and buzzing ONLY when trying to crank or when you turn the ignition on.....?

 

I had the same problem with mine. Tried all sorts to sort it. Eventually, thanks to one of the tech guys on here (sorry, but username escapes me at the minute).

Check the 'P' is lit red on the 'J gate'. Mine wasn't lit but when I jiggled the gear lever around, it lit up and she started straight away. Turns out it was a faulty park/neutral sensor.

I know in a previous post you said you had moved the gear lever, but you never mentioned if the 'P' was lit up.
Something to try i suppose and, with my limited knowledge, it's the only suggestion I can offer.
Good luck!!

 

Thanks a lot in2 again.

I tried to locate the starter relay according to the diagram on
http://www.jaguarpartswholesaler.com/1701311.html
but it doesn't seems to coordinate with my Jaguar's (feeling kindly of stupid here). So, I swap the Bosch relays (with the same serial number) and tried to see whether it work.....still not running...

 

Thanks a lot,

 

Thanks a lot, I did check and confirmed it was in P with the red lit on "P".
also tried to start on "N", unfortunately, both didn't help....

 

Really appreciate your contribution, thanks.

the ZZZZ is a gentle and short, undetectable when sitting in the driver seat, unless standing next to the hood open. I also suspect it was the sound from the fuel pump? but on the continuous try with ignition key, the zzzz will not come up only one clicking per turn key. then it is dead silent, not even a little humming from the starter.

This afternoon, I just got back from my mechanic who was working on my 1974 BMW 2002 (replacing a bad carburetor and engine flashing / carbon cleaning), after hearing my Jag's issue, he also suspect the starter might be out. By the way, I check the ground and wire, seems to be fine.

Well, the mechanic will come by the house tomorrow to take a look of the Jag, let's see his diagnose. and will keep you guys updated on the progress.

All very much appreciated. Best Regards.

 

Before my BMW mechanic arrived this afternoon, I turn the Jag's ignition key again, WOW, it immediately started up without hesitation. I have done nothing this time. Quickly, I drove it 5 miles to my regular Jag mechanics, he is very sure that was the gear in "P" park position, the contact could be faulty even the "P" lit up in red. He seems to so sure about this common manufacture defect.
However, I did tried several times in the past few days on the gear shiftl, "P" lit red never help to solve the failure starting problem. The mechanic tried several times to start and stop, the Jag worked brilliantly in his garage. (But he found the brake pump maybe weak, needs replacement".
On my way home, the Jag stalled twice in the heavy traffic due to low RPM! I had to drive with left foot on brake and right foot on gas. Until I reach home, reversed back to my garage, then I tried to started it again........won't start !!! back to square one....same old issue, regardless how aggressively I was shifting the gear to "P", it just won't start ....
a truly roller coaster ride emotionally!

 

It is like a boy-cried-wolf, now the Jag (after couple of hours) parked won't start, it started again on my turn-key without hesitation.

Now I have a analogy for all these, I need you guys to confirm whether it is logical. "A poor brake pump leads to inability to start a car". It is very much like the gear wasn't in "P" and car wouldn't start.
Remember back in the 80's, several incidents involving Audi's sudden acceleration, so manufacturers installed the sensors on the brake and gear shift. ie. you cannot start the car if the shift wasn't in "P", you also couldn't start a car if your foot is not pressing down the brake paddle, and because my brake pump running poorly giving insufficient pressure, so the sensor detects as my foot wasn't on the brake, so it prohibit the car to start. Sometime, the pump pressure is running enough to trigger the sensor, it starts just fine. Is this logical? any advice please.

 

I'm pretty sure you only need the brake pedal pressed if you are trying to start the car with 'drive' selected instead of park.
Could be worth a try starting in drive with brake pedal down. Could rule out park neutral sensor???

 

Thanks again,

The car fired up without hesitation on my first try today. But I did nothing, just simply turn the key. I tried to run it for 3 min., off and start again without problem. Then I put gear into N, foot on Brake, it fired up.
Repeat it several times without fail. Park Neutral sensor should be alright. Left the car run for 10 min to charge up the battery.
1/2 hour later I go back, it is non-starting again.
Tried several gear position, jiggle it around, made complete J turn and back (like my mechanic suggested), still fruitless........it is a non-starter.

I am going to check out the Starter Relay tonight, see whether I can by-pass it.
cheers.