1996 Xj6 - won't start - what to check?

[mhannon1966]

Hi,
This is my first Xj6, owned it for 6 months, it hasn't missed a beat, starts on the first turn, until this morning. Engine cranks over but doesn't start. I tried jump leads, but the battery looks ok. Does anyone have any pointers of where to start looking? I have seen a few mentions of crank sensor. Is that a good place to start?
Thanks
Myles.

[alec2824]

It certainly is! However, ensure your battery is in good shape and fully, fully charged - the electronics demand lots of volts! Then whilst attempting to start, does the rev counter register anything? This, apparently is a pointer to the crank position sensor or not!

[PeterDavisX300]

It certainly is! However, ensure your battery is in good shape and fully, fully charged - the electronics demand lots of volts! Then whilst attempting to start, does the rev counter register anything? This, apparently is a pointer to the crank position sensor or not!

I concur. When 'cranking, the tacho needle should 'flicker' a little up to about 200rpm, this indicates that the crank-sensor 'Should' be ok. Next place would be camshaft sensor, although I've heard of cars that start roughly when cam' sensor is faulty. As has been stated, check the battery for full voltage, and that it's 'heavy' enough for the car. Get someone else to turn the ignition switch to 'ON', whilst you listen for an initial 'zip' from the electronic fuel-pump. Although the fuel-pumps mostly are ok. The fuel system potentiometer JLM 12074 can in extreme cases allow the car to crank without thinking of firing.

Let us know how you get on.

[mhannon1966]

Thank you both. Bizarrely, after leaving it for an afternoon, it started on the button as before, and has now done so for the past two days. I'm sure the fault will re-occur at some stage, but for now, I'm going to arrange a service and just hope it was a blip. From reading through the forums, I have to accept that something will fail at sometime. Thanks again. Myles.

[alec2824]

I had an issue with my X300 some time ago whereby the engine was missing badly. It would start, run really roughly and die as it tried to pull away. I replaced the crankshaft position sensor and all was well. On inspection of the removed sensor, I found that the insulation on the wire lead had worn away - thus giving erroneous signals. Worth checking to see that the wiring is clear.