Hi my 98 xj8 is not starting, it cranks battery seems fine but just not firing, at times it is so close I thought that it had started, sat for a few days previously due to snow , I tried pressing the accelerator pedal and cranking but no success, I heard that this might work but not yet at least, any advice suggestions appreciated Many thanks in advance Trevor

 

From what you have done so far I would have to guess either fuel pump or bore wash.
See if there is a good spurt of fuel when you depress the schrader valve on the fuel rail after turning the ignition on.
If you have fuel pressure remove the spark plugs from the right bank and add a little oil into each cylinder, about a half ounce. Or check the compression if you have a gauge.

 

Thanks, how do I check the Schrader valve, I'm an amateur so take it slow!!! Trevor

 

It looks just like a tire valve, but on the fuel rail.

 

Pushing down the accelerator pedal at start will "stop" fueling and will not "aid" in getting it to start. Did you by chance go out the last time it ran and only start and run it for a few seconds?

 

Just to chime in here, I have a 2000 xj8 with about 130k and had been running fine with the exception of decreasing fuel mileage and occasional hesitation. I attributed this condition to a MAF sensor which I intended to replace.
Then it just stalled, and did not want to restart. Luckily it was at an idle in my driveway. No tow job, and no unseemly noises like a tensioner failing or timing chain jumping.
I pulled cam covers to examine the secondary tensioners and found them failing, i.e. plastic shoes breaking up. Although I still didn't suspect that this was the cause of stalling or refusing to start, I knew it was a job waiting to be done.
Now after completing the chains and both primary and secondary tensioner replacement, new coils, new plugs,and new MAF sensor and checking fuel pressure both key on burst and constant flow,I'm still unable to get her to run. I have received plenty of encouragement as well as sound advice from my Jaguar family for which I am gratefull. In my case the spark plugs appear wet, which infers to me that it may very well be an ignition problem. I had new iridium plugs with a .042 gap. I just picked up a set of NGK Platinum I plan on trying. Like you mentioned there were moments when it seemed so close or even started briefly but my quest continues. BTW when it stalled initially my code reader showed MAF fault and VAF fault.