Sir, Will P here, I have a 2000 xj8 vp with the 4 liter engine. I don't know on what site I learned the following, and if it is not on this site maybe this could go in to some kind of info heap.

One day I cranked my xj8 and moved it about 6 feet and cut it off, the next day I went to crank it and it wouldn't fire period. I tried and tried, I thought maybe a fuel pump but when researching this on the web, a guy said there was a program error it those models, I assume yours might be like mine. He said the factory reset of the computer was to be sure you battery is well charged and put the petal to the floor and hold the crank for 15 seconds, don't raise the petal from the floor, wait about 30 seconds and do it again, then while pressing it still crank again. Then let off the petal and crank normally. I was thinking this is crazy but, desperate people, and guess what the thing cranked normally and I was one happy camper for several years till my current tranmission woes, Will P good luck, worth a try.........
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Will P, 2000 Jaguar Vanden Plas, 4.0

 

That was 30 seconds not 60, I guess I'll try to edit it......

 

The problem is called bore wash, rich fuel mix on cold walls washes the oil away. It has been discussed many times, and is not exclusive to Jag V8.

 

Thanks, good to know. I'm a beginner with this.

 

Would this present itself if the car has been sitting for a few weeks without running?

Mine did the same thing, crank, crank, crank, no fire. Did a similar procedure with the accelerator pedal, and BAM fired.
Have not had an issue since. But would this be a sign of bore wash?


Thanks,
B


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Edit:
Since the car was sitting at a very slight incline, I just figured that there was air in the line from the incline and it just needed to build up fuel pressure... I have been questioning if my vehicle has become victim of bore wash...if so I will scrap the car and and buy a new one.

 

I have not seen a case of bore wash after sitting. Those who store the car for the winter would certainly report it.

More likely is the fuel pump failing.

 

You know thinking back, although I am a complete beginner, and it probably is the bore wash, the fellow on this site went into all kinds of detail about how this was a fix released at the time from Jaguar to fix the problem and possibly there might have been a computer update from dealers to fix the problem, which could be likely or there would be tons of people reporting on this. I'm not an expert, I'm just trying to get the tranny on my Green Dream on the road.. Good wishes and appreciation to all Will P

 

It's not any form of factory reset.

It's cranking but not adding any more fuel (to shift air through to clear flooded engine but also to restore compression).

You need WOT (fully wide open throttle) because that tells the PCM not to add any fuel. Near WOT will not do, as it will add yet more fuel.

 

That makes excellent sense. I wonder why they would elaborate so much. I guess that was what was told to him and so he passed it on. Thanks so much.. I much prefer science to magic. LOL Will P

 

It's useful to know about WOT cranking as it also works on many other cars (I used it on a Ford I used to own).

 

Start with the simple stuff and go back to your original thought. Check the fuse for your fuel pump. If it's burned out, you need a new fuel pump.

 

Bore wash? Never hear of that in all my years working on cars. However, I saw this in a different forum:

Bore wash usually means a condition where your fuel injection is so far out of whack that there is way too much fuel going in relative to the amount of intake air.

What happens is that naturally when the piston goes up and down, it drags some oil with it and that lubricates the bore against the piston.

Bore wash is when you have to much excess fuel that it "washes" the oil off the bore walls and so you get somewhat increased wear.

Fixing it will depend on what's wrong. Could be as simple as an air leak in the intake piping, could be as complicated as a dead ecu.

Any place with a dyno is your best bet. Running your car on a dyno will allow them to analyse the exhaust gasses to confirm if you have excess fuelling or not....then again your case may be so bad that they can just tell from looking at the colour of the spark plugs, without needing a dyno.

But if you have an issue, you usually know about it...the car will drive like a dog and there'll be black smoke everywhere

But the above condition will not cause an engine not to start, since the likelihood is only one injector has failed at full open and it will run rich. You would be able to smell the exhaust is too rich and if you ran the car for awhile, the cats would start to glow red, the CEL light would come on (and fail a smog check in the process).

In a carburetor engine, you need to step on the gas pedal a few times in order to start the engine. With my '56 Olds coming out of a long storage, I have to pour 1/3 cup of gas into the carbs prior to start or it is going to crank for a very long time. (In an aircraft carb engine, you have to pump the fuel primer a few times to inject fuel into the engine or the engine will also crank for a long time.)

I still seem to think the issue is a dead fuel pump. Try this: remove the plastic air plenum from the throttle body, pour a 1/3 cup of gas down the throttle body, put the plenum back in and try to start the engine. If the engine starts up right away then dies in 5 seconds, you know it is the fuel pump that went bad.

 

Bore wash is a common problem with the jags V8, especially with the nikasil engines if the car is started and run just long enough to move it. The rich mixture provided for starting leaves unburned fuel in the cylinders.

Just do a search for bore wash and you will find many threads.

 

I also never heard of it except for how you described, until I read it here when looking for why my XJR had 15lbs of compression.
Took a syringe of oil in each cylinder to get to fire again. Been fine since.

 

Jag owners should disregard the parts about "your fuel injection is so far out of whack".

It's usually caused on some jag V8 engines by shutting off the engine before it's up to temperature (*). There is NO implication that there is ANY fault with the fuel injection. Please don't spend any time chasing that.

(*) and usually you can do this many times without problem, which makes it seem really weird when you do suffer bore wash

 

Not being mechanically inclined as many of you guys make me glad I started this post. Sharing the various insights and theories is very helpful. I do know in my case after doing the petal to the floor and crank for so many times. I now never crank my VP for just a few seconds, I may turn the radio for a minute or so, but I have never had this problem again. For what ever the exact cause is. So I know my fuel pump works fine, but I just don't crank it for 15 seconds or so and cut it off. What is great about this site is you can learn a lot if you just follow the thread. Will P