We have a 1998 Jaguar XJ8 with about 50,000 miles. I recently posted about a condition that every once in a while the car loses power and stalls. Pull over to the side of the road and it fires right up with no problem. This has happened about 4 times over the last 2 months. Recently the car has become very hard to start when sitting for more than a few hours. If you don't touch the throttle and start cranking, the engine gets to the point where it fires and as soon as you let of the key it stalls. I have found that the only way to start it is to floor it and when it fires let it rev up to about 2000 rpm momentarily and it runs fine. It usually gives a puff of blue/black smoke. I listened for the fuel pump before cranking and it sounds like it is working. I tried to find the schrader valve on the fuel rail like on the old XJ6 but I could not even find the fuel rail . It is my wife's car and I don't like the idea of her being stranded somewhere. If any of the great minds here can help I will be very thankful.

Does anybody know a reliable jaguar mechanic in the Vancouver BC area. I have heard horror stories about the dealer here.

 

Take a look at Service Action S514 in this link:

https://www.jaguarforums.com/forum/s...ad.php?t=25334

The stalling while driving and restarting is a direct symptom of the throttle body issue addressed in that SA. Can't comment on the other issues.

The free replacement of affected TBs has been extended until the end of this year.

 

The car has not stalled while driving for a couple of weeks now (fingers crossed). I checked with the dealer and this car had the upgraded throttle body in 2004 about 15,000 miles ago.

Now the car is an absolute bear to start if it has been sitting a long time. In the morning or after work when it has been sitting for 8 hours. If we drive the car at lunch it starts normally and again after work no problem.

I am thinking the fuel pressure is leaking down,but then I turn the key on and wait 20 - 30 seconds for the fuel rails to pressurize and it does not help. The only way to start the car when cold is to hold the throttle to the floor and crank it. When it starts it races to about 2000 rpm and it drives fine. If it isn't raced up a bit on start it cranks until it catches but immediately you let the key go it stalls.

Any thoughts.

 

Complete guess but cars or your era were famous for fuel management problems leading to excess fuel in the cylinders. The excess fuel washed down the oil on the cylinder walls and the result was loss of compression. Mostly attributed to short drives but my uninformed opinion is that there were other issues involved.

 

Part load breather needs to be cleaned also. If battery is weak, slight extended crank will cause fuel dump and flooding.
Failing tensioners is also a contributing factor to hard starts.
Fuel pump check valve sticking can also cause fuel to drain back to tank but will only cause extended crank for about 5 seconds while pressure builds.
Leaking injectors also.

 

I purchased a proscan reader but could not get ot to work. I finally got it stated and took it to a Jag mechanic. He read the code and replaced a crank sensor. It has started perfectly since.
Thanks for all the replies.

 

Thanks for the feedback!

 

If you have random stalling be sure to check the two knock sensors on the top of the engine. I replaced one of mine which was covered in cracks and the car has not stalled once since! I had tried everything else; checked all the connections and the relays, everything seemed to be in order so I was very stumped, until I noticed the sensor was quite cracked from the years of heat.