Hi,

I recently purchased a 1994 XJS 4.0 with 84,000 miles. Here is my problem, I have put around 2,000 miles on the car and it runs great (once I get it started) Sometimes I have to crank the car multiple times, once it fires it idles and runs great. It seems to start harder when it is sitting with the nose uphill. When I crank it if it doesn't start within 2-3 seconds you can release the key and try again and it will fire right off? Any ideas or suggestions will be greatly appreciated.
thanks
Tracy

 

I would start with a fuel pressure reading. Sounds like you may lose fuel pressure as the car sits.

 

I haven't tried that because it smokes as if it is flooding itself? I assume that would eliminate the fuel pressure being in question? It can be driven for an hour and cut off immediately restarted and it is fussy. It starts after sitting overnight almost better than just cutting the engine off and re-firing? Is there any control such as an engine run sensor, etc to check?

thanks
Tracy

 

Could be the fuel pressure regulator.

 

Ok, any idea where that is located?
thanks
Tracy

 

It's at the end of the fuel rail. It will have two lines that screw on and a vacuum that pushes on.

 

This sounds very similar to the current "performance" on my 92 V12.

It will not start (or very rarely starts) on the first crank, but it always starts easily on the second crank. My mechanic ran various fuel rail pressure tests and the results clearly showed that I lose my fuel pressure as soon as the fuel pump turns off when I turn the car off. We isolated the problem to be the shut off valve which on my car is inside the fuel tank on the fuel pump itself. This shut off valve is supposed to close as soon as the fuel pump stops to maintain pressure at the fuel rail, but mine isn't working. Apparently it's a common issue. When my car was at my mechanics it was sitting beside a beautiful 20k mile 1996 6.0 V12 car with exactly the same problem :-)

My start up sequence is now.....

1) Get in the car and turn the igntion on (This runs the fuel pump briefly for a few seconds)
2) Put my seat belt on, set the radio and aircon, check my hair :-)
3) Turn ignition off then on again..... and listen for the fuel pump start then STOP running. As soon as I hear the fuel pump STOP running I crank the car and it starts instantly.

This is an acceptable work around for me right now but in future I will need to do other things around the fuel tank (sender guage doesn't work correctly) so I will replace the shut off valve at that time

 

Thanks for all the help. My father has a XJS Convertible also. His starts well. I swapped out the fuel pressure regulator and his still starts well and mine does not. I have tried bumping the fuel pump and it doesn't seem to help. In the mornings the car will start OK. It cranks longer than it should but starts on the first try. After warm It takes 4 to 5 cranks and seems to be getting worse. Once it does fire it smokes quite a bit like it is flooding itself. It is like flipping a switch when the car does fire, it is ready to go. Now I am wondering if I am wasting my time changing the fuel pump? Any more ideas would be greatly appreciated.
Thanks
Tracy

 

Ok,

I spent the day trying to figure out this demon. What I have found out so far is that it is NOT in the fuel delivery. A mechanic friend of mine checked the car out and found that the car is not getting fire from the coil when you first start cranking. As soon as it gets fire the car starts. I put a new coil on it but it does the same thing. Anyone know if this could be in the switch or something else?
thanks
Tracy

 

1994 XJ6 manufactured 11/93 . Recently purchased my first Jaguar, I am having same problem. At first attempt to start, car acts like it is not getting spark second attempt 99% of the time is successful. Considering that a fuel starved engine shares the same characteristics as a engine with no spark.
I have replaced fuel pump, distributor cap, rotor, wire set, K&N air filter. My next attempt to remedy this problem is to acquire a second fuel pump, I intend to add a in line external fuel pump tomorrow. I also plan to make sure the in tank fuel pump relay is exactly what JAGUR specifies.

 

I have the same starting issue with my 94 xjs L6. I notice there was a TSB on the fuel pressure regulator on this car.

Also, if the problem is with the shut off valve. Maybe it is possible to add a second external fuel shut off valve as the older xjs has: 1978-1979 Jaguar XJ12 Fuel Solenoid - OE Aftermarket W0133-1615890

 

My 85 xjs HE has a similar problem. Today i drained the gas tank via the plug under the trunk and took out about 5 gallons of murky looking gas and oil. I can't believe the car was running period with that fuel, and it ran great after it got started. I won't be able to say if that fixed my problem for sure until i drive it for a while, but it sure couldn't have hurt.