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I apologize for borrowing someone's picture from the forum. There is an older long thread on replacing the fuel pumps. They mentioned there would be a later post with a part number for the check valves. Haven't seen it. My 04 XJR takes a long time to start, giving all the symptoms of no fuel. 54psi fuel pressure from live data while running. No codes and no issues with full throttle. This leads me to thinking the check valve has failed, draining the fuel rail between starts. Rather than try to fit an aftermarket check valve in the tank with all the plastic fuel line and connectors, I'm thinking of putting one in the line to the fuel rail just before the pulse damper. Not sure of wisdom of this, but right or wrong, I think I'm going to try it. Can always take it out. Any thoughts?
Wow....as it happens yesterday I was just reading through the 180 page technical training on the powertrain systems 810-Jag Engine Management and Diagnostics .....
Yeah I know, have I got nothing better to do?
In my defense it was a slow day and I am keen to obtain a better understanding of how the engine is managed, as I haven't had my XJ8 too long and I am still on a relatively steep learning curve.
Anyhoo..........I took note when I read that the crank position sensor will give this long crank effect you are seeing if the ECM does not detect correct CPS signals, it must crank longer to determine engine position. Refer to the last paragraph of the below exert.
I also attach the information about the check valve operation of the returnless fuel system we have in our cars.....just for good measure ;-)
Thank you, Mark. That was the first thing that crossed my mind and I have a new one sitting on my desk right now. However, yesterday I installed the check valve between the surge damper and fuel rail and problem solved. Several hot starts and 2 full throttle runs through second gear and no issues. I will read your post thoroughly and probably replace the CPS anyway next time I have the car in the air. Thanks again for the suggestion.
Fuel Pump Check valves
