I never had a problem starting this car. I let it sit for a month, then I started it to charge the battery. I let it idle for about 40 minutes. When I shut it off, I could not get it started the next day. The engine cranks. I changed the fuel filter and checked the fuel pump by pumping fuel into a jar from the fuel line. It pumped about 6 ounces on each cycle. I also can hear the pump cycle when I turn the key. I thought I may have pumped some water into the fuel lines from the tank, I added dry gas and injector cleaner. I was able to get it running one day by pumping the pedal several times which I never had to do. Could the pump be working partially or sporadically? Any thoughts would be appreciated.

Have you checked the battery voltage? Check and clean the terminals. The altenator will not charge a battery in itself. The altenator is used to run the electrics of the car and maintain charge in the battery. Used to be you could run a car for 45 mins. and charge the battery. You need a minimum of 9 volts to turn on the computers to run the car. Does the fuel smell good? Check plugs for fouling. If fuel smells different or not real odorous, it can foul plugs. Check for spark. Air, fuel, fire. The newer Jags and their security systems can run down a battery pretty quick if sitting over a week. If battery is over 4 years old and in a cool climate, would be time to change.

Take a look at:

www.jaguarforums.com

You will find a valuable source of information regarding Jaguar.

brdave

The battery is relatively new and is reading 11.90 volts on a tester. I disconnected the fuel rail connection and fuel is pumping to the fuel rail. I am surprised though that the plugs are dry even though the fuel rail is getting 6oz of gas on each key cycle. I don't see how the injectors could all be blocked. I am going to check the spark ignition once I get an inline spark plug tester long enough to reach down into the plugs. I checked all the fuses dealing with the injectors and pump and they all are ok. I am really baffled. One question I have is about the injector tops where the two wires lead into them. Do the tops unplug from the injectors below the bracket holding them in place. Do the tops pop off, because I have seen small light testers for the injectors which light up when plugged into them if they are working. I could borrow the appropriate size ones off my local mechanic friend. Is this a good idea? Thoughts?

Usually a metal clip that needs to be undone, then plug your injector test light in (and I still have one of those, somewhere).
Fuel FLOW is one thing, fuel PRESSURE is another.
You need PRESSURE or the injectors will not work.
There is a spec, and it HAS to be in that range.

If your pressure relief valve is stuck wide open, it's all going back to the tank.

Usually, and don't recall on Jags, one leg of the injector plug is ignition-switch "hot", the other grounds through the ECU to toggle the injectors.
If your main fuse for injectors is out, or corroded, you won't have any power to ground on the other side!

As someone cranks it, with a hand on a couple of injectors, you should feel them clicking if they are getting signal.

If they are, most likely with dry plugs it's pressure related.
If not, either power to or grounding from the injectors.

Battery still low, 11.9 not 12.75+ as it should be. You can insert a noid light and check firing of injectors. Fuel guage will show real pressure values. Some of these XJ40s will get low on compression, check compression and if low squirt oil in cylinder to increase compression enough to start. Check crank sensor and cam sensors these will cause no starts. The ignition amplifier is by the distributor on the right side fender, test it also.

Yeah, but Larry, the plugs are dry.
If the injectors are firing and he has pressure within range on the fuel line, the plugs should be at least damp.

Here are a couple of things to check. Research "crank sensor". If the crank sensor fails, (not uncommon in XJ40s, not sure about X300s) the injectors will not fire. Second, get out your owners manual and look up "Inertia Switch" Find it, and check to see if it was tripped. If you are not sure, trip it and re set. It will be fairly obvious when you see it. There is a plunger on top. Pull it up, and push down to re set.
Finally, take a sample of the fuel from the rail, into a clean clear container. Wait a whiule for it to settle, and look at it for color and clarity. If there is water in it, it will settle to the bottom.

Here are a couple of things to check. Research "crank sensor". If the crank sensor fails, (not uncommon in XJ40s, not sure about X300s) the injectors will not fire. Second, get out your owners manual and look up "Inertia Switch" Find it, and check to see if it was tripped. If you are not sure, trip it and re set. It will be fairly obvious when you see it. There is a plunger on top. Pull it up, and push down to re set.
Finally, take a sample of the fuel from the rail, into a clean clear container. Wait a whiule for it to settle, and look at it for color and clarity. If there is water in it, it will settle to the bottom.