I have a 2001 xkr convertible supercharged. The car starts up fine when it is cold. After it runs for a while Then if I shut it off and try to restart the car , it just cranks and will not turn over. I started with the cheaper option and changed the fuel filter. Nothing changed. The same issue. would anyone know in what direction I should pursue next? I love the car but it’s getting me frustrated.

 

Clarifying, the starter is spinning the engine when hot, but it isn't firing (on any cylinder?).

Start by eliminating the easiest. At the next non-start, depress the Schrader on the fuel rail and confirm you have fuel pressure. If it was running fine until you turned it off, you should have fuel pressure.

 

I'd get a can of starting fluid (ether). Take off the air filter or whatever to get some into the air going into the MAF & engine.
Give it a couple of blasts, then crank engine while hot. If it starts immediately, then you've got a fuel problem. Otherwise it's an ignition problem.
If it's a FUEL problem you're likely losing fuel pressure in the rail, when hot, due to a drippy injector. Unless you SMELL raw fuel, you probably don't have a leak elsewhere in the fuel system
Given no smell of gasoline there are
only two choices --- a drippy injector or a failed check valve on the pump in the tank causing fuel rail to depressurize, long crank to bring it back up to pressure.
If it's an ignition problem... you're gonna need a good Jaguar tech to find & fix it.
HTH

 

How long do you typically have to wait until it WILL start again? 5 mins? 20 mins? several hours?

When it won't start hot try taking the gas cap off and cranking.

 

Plug a reader in and monitor the fuel pressure, check the fuel trims. An ELM 327 or similar to work with your mobile phone.
Then you can see the real time data, and monitor the fuel ratio, and pressure whilst it is running. You might have an air leak in the intake concertina or faulty MAF sensor.
But until you have a reader, you're just guessing, you have to start with facts and work your way through them.

 

Wow, Jag/Ford's got a fuel pressure PID visible on OBD2 scan tool? I've died and gone to heaven.

 

Fuel pressure is available over OBDII only for the later 4.2 l engines as it is a key feature of the return-less fuel system.

 

Hi Joe,

A couple of possibilities come to mind. If the fuel pressure regulator (FPR) and/or the fuel pump check valve can no longer retain pressure in the rail, then as soon as the fuel pump is shut off the pressure in the fuel rail dissipates and the hot can boil to vapor. This causes the modern version of vapor lock until the fuel cools and condenses back to liquid. Connecting a fuel pressure gauge and observing the pressure when the engine is shut off hot would be a definitive way to confirm this condition, but pressing the Schrader valve stem as mhminnich suggested may be a sufficient test.

Another possibility is that if your engine coolant temperature sensor (ECTS) has failed at a resistance that the engine control module (ECM) reads as "cold," the ECM will continue to apply cold-start fuel enrichment even after the engine is hot. On a hot start, the ECM should disable fuel enrichment, but if it thinks the engine is cold, it may be choking the engine with an over-rich AFR. A stuck-open coolant thermostat can exacerbate this condition. Check the electrical connection to the ECTS to confirm it is clean and secure and the wiring is undamaged. You can easily test the DC resistance across the ECTS terminals when the engine is cold and again when it is hot to see if the sensor is responding or stuck at one resistance.

Cheers,

Don

 

Does a failed valve in the pump mean I need a new fuel pump? Or possibly..

 

A check valve can be added in the feed line between the fuel tank and fuel rail. Off the top of my head, the flexible rubber sections of the fuel hoses are 8mm outside diameter (O.D.), so check valves for 5/16 inch inside diameter (I.D.) work fine. If your FPR has failed, it would be prudent to also add a check valve, since the FPR and check valve work together to maintain pressure in the fuel rail.

 

My understanding of the earlier XKR fuel system is that it has 2 separate fuel pumps. The "second" pump is not always used as much and can die a silent death because the primary pump still works and provides fuel under most circumstance. The failed second pump is usually discovered when the primary dies and then there is no fuel at all.

I suppose the other scenario is possible too. If the primary dies the cars does not start, unless you try to start the car a number of times (6 times?), then the secondary kicks in and let you be on your way. I assume the car has to be tried 6 times again on the next start.

Have you tried to start the car multiple times to test this setup?

 

I will try it. Thanks

 

Usually I have to wait until the next morning. About 12 hours