Hi .. hope someone can help..
2004, manual, 40k miles..
So the car will start great 50% of the time, or not start at all. Once running, will always run great..
Seems like the odds are same hot or cold..
When it doesnt want to start, I can crank it for a long time, (with only *rarely* a hint of fire in one cyl.. not like an injector issue )

I replaced CPS(bosch , crank ps, and just now the RCM.. no improvement.
It definitely sounds electrical to me.. maybe the (replaced) security module is acting up.. can it fail like this?

please help!!!
TIA

PS. no CEL, no codes

 

I think you need to invest in a fuel pressure gauge and watch it while starting. Can you hear the fuel pump prime when you first turn the key to on?

James

 

Yup, sounds like you have covered most of the bases, except fuel pressure.

 

I agree, quite possibly a fuel pressure issue.


.

 

It seems unanimous that fuel delivery is the next thing to investigate. We just replaced the fuel pump in our 2004 Limited coupe to solve a hard starting issue that seem to happen more when the engine was warm. Ours has 37,000 miles on it and we had already replaced the fuel filter with a new BOSCH unit. I would recommend a BOSCH fuel pump but they run about $150 so I went with an off brand auto top one with good reviews on Amazon for $45. It seems the check valve in our fuel pump was not working properly to maintain system pressure when the engine was turned off.

 

hi all, thanks for all the suggestions.
Happy to own a nice 'professional, made in china' fuel pressure gauge set.. doesnt look that bad actually, for the price..
Anyway.. whether I crank/no start or it starts, the pressure in the rail is steady 58 psi..

never stutters at speed, feels like it has full power.. so makes sense that fuel pressure is OK, but now I know for sure..
what next? ideas? TIA

 

At a loss now. I cannot think of anything else that you haven't already tried. Maybe someone will come in and provide that 'Ah haa' moment? Sorry... Good luck!


.

 

So the car does not start, do you keep cranking it over until it starts or what?
Does it just suddenly start after not starting or do you leave it for a while or what?

 

Once you do get it started does it hold 58 psi when you turn the engine off?

 

I have the same problem with my 04 XF. I have to get it jumped each time it won’t start. I get nothing, no click, nothing. It’s not working this very minute. Had it jumped twice this week. I replaced battery twice this year. I LOVE my XF and I want to keep it and drive it everyday🤩 Please help, it runs like a champ when it runs. Very smooth

 

It sounds like you don’t have the same problem but instead a very different problem. Your problem sounds much more like a battery drain issue if you have to have it jumped and have replaced the battery more than once. If it starts when jumped you would likely need to track down what is draining the battery. There are multiple threads detailing how this procedure is done with a couple currently going through it or having recently solved their issue. There are various causes which all result in a dead battery so testing and narrowing it down to a specific fuse seems the best course of action.

 

Sounds to me like one particular relay inside the RCM is beginning to die. RCMs for these cars are like ballast resistors and points were for cars of old. You carry a spare in the glove box.

 

And / or the siren if you have not disconnected or replaced it?

 

Thank you for taking time to help, much appreciation😊