Bmw x5 just wont start

,

Good afternoon all first time poster,
So hello all…

So as the title suggests iv got a x5 2004 plate (e53) that just won’t start, it cranks perfectly fine.

So just sit back and enjoy the little story.

The car was running perfectly fine then it just cut out without any warning (was in the drive just ticking over), so stuck the obd reader on and was getting fuel rail pressure low.
And so the jobs began

Checked all fuses and relays
I replaced the fuel filter
Then i replaced the fuel pump (under the passenger seat)
Then replaced the common fuel rail pressure sensor
Then done a leak back test (all fine)
Crank and cam sensors are both fine
And now iv recondition the high pressure pump

Couple thinks i should mention the old obd isn’t pucking up any error codes now

So now im at a complete loss on what else it could be, has anyone got any other ideas before i start pulling my hair out and cry

Thanks

Might want to replace the crankshaft position sensor (CPS). when they dies, they won’t set a code and won’t start. You can test this theory by spraying some starter fluid into the intake while someone tries to start the car. If it fires and runs for a moment, it isn’t the crank sensor, it is still a fuel problem. If it still refuses to start, that points to the CPS.

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Unlikely that the OBD will set any codes until the car starts and most require that it be warmed up. Would bet that low fuel pressure code was there prior to stalling. Agree with Mustangman that the CPS would be the first suspect when car stalls without warning. How did you verify that it was OK? Presume that this is a 3.0 liter?

Sorry should of said we’ve tried give her some spray and still a no go it runs but soon as you take the spray away it just dies

Is this a diesel?? Or direct injection petrol engine?

Based on your post, you still have a fuel delivery problem.

Yes mate its a 3.0 diesel, i put a ohm meter across the terminals and checked the readout and all was fine

Have you checked to see if the injectors are firing?

Iv done a leak back test and checked the wiring to the injectors and everything seems to be working fine

The common fuel rail is reading 300 psi
If thats of any use to know

The wiring is OK but are the injectors actually being commanded to fire? There may be a fuse specifically for those direct injectors, not sure.

Sorry when i say iv checked the wiring iv connected a old school analog voltage tester and the needle pulses when cranking

You mentioned 300 psi as the rail pressure… is that the lift pump pressure or the high pressure for the injectors? If it is the high pressure sensor, that should be far higher. Even 300 Bar is low for a common rail diesel. That would be a problem.

300 Mpa, would be more likely. If that’s what you are seeing… You’ve gone beyond my knowledge of common rail diesel engines. Sorry, that’s all I have. Might be time to… gulp… take it to a BMW specialist shop.

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Yeah think your right 300 mpa well thats for your help mate

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So iv double checked the rail pressure and it is only at 300 psi, whats else could be causing the low pressure

Hi Jamie you should have around 3600psi (250bar)at the common rail when cranking, if your not getting that the first thing I’d try is unplug the rail pressure sensor, this should give you a default pressure that will start the engine. If that doesn’t help make sure you have pre supply pressure and volume from the in tank pump at the clear fuel pipe at the high pressure pump ( about 3to 3.5 bar) if you don’t have either Pressure or volume you have a blockage somewhere. If I remember right ( I’m a BMW tech but we don’t see many E53s these days) they have a return to tank line near the filter that plays up. Hope that helps, if you need any specs or further help give me a shout👍