No fuel rail pressure

peedy17 · Nov 6th, 2021, 13:48

Hi all,
Can’t get my XC90 to start after recent repairs. I’ve had the HP fuel pump off and refitted. Now my fuel rail is reading 0kpa and goes to 230kpa when cranking. Straight back down to 0kpa once I stop cranking.

If I unplug the fuel rail pressure sensor it shows 180000kpa so I think that’s working fine. Surely If its showing 0kpa then the fuel pump would try and pressurise it?

I’ve even taken all the injector pipes off the common rail and blanked the outlets off and it still won’t pressurise.

Sounds like a pump issue to me.

Any ideas?

Thanks

peedy17 · Nov 6th, 2021, 18:23

I can get it up to a solid 450kpa and up to 650 when cranking. Am I right in thinking it should be around 20000kpa?

Clan · Nov 6th, 2021, 21:16

Quote:

Originally Posted by peedy17

I can get it up to a solid 450kpa and up to 650 when cranking. Am I right in thinking it should be around 20000kpa?

yes you are right should be 20,000 cranking to start
Is the fuel leaking back through the injectors back to the tank?
take off the little rubber pipes from the top of the injectors and see if any fuel comes out of any of them when cranking...

5cilinder · Nov 7th, 2021, 01:25

Start checking the resistance of the railpressure sensor and regulator AND the wiring of the crappy connector of the railpressure regulator (on the end side to the right of the pressure rail) , had this problem myself due to a intermittent loose wiring in the connector

cheshired5 · Nov 7th, 2021, 09:34

Is the in tank pump working?
If you've opened up the fuel system for repair and the tank pump is dead, it won't start in a million years as nothing will send the fuel to the engine and prime the system.

Because of my dead tank pump, I have to :
1. Treat a quarter of a tank as empty and fill before.
2. Manually bleed and prime the fuel system if it runs out of fuel.

peedy17 · Nov 7th, 2021, 11:00

Yeah pump is working. Has a decent flow into the HP pump.
I’m going to carry out continuity checks on the sensors today as mentioned. Hopefully that throws something up.

I also had the starter off and only getting about 200rpm on cranking. Is that enough?

cheshired5 · Nov 7th, 2021, 11:28

Quote:

Originally Posted by peedy17

I also had the starter off and only getting about 200rpm on cranking. Is that enough?

Yes plenty. That rpm should easily generate 5000+ psi on a working system. Well over the minimum 2000 psi so the starter isn't the problem.

peedy17 · Nov 7th, 2021, 12:12

Ok thanks,

I’ve got a replacement pump and sensors coming tomorrow to try swapping them out too

peedy17 · Nov 8th, 2021, 15:49

All sorted guys, new HP fuel pump worked. Thanks for all your help

Nov 6th, 2021, 13:48	#1
peedy17 Junior Member Last Online: Apr 17th, 2024 18:33 Join Date: Oct 2021 Location: Stockton-on-tees	No fuel rail pressure Hi all, Can’t get my XC90 to start after recent repairs. I’ve had the HP fuel pump off and refitted. Now my fuel rail is reading 0kpa and goes to 230kpa when cranking. Straight back down to 0kpa once I stop cranking. If I unplug the fuel rail pressure sensor it shows 180000kpa so I think that’s working fine. Surely If its showing 0kpa then the fuel pump would try and pressurise it? I’ve even taken all the injector pipes off the common rail and blanked the outlets off and it still won’t pressurise. Sounds like a pump issue to me. Any ideas? Thanks

Nov 7th, 2021, 01:25	#4
5cilinder Premier Member Last Online: Apr 22nd, 2024 15:09 Join Date: Oct 2011 Location: Groningen	Start checking the resistance of the railpressure sensor and regulator AND the wiring of the crappy connector of the railpressure regulator (on the end side to the right of the pressure rail) , had this problem myself due to a intermittent loose wiring in the connector Last edited by 5cilinder; Nov 7th, 2021 at 01:31.

Nov 7th, 2021, 09:34	#5
cheshired5 Premier Member Last Online: Dec 26th, 2021 13:42 Join Date: Dec 2013 Location: Crewe	Is the in tank pump working? If you've opened up the fuel system for repair and the tank pump is dead, it won't start in a million years as nothing will send the fuel to the engine and prime the system. Because of my dead tank pump, I have to : 1. Treat a quarter of a tank as empty and fill before. 2. Manually bleed and prime the fuel system if it runs out of fuel. __________________ 2002 S60 SE D5 Manual 209000 miles

Nov 6th, 2021, 18:23	#2
peedy17 Junior Member Last Online: Apr 17th, 2024 18:33 Join Date: Oct 2021 Location: Stockton-on-tees	I can get it up to a solid 450kpa and up to 650 when cranking. Am I right in thinking it should be around 20000kpa?

Nov 7th, 2021, 11:00	#6
peedy17 Junior Member Last Online: Apr 17th, 2024 18:33 Join Date: Oct 2021 Location: Stockton-on-tees	Yeah pump is working. Has a decent flow into the HP pump. I’m going to carry out continuity checks on the sensors today as mentioned. Hopefully that throws something up. I also had the starter off and only getting about 200rpm on cranking. Is that enough?

Nov 7th, 2021, 12:12	#8
peedy17 Junior Member Last Online: Apr 17th, 2024 18:33 Join Date: Oct 2021 Location: Stockton-on-tees	Ok thanks, I’ve got a replacement pump and sensors coming tomorrow to try swapping them out too

Nov 8th, 2021, 15:49	#9
peedy17 Junior Member Last Online: Apr 17th, 2024 18:33 Join Date: Oct 2021 Location: Stockton-on-tees	All sorted guys, new HP fuel pump worked. Thanks for all your help

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