Removed Fuel Rail.

[steve@helixcabinetmakers.]

I had an issue with cylinder 1 glow plug on CXHA engine.
Replaced all 4 glow plugs yesterday.
To try and make my life a little bit easier, I remove the fuel rail for access to the glows.
I have Carista which has a fuel system prime function.
Carista say, to be used when replacing injectors or working on the fuel system.
Tested this first and the lift pump runs for 3 minutes.
Also whilst running Carista I disconnected all 4 fuel line connectors one at a time.
I have fuel going to the high pressure pump and back to the tank and in and out of the filter.
From what i know the high pressure pump is driven by the cambelt.
Does the fuel rail and high pressure pump need to be primed before cranking the engine.
At the moment the engine will not start and i am worried about damaging the high pressure pump.
Does VCDS do more than just run the lift pump.
If anyone can help it would be most appreciated.
Thankyou.

 

[Dellmassive]

Get any further with this?

 

[steve@helixcabinetmakers.]

Hi, I checked the fuel rail pressure yesterday and when the engine is off it only shows 100kpa and cranking it goes between 55000 and 35000kpa.
Could this mean the fuel rail pressure control valve is stuck open.
Thanks for getting touch.

 

[Dellmassive]

Have a look here re rail pressure

Post in thread 'Cold start problem' Cold start problem

.

 

[DXX]

Hi, I checked the fuel rail pressure yesterday and when the engine is off it only shows 100kpa and cranking it goes between 55000 and 35000kpa.
Could this mean the fuel rail pressure control valve is stuck open.
Thanks for getting touch.

Have you bled the injector lines at the tube nuts while cranking?
It sounds like you are compressing air when cranking.

 

[steve@helixcabinetmakers.]

Thanks for the replies, and thankyou Dellmassive for the interesting read.
Basically removed the rail by disconnecting left side sensor, this allowed me to rotated the rail through 90 degrees.
Changed the glows.
Refitted the rail, primed the system by activating the lift pump and cracked open the injector nuts.
Cranked over the engine until i had fuel at the injector nuts.
Tightened injector nuts and cannot get it to start.
So yesterday i checked the fuel high pressure deviation. Ignition on 196 Bar, cranking it goes all over the place + or - 150bar.
Fuel high pressure 4 bar, guessing this must be the tank pump as it goes on and off with ignition.
Is the fuel high pressure deviation controlled by the fuel rail pressure control valve.

 

[Nam600]

You can also take the rubber return pipe off the rail. The one next to the pressure regulator valve which has a connector at a right angle to the rail. Block the rubber pipe with a bolt and jubilee so you don't get any fuel coming back up from the rest of the system. Then put a temporary pipe on fuel return connection on the rail and lead it to a bowl or some sort of bottle. Now when you Crank the engine you can see if its allowing fuel past the regulator which will tell you if its leaking or not. Could be faulty or some dirt/debris stopping it from sealing.

 

[Nam600]

Item number 8 in the below illustration. Is that what you removed to rotate the fuel rail?

 

[steve@helixcabinetmakers.]

Thankyou, will try and see what happens.

 

[Nam600]

So did you remove the item ~8 on the illustration? If so, it says in the manual that it has a deforming sealing lip and that the pressure regulator must be changed for new after removal. I guess that's because the seal is a use once only type. The manual also says the pressure sensor mounted on the left of the rail has a deformable sealing lip but seems to state the sensor can be reused. No idea why.

Try the leak off test I described and then reset all learned values. (Manual says to do this but I think that's because it is expecting you to use a new pressure regulating valve and needs to relearn as it will be slightly different in opening an closing values)

01 - Systems capable of self-diagnosis , 01 - Diesel direction injection and preglow system EDC 17 , 01 - Engine electronics functions , 01 - Resetting engine electronics learnt values .

 

[Nam600]

Reason I ask is that I think the sealing surface as shown by red arrow below, could have been damaged or got dirt in it when/if you removed the regulator. This would allow fuel to leak past and go straight out the fuel return. It does not take much of a leak to lose fuel pressure when the pressure is trying to raise to 400 up to 1000bar.

 

[steve@helixcabinetmakers.]

Thanks for all the help and no i didn't remove the pressure regulating valve or fuel pressure sender.
Haven't tested yet but kind of thinking the regulating valve could be my problem.

 

[kasperh]

did you found a solution? i did this yesterday to and wondering whats the problem

 

[lassie]

Hello All,

I have the same problem as @steve@helixcabinetmakers.

I have changed the glow plugs, and now the engine won't start. Probably because of the removal of the fuel rail.
Changed the pressure regulation valve also nr.8 on schematic but no start-up yet.
Also we have a professional diagnostic tool to calibrate this regulation valve, but nothing changes..
Primed the system so many times, bleed all the air out the system ...
Vehicle 3weeks abdonned right now.. please help !

Dries VB
Belgium

 

[DXX]

After priming the low pressure fuel line with Carista are you cranking the engine when bleeding the high pressure side?
The HPFP is a positive displacement pump, it has to turn to fill the HP fuel system including rail, HP pipes and injectors.

 

[kasperh]

Hello All,

I have the same problem as @steve@helixcabinetmakers.

I have changed the glow plugs, and now the engine won't start. Probably because of the removal of the fuel rail.
Changed the pressure regulation valve also nr.8 on schematic but no start-up yet.
Also we have a professional diagnostic tool to calibrate this regulation valve, but nothing changes..
Primed the system so many times, bleed all the air out the system ...
Vehicle 3weeks abdonned right now.. please help !

Dries VB
Belgium

I got mine started, you need to make high rpm to get high rail-pressure. I used starting-spray and held engine at 3000-3500rpm and opened the pipes at the injectors, one by one. Do this with electric plugs connected.
I did this method maybe 8-10 times and it finally fired on all 4 cyls.

 

[DaveD]

Have you bled the injector lines at the tube nuts while cranking?
It sounds like you are compressing air when cranking.

Good advice, then.

 

[DXX]

Good advice, then.

Yup, ‘puters and dongles don’t fix everything. Not yet anyway

 

[lassie]

Fixed , Sloved !
Hello, thank you all for the good information !
How we did get the T6 runnnig:

Removed the rail sensor. (this to increase rail pressure +300bar and also this automaticly open and close the injectors)
At the same time, opening the nuts from the pressure lines to the valves.
By these 2 things the possible stuck air could breed out of the system.


Thank you again all !

Dries VB