Remove fuel line Citroen C6 2.7 HDI V6

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cit-rotti
Donor 2020
Posts: 6
Joined: 07 May 2020, 09:19

Remove fuel line Citroen C6 2.7 HDI V6

Unread post by cit-rotti »

Hi,

After the pre-delivery pressure in front of the diesel filter - should be between 0.5 - 0.6 bar - is only 0.38 bar with this Zitroenen crate, I am considering changing the first stage of the fuel lines from the pre-delivery pump to the first connection point, because in this part there is a connection flow / return with integrated pressure reducer (spare part 1525 PK with regulator).

This pressure reducing valve (regulator) reduces the pressure of the pre-feed pump, which delivers more than 2 bar to this reduced pressure.

Lt. Service documents for SID 201, the vehicle can no longer be started at a pre-delivery pressure of 0.3 and less.

There are 3 connections (flow / return / Eolys) on the pre-feed pump - provided there is no original additional heating.

The next connection point - forward / reverse under the vehicle - is not a problem.

After the feed pump, the lines first go down in a 90 degree bend - and there is the no longer visible connection flow / return with this integrated pressure reducing valve and its holder. This valve also has a connection to the atmosphere - like ??. - and only then in a further 90 degree bend to the front.

Has anyone already removed this pipe section?

If so - the tank has to be lowered - or is there a removable cover - or or ...?

Greetings Wolfgang

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GiveMeABreak
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Re: Remove fuel line Citroen C6 2.7 HDI V6

Unread post by GiveMeABreak »

Hi Wolfgang, wie geht's?

Not sure if this will help you, but a bit of info in case. Info on checking the low pressure fuel side at the end.
Wolf A.PNG
Wolf A.PNG (142.43 KiB) Viewed 46 times
(16) Fuel filter.
(17) Sensor for presence of water in diesel fuel.
"d" Aperture not used.

Direction of fuel circulation (as per arrows):
"b" Fuel inlet: The fuel comes from the tank and from the thermostatic valve when the engine is cold (click-fit connection).
"c" Fuel outlet: Towards the fuel high pressure pump and the tank return pipe (click-fit connection)
High Pressure Fuel Pump
Wolf B.PNG
ReferenceDesignation
eFuel inlet into the transfer pump
fFuel outlet from the high pressure pump towards the fuel high pressure common rail
gFuel return from the high pressure pump towards the fuel tank
(18)Transfer pump
(19)Fuel pressure regulator
(20)Fuel volume regulator
Operation Phase
  • The engine management ECU checks the pressure of the diesel fuel in the fuel high pressure common injection rail in a closed loop via the fuel pressure sensor.
  • The engine ECU uses the fuel pressure regulator (1322) to manage the pressure of fuel inside the fuel high pressure common injection rail.
  • The engine ECU pilots the fuel volume regulator by sending a modulated power of the form of OCR.
  • If the OCR signal is small, the fuel volume regulator allows a large quantity of fuel to go towards the fuel high pressure pump.
  • If the OCR signal is big, the fuel volume regulator allows a small quantity of fuel to go towards the fuel high pressure pump.

Wolf C.PNG
ReferenceDesignation
eFuel inlet into the transfer pump
fFuel outlet from the high pressure pump towards the fuel high pressure common rail
gFuel return from the high pressure pump towards the fuel tank
(4)high pressure fuel pump
(18)Transfer pump
(19)Fuel pressure regulator
(20)Fuel volume regulator
(21)Filter internal to the fuel pump
(22)Outlet valve of the pumping component
(23)Lubrication valve
(24)Inlet valve of the pumping component
(25)Pressure regulation valve
Transfer pump (pre-supply)

The transfer (pre-supply) pump is a volumetric pump integral to the fuel high pressure pump.
The absolute pressure is between 0,7 and 1,5 bars as the fuel enters the transfer pump.
Wolf D.PNG
"e" Fuel inlet into the transfer pump.
"f" Fuel outlet from the high pressure pump towards the fuel high pressure common rail.
"g" Fuel return from the high pressure pump towards the fuel tank.
(5) High pressure fuel sensor.
(19) Fuel pressure regulator.
(20) Fuel volume regulator.
Fuel Low Pressure Side Check

Tooling:
wolf E.PNG
wolf E.PNG (25.84 KiB) Viewed 46 times
Wolf F.PNG
Wolf F.PNG (22.89 KiB) Viewed 46 times
Ø 10 mm union for low pressure plug 4215-T. Ø 8 mm union for low pressure plug 4218-T.
Wolf G.PNG
Wolf G.PNG (59.76 KiB) Viewed 46 times
Wolf H.PNG
Wolf H.PNG (64.58 KiB) Viewed 46 times
Pressure gauge for checking the turbocharging pressure 4073-T.A (kit 4073-T).[4] Extension 4251-T.
Wolf I.PNG
Wolf I.PNG (296.85 KiB) Viewed 46 times
Connect the tool [1]between the booster pump and the fuel filter (white marking on the fuel supply pipe).
Connect the tool [2]downstream from the diesel injectors, between the high pressure fuel pump and the fuel filter (green marking on the fuel return pipe).
Connect tool [3]on tool [1]or on tool [2].

CAUTION: Any pressure checks downstream of the fuel filter are prohibited.

N.B.: For dynamic testing of pressures: insert the extension [4]between the pressure gauge [3]and tools [1]and [2].

Pressure values (Statically)
The low-pressure fuel circuit is fitted with a fuel pump and a fuel pressure regulator.
The fuel pressure regulator authorises a maximum pressure in the fuel circuit of 0,7 bar.

Switch on the ignition.
Fuel feed pressure shown by the pressure gauge [3] = 0,6 bar.
Start the engine.

N.B. : When the engine is started the pressure value indicated by the pressure gauge [3] is 0,65 bar then stabilises at 0,5 bar.

Fuel pressure indicated by the pressure gauge [3] (During normal operation
Engine speedFuel feed pressureFuel return pressure
Idling0,5 bar0,3 bar
Accelerated (At 3000 rpm)0,3 bar0,8 bar

cit-rotti
Donor 2020
Posts: 6
Joined: 07 May 2020, 09:19

Re: Remove fuel line Citroen C6 2.7 HDI V6

Unread post by cit-rotti »

Hello and
thanks for technical documentation with the tool pictures.
It's about the low pressure fuel circuit
I have the tool for measuring (built by myself).
Instead of 0.6 bar at idle, I only have 038 bar there.
The low pressure fuel circuit is equipped with a fuel pump and a fuel pressure regulator.
The fuel pressure regulator approves a maximum pressure in the fuel circuit of 0.7 bar.
This low pressure fuel regulator is installed after the pre-feed pump in the tank - between the flow and return and can probably only be removed completely.
Greetings Wolfgang

cit-rotti
Donor 2020
Posts: 6
Joined: 07 May 2020, 09:19

Re: Remove fuel line Citroen C6 2.7 HDI V6

Unread post by cit-rotti »

Hi
... Thanks for the information.
According to my measurements in the "fuel supply pressure", the pressure is always 0.38 bar when the ignition is on, at idle and at higher engine speeds.
My guess is therefore that this pressure reducing valve only works as a bypass but no longer really regulates.

This 2.7 HDI engine with the injection components (SID201) is also installed in the C5 / Analog in the Peugeot.

My question was in the first place - whether the spare part 1525PK can be replaced without lowering the tank - at Certus the thing costs just under € 80 - I own a used one (not tested).
I was hoping that someone else had already done this work and reported about it.
Greetings Wolfgang