P1210 fuel pressure regulator fault

[Rhothgar]

Thanks. Nice to see it is legible...

[Rhothgar]

On my engine, 1208 appears to be either the diesel thermistor or 3rd piston deactivator. Cannot recall from memory.

I may have to bow out gracefully from this diagnosis for today at least.

Darbuck.

Here is the component list for a C5 from the Forum Wiki. Marc may well be able to verify if this is correct for your car. There does not appear to be cross-referencing with the component codes between one model and another model ie Xantia and C5

https://frenchcarforum.co.uk/wiki/List_ ... 2_to_2695)

[GiveMeABreak]

DW10BTED4

High Pressure Pump

Marking	Description
(4)	Transfer pump (pre-supply)
(5)	Hydraulic head
(6)	Venturi (Incorporated in the high pressure pump)
(7)	Pressure limiter
(8)	OLDHAM flexible coupling
(9)	High pressure pump housing
(10)	Fuel temperature sensor (Fuel temperature in the transfer pressure chamber)
(11)	Low pressure actuator (IMV)

N.B. : The unused fuel passes via the venturi then returns to the fuel tank.

Role
Role of the high pressure fuel pump:

• The pumping of the fuel (integral transfer pump)
• To supply high pressure fuel
• To supply the diesel injectors through the high pressure common injection rail

Description
The fuel high pressure pump uses the concept of the cam and radial pistons, used also on DPC and EPIC pumps.
The cam rotates on the hydraulic head : The high pressure is generated in the fixed part of the fuel high pressure pump.

Transfer pump (pre-supply)
Role of the transfer pump:

• To pump fuel into the fuel tank
• To supply the fuel high pressure pump (compresses the fuel upstream of the low pressure actuator)
• To permit lubrication and cooling of the high pressure fuel pump with a minimum flow of 50 litres/hour

The transfer pump is incorporated in the high pressure fuel pump housing.
The transfer pump is a volumetric pump with 4 vanes. The transfer pressure is regulated at approximately 6 bars, 7 maximum.

The transfer pump consists of the following elements:

• A rotor driven in rotation by the shaft of the high pressure pump. The connection is by means of splines
• An offset stator, fixed on the high pressure pump housing. The positioning is guaranteed by 2 offset pins
• A plate with an induction hole and a delivery hole
• 4 vanes spread at 90°

A regulation valve maintains the transfer pressure at a constant value (6 bars) throughout the engine operating range by returning a proportion of the fuel to the transfer pump inlet.

Data

Engine speed (rpm)	Fuel pressure in the fuel high pressure common injection rail ( bar)	Flow injected (Kg/hr)
120	300	1,4
750	230	11
2000	1400	26,9
4000	1650	52,2

Regulation pressure	6 bars
Filling volume when empty	100 cc
Transfer pump flow rate	5,6 cm3/tr
Induction capacity	65 millibars at 100 rpm
Operation on the return circuit	Back pressure of 250 millibars maximum with 90 l/hr and the fuel at a temperature other than 40 °C
Maximum return flow	80 l/hr for an engine speed higher than idle
Induction vacuum	400 millibars absolute up to 700 millibars absolute with filter at end of interval

Low pressure actuator (IMV)

N.B.: (IMV: Intel Metering Valve)

The low pressure actuator (11) is located on the hydraulic head of the high pressure pump, supplied with fuel by the transfer pump (4) via 2 radial holes.

Role
Role of the low pressure actuator (11):

• To control the pressure in the high pressure common injection rail by regulating the quantity of fuel sent to the pumping components of the high pressure fuel pump
• To supply only the quantity of fuel necessary to maintain the fuel high pressure common injection rail pressure requested by the engine management ECU in relation to the engine operating conditions (*)

N.B. : (*) Permits, among other things, lowering of the temperature of the fuel in the return circuit to the fuel tank.

Improvement in injection system performance
The high pressure pump only compresses the quantity of fuel that is necessary to maintain, within the high pressure common injection rail, a pressure sufficient for the engine operating conditions.

Reduction of the temperature in the fuel tank (in the order of 20°C)
To prevent bubbling, the amount of heat generated by the reduction in the pressure of the fuel must be limited by reducing the leak flow.
To reduce the leak flow, it is necessary to adapt the flow of the fuel high pressure pump to the requirements of the engine in all of its operating range.
The low pressure actuator is supplied with fuel by the transfer pump.
The low pressure actuator makes it possible to obtain a pressure measured by the high pressure sensor equal to the pressure requested by the engine management ECU.
The low pressure actuator is controlled electrically by an opening cyclic ratio (Frequency between 0,4 and 2 kHz).

N.B.: A cylindrical filter is mounted on the supply holes of the low pressure actuator : The filter protects the low pressure actuator and all the components of the injection system that are located downstream of the low pressure actuator.

For each operating point: Flow introduced into the fuel high pressure pump = flow injected + injector leak flow + diesel injector control flow.
The engine management ECU determines the value of thecurrent to be sent to the low pressure actuator in relation to the following elements:

• The engine rotational speed
• The flow required
• The requested fuel high pressure common injection rail pressure
• The measured fuel high pressure common injection rail pressure

Coil resistance	5,5 ohms at 20°C
Supply voltage	Regulation between 8 and 16 volts
Operating temperature	Temperature between 40 and 90 °C
Fluid temperature	Temperature between 40 and 90 °C
Piloting logic	Normally open when not supplied The flow decreases when the current increases
Typical currents	0,6 < I < 1,3 A

ESSENTIAL: After switching off the engine, wait 10 minutes before carrying out any work.
ESSENTIAL: It is forbidden to supply the low pressure actuator directly under battery voltage when diagnostic tests are in progress. (In this case, the engine management ECU may send an error message to the diagnostic tool regarding the low pressure actuator activation status).

[darbuck]

Rhothgar and Marc thanks a million for all that information it will really help with my diagnosis and there is a lot to process aswell. I agree that it's a bad idea to deploy the parts canon and I know I am being a bit hasty ordering the regulator but I found a genuine one in Poland for small money so worth the punt. I did damage an exhaust temperature sensor aswell so I want to change it out and hope by doing so may help. The fuel quantity valve as Citroen call it is associated with the P1210 for this engine so trying to eliminate it aswell it's next to impossible to get to it to probe it so you are heavily reliant on live data. There are a good few videos related to it. I will say I wish it was a 110 in a sense because they are a much nicer engine to work on. I miss my one and I must update my profile to reflect she has moved on, sorry for the confusion. I will post up when I have done some more testing hopefully with good news or at least some answers.It sounds like your friend likes to challenge you I too have a friend who is that way inclined, it's a great sense of achievement when you solve a particularly difficult running condition. Thanks so much for your time on this I really appreciate it and it's definitely transferable information.

[Rhothgar]

I’d be interested to see some photos of the setup of the pump. It’s clearly a Lucas pump from what Marc says. Is this on the C5 X7 then?

I’ve not had time to fully read and digest what Marc has posted so currently do not understand how the pump actually works. Some of it must be ECU controlled I’d have thought.

[darbuck]

Yes it's on the X7, I haven't been able to get to the car this evening with work and now rain but here is a link to one on eBay it's better pictures than I would be able to get any way . It's driven by the exhaust cam and fuel flow and pressure is managed by the regulator (fuel quantity valve) which is controlled by the ECU.the only other electronic part on it is a temperature sensor. There is a pitot tube that vacuums the return fuel.This is why I think it's the regulator. I hope this gives a better idea of the pump set up. It's actually quite a simple system so there are a limited number of parts that can cause an issue thankfully.

See link below

https://www.ebay.ie/itm/185799135706?mk ... media=COPY

[darbuck]

Hopefully someone can confirm my thoughts, the two wires going to the regulator are both showing 0 volts so am I correct in assuming this is power side switched. I believe the opposite would be true of ground side switched.

[Rhothgar]

PASS!

It seems illogical to me that you would not have some kind of feed.

I’ve still not seen the wiring diagram. Post it here or a link to it.

It will be pulse width modulated so you may not necessarily see any voltage. It needs scoping IMHO.

Stand to be corrected.

But as I say without diagrams I cannot really give any more help as it’s not an engine I am familiar with.

[darbuck]

This is the Injection Diagram for Darbuck's DW10BTED4

This is the wiring diagram Marc kindly provided Roger. 1208 is the regulator

[darbuck]

I tried scoping it this evening I can't get at the connector with the pins without risking crossing the pins because it's buried in the back of the engine.I do however have a Delphi scan tool and can graph the regulator. Unfortunately the battery died so I need to wait until it charges again. Probably tomorrow night now.

[Rhothgar]

I tried scoping it this evening I can't get at the connector with the pins without risking crossing the pins because it's buried in the back of the engine.I do however have a Delphi scan tool and can graph the regulator. Unfortunately the battery died so I need to wait until it charges again. Probably tomorrow night now.

I'm going daft. I thought I'd seen it somewhere. It's on the first page!!!

This is currently beyond my knowledge. Pin 2 seems to be the earth side. I am making an assumption based the fact it is marked with an M. You would need to reference this back to the list of component codes.

The component has to be pulse width modulation. I cannot see how it could be controlled so quickly to switch on and off without being so. I'd have thought even then you would see some voltage when cranking.

[darbuck]

The joys of getting a bit older I am the same myself. Life is just too fast now. We don't have time to observe things the way we used to. I think your right I think scanner danner referred to the M as a symbol for earth in manufacturer drawings of ECUs. I will graph it tonight on the scan tool and post up hopefully.

[Rhothgar]

This is your friend:-

https://frenchcarforum.co.uk/wiki/Intro ... n_of_Codes

Section 7

I much prefer the older wiring diagrams as they are more legible for me. I have the factory manuals for my Citroens so it is really useful to be able to read them without having access to PC and zooming in. The wiring diagram for yours is simply awful. Horrible layout and tiny, nomenclature.

I don't know if they do wiring and installation diagrams for yours but it would be useful to have one as the one Marc has given you is the schematic. I work off all three because you can then see where splices are and loom runs. There are spliced connections off Pin 1 wire to your regulator. It might be useful to locate those without unravelling all your tape from around your wiring.

It maybe that yours scopes OK.

And I guess M stands for Monde.

[darbuck]

Interesting, no I don't think there is I think all that's available is a schematic hence the difficulty. I have an old version of sedre and doc backup but most of it is missing for some reason and works when it feels like it so I will try it. Citroen don't seem to provide much information on the X7. I would prefer a single line drawing if it was available easier to navigate. The relays are as far as I can make out self contained in the fuse box so if it goes wrong you have to change the whole bloody thing.

[GiveMeABreak]

This is the Wiring Diagram for the Darbuck's Injection System to go with the other one I put up previously, showing the interconnections - I only put these up if requested as they are quite large, being that they are Vector graphics and will scale to any size without distortion.