Pauls HDI Xantia Exclusive.

[RichardW]

Restricted flow on the low pressure side could certainly cause an issue with high side pressure... If you've got a spare filter unit it would certainly be worth sticking it on! I wondered wtf all those pipes were doing - was pleased to find on my Sister's Xsara, which is Siemens, there were just the two pipes on the top,and the filter was bolted on, took seconds to get it out, compared to fighting with the Bosch one on the Xantia when I fitted a new unit a while back. Suppose I should change the filter, it must have been on 40k miles now.... Interestingly, the stored fault on mine which related to the LP pump failing (which I only cleared yesterday) was the same as you are getting, and the reg OCR was 97%..... Could you be onto something????

[taffy]

it could be slightly blocked?

[citroenxm]

10 - Engine coolant temperature sensor (1220)(1220)
10.1 - Role.
The engine coolant temperature sensor informs the ECU about the engine coolant temperature.
Role of the injection ECU according to the data received :
To adjust the preheating time.
To adjust the postheating time.
To adjust the starting flow.
To adjust the idle speed.
To authorise exhaust gas recycling (EGR).
To adjust the fuel flow.
To limit the flow injected if the temperature of the coolant is critical (anti-boil function).
To operate the fans.
To operate the logometer on the control panel (*).
To operate the warning and prewarning lights (*).

NOTE : (*) according to model.
10.2 - Description.
There are 2 assembly possibilities :
3-way blue sensor.
2-way green sensor.
10.2.1 - 3-way blue sensor.
The sensor consists of 2 NTC (negative temperature coefficient resistor).
Allocation of the connector channels :
Channel 1-Channel 2:NTC for the injection ECU.
Channel 3-Earth:NTC for the gauge on the control panel.
Electrical specifications :
Channel 1-Channel 2:Resistance at 20 °C=6200 ohms.
Channel 3-Earth:Resistance at 30 °C=1925 ohms.
10.2.2 - 2-way green sensor.
The sensor consists of a Negative Temperature Coefficient (NTC) resistor.
The higher the temperature, the greater its resistance.
Electrical specifications:resistance at 20 °C =6200 ohms.


13 - Fuel high pressure sensor (1321)(1321)

13.1 - Role.

The sensor measures the value of the high pressure in the fuel high pressure common injection rail.
Role of the injection ECU according to the data received :
To work out the amount of fuel to inject=Injection time.
To regulate the fuel high pressure in the fuel high pressure common injection rail.

The sensor is of the piezoelectrical type.
The sensor consists of stress gauges.
The sensor provides a voltage which is proportional to the fuel pressure in the high pressure common injection rail.
13.2.1 - Electrical features.
Allocation of the connector channels :
Channel 1:Earth.
Channel 2:Pressure information (0 to 5 volts).
Channel 3:+5 volts supply.
Voltage provided for a pressure of 100 bar:ð 0,5 volt.
Voltage provided for a pressure of 300 bar:ð 1,3 volt.


17 - Feature of the diesel injector control

The diesel injectors are controlled by 2 control stages of the injection ECU :
Control stage 1:Injector group 1 - 4.
Control stage 2:Injector group 2 - 3.
The control stages of the diesel injectors are used to obtain the following voltages :
A peak voltage of 80 volts required when the diesel injectors start to lift.
A voltage of 50 volts required to keep the diesel injectors open.
The control stages incorporated into the injection ECU each have a capacitor which stores the power required to control the diesel injectors.
Between each injection, the injection ECU sends pulses on the coil of the injector which is not working.
The pulses create an induced voltage to charge the corresponding control stage (capacitor).

WARNING : The control stage cannot charge itself when a fault is present on the supply line of a diesel injector.
A safety system inside the ECU disconnects the control stages when the engine is switched off.

[taffy]

i take it youve also checked the gauze in the intank pump by disasembleing it?

[citroenxm]

I changed it Taff for the one that the High Pressure Fuel system was with... which I also KNOW for a FACT it had never been fed on nothing but Diesel...

[taffy]

thats some great info by the way paul where did u get them drawings from!!?? and i had a good one on my mates transit the other day where it was guttless!! we checked everything and then decided to drop the tank...and to our suprise we found the wrapper of a cigerette box sucked up the pick up pipe!!! took it out and it flies now!!

[citroenxm]

Took me bloody ages to draw them... Good arent they?!


Added info about the Third Piston Deactivator too the Above posting....

[taffy]

lmao u got a steady hand lol!! VERY informative!!:)

[RichardW]

Paul - slightly different figures to mine, but not miles off. On a half warm engine (40C coolant) unloaded mine is showing 19% at idle, rising to 23% at 1500 rpm, and then much more slowly to 25% at 3000rpm. Which implies mine is having to run the reg more open than yours to get the required pressure off load....???? Intriguing

[citroenxm]

Did you see the Fuel System info I put on above?? Hopeing that might explain a bit more.

Ill try a regulator and another fuel filter housing on thursday and see what happens then..

[RichardW]

Do them one at a time Paul, so that if one does fix it, you will know which. Given that you have a fitted a known good pump and reg already, I'd go for the filter first - unlikely as that might seem!

[citroenxm]

I have done a Filter swap this afternoon, a complete unit..

Not sure if I imagined it but I could blow backwards through the old filter, but not so easilly on the one I was putting in..

Anyway, shall see what happens tomorrow, got a run out tomorrow.

[Hell Razor5543]

Fingers crossed, Paul.

[citroenxm]

Im NOT hopefull... we shall see...

[citroenxm]

The Plot, well problem, Thickens!!

Its not the filter house. Swapped that last night, still does it, strangely when WARM, and not cold.

Anyway, drove 65 miles, lovly and smoothly, went through some traffic lights, and STOPPED!. Went to start. NOTHING!

Checked the fuel pump, nothing wrong, but wouldn;t start.

Got car towed round to my mates house, I was litterally round the corner. So had a look this afternoon and swapped the Regulator, assuming it was at fault, initially, the car started straight away. Yaaay I thought. Put it all back together. Then tried again. NOTHING! Just turned over! So, with an aid, I held the key for about 20 seconds, and my mate wiggled some wires.. wham, into life!

So, again, left it, went in for about half an hour, and then came out to go home. NO Nothing again Just turned over...

So, this time my mate held the key and I messed with the harness... and urrrrmmm. How can I put it, it was like "The fuel pressure built up slowly enough that the engine started to fire a bit at a time untill it was running.

Once running, idled perfectly, revved perfectly, and drove ALL the way home 65 miles perfectly, THOUGH I did only drive carefully.

SO, what do we think now? ECU, Harness? I think Im now going to have to change the harness, and might do an ECU swap at the same time...

The Case Continues.......