HDi Tech Info & Faultfinding List...

[FlySpeck]

After my recent weeks of studying the HDi system to fix a fault in my own car, I picked up some very useful info on the way. (In particular a detailed peugeot engineering manual for the HDi engine)

A lot of it looks techie, but if you look under the section you need for say, a non start fault, I have listed for instance (cut & pasted) the conditions under which the system will cut the engine and what faults will not, in simple list form, along with sensor values for measurement and testing. Hopefully you guys feel its good enough for the mods to sticky, and we can all use it as a reference.

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8.1 - Pre-injection.

The start of preinjection is triggered before the main injection.

The injection ECU decides on a preinjection if the engine speed is less than 3200 rpm (reduction in operating noise).

Preinjection is discontinued in the following cases :
Engine speed greater than 3200 rpm.
High pressure insufficient.
Degassing the high pressure common injection rail (starting phase).
When the fuel flow is less than a minimum level.

NOTE : The pre-injection time is limited as a function of the high pressure available in the high pressure common injection rail.

The pump operates on 3 pistons :
At idle speed.
From 2/3 of full load up to full load.
The pump operates on 2 pistons :
Outside idle speed.
Below 2/3 of engine full load.

NOTE : If the fuel temperature exceeds 106 °C, the high pressure fuel pump only operates on 2 pistons (3rd piston deactivator energised).

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9 - Boost pressure regulation

The boost pressure is calculated from the following parameters :
Engine speed.
Amount of fuel to inject.

The limits of the turbocharging valve vary and depend on the load conditions.

The maximum turbocharging value is 950 mbar between 2500 and 3500 rpm.

The boost pressure can be regulated or controlled in an open loop.

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11 - Starting the engine

11.1 - General.

The starting phase is entered as soon as the injection ECU is energised.

When starting, the injection ECU controls the following elements :
Booster pump (low pressure) (cuts out after 3 seconds, if the starter motor does not crank).
Preheater plugs (if necessary).
Fuel high pressure regulator (rise in pressure).

As soon as the starter motor is operated, the injection ECU sets the value of fuel high pressure from the coolant temperature.

At the beginning of starting, the high pressure regulator is controlled by the OCR worked out by the starting cartographic map.

In this operating phase, the high pressure fuel sensor is ignored.

The fuel high pressure is regulated by one of the parameters below :
Engine speed greater than 20 rpm with at least 4 revolutions completed.
Pressure in the high pressure fuel common injection rail greater than 150 bar.

The starting phase is finished when the engine speed exceeds a value.


NOTE : The injection ECU only operates the injectors when the pressure exceeds 120 bar.

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18.1 - Displaying faults.

The appearance of certain faults in the injection system leads to the engine management lamp illuminating.

The engine management lamp illuminates if there is a fault on the following items or information :
Voltage of capacitor N°1 (diesel injector control stage in the injection ECU).
Voltage of capacitor N°2 (diesel injector control stage in the injection ECU).
Fuel high pressure sensor.
Pressure monitoring loop in the common injection rail.
Accelerator pedal sensor (stage N° 1).
Accelerator pedal sensor (stage N° 2).
Boost pressure sensor.
Air flowmeter.
Supply sensor N°1.
Supply sensor N°2.
Exhaust gas recycling function (regulation).
Boost pressure regulation electrovalve.
Fuel high pressure regulator.
Diesel injector fault (1 to 4).

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18.4 - Engine stops (stall).

The systems causes the engine to stop immediately when a fault is present on one of the following components :
Eprom in the injection ECU.
Motor speed sensor.
Camshaft position sensor.
Voltage of capacitor N°1 (diesel injector control stage in the injection ECU).
Voltage of capacitor N°2 (diesel injector control stage in the injection ECU).
Pressure monitoring loop in the common injection rail.
Diesel injector fault (1 to 4).

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18.2.1 - Reduced fuel flow.

This back-up operating mode limits fuel flow, and the engine speed cannot under any circumstances exceed 3200 rpm.

The injection system switches to "reduced flow" mode when a fault is present on one of the following components :
Fuel high pressure sensor.
Pressure monitoring loop in the common injection rail.
Accelerator pedal sensor (stage N° 1).
Accelerator pedal sensor (stage N° 2).
Inlet manifold pressure sensor.
Air flowmeter.
Vehicle speed sensor.
Exhaust gas recycling function (regulation).
Recycling regulation electrovalve (EGR).
Fuel high pressure regulator.

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17 - Engine immobiliser function

The injection ECU prevents the engine from starting by preventing injection.

Operating principle of the device:refer to the relevant documentation.

17.1 - Unlocking the system.

Every time the ignition is switched on, the authenticity of the keys is checked by one of the following systems (according to model) :
Body computer (CPH).
Transponder module.

17.2 - Locked with ignition off.

The injection ECU is automatically locked in the following cases :
After the ignition has been switched off, 10 seconds after the driver's door is opened.
A maximum of 10 minutes after the ignition is switched off.
Operation stages :
The engine immobiliser system wakes up the injection ECU via channel 66 of the connector.
Wake-up signal detected by the injection ECU.
The injection ECU controls the supply to the first stage of the double injection relay.
The injection ECU can talk with the CPH.
The CPH sends the locking order.
The injection ECU locks itself and cuts the supply to the double relay (1st stage).

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19.5 - Engine coolant temperature warning lamp.

The coolant temperature warning lamp can be controlled by one of the following components :
Injection ECU.
Water temperature sensor (3-way).
Normal operation of the warning lamp :
The warning lamp illuminates if the temperature exceeds 118°C.
The warning lamp goes out if the temperature falls below 117°C.
The warning lamp flashes if there is a break in the wiring of the coolant temperature sensor.

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The booster pump, submerged in the tank, comprises the following components :
(18) Direct current motor.
(19) Roller pump.
(20) Rotor.
(21) Safety valve.

NOTE : Rating of the safety valve:ð 7 bar.
The booster pump is supplied with 12 volts through the double injection relay in the following cases :
As soon as the engine is switched on, for 2 to 3 seconds.
Engine running.

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2 - Deactivator of the 3rd piston of the high pressure fuel pump (1208-6)(1208-6)

2.1 - Role.

Role of the deactivator of the 3rd piston of the high pressure fuel pump :
To reduce the power absorbed by the high pressure pump if the vehicle is used at low load.
To limit the high pressure quickly in the event of a problem.

2.3 - Electrical features.

Control:injection ECU.

Type:"all or nothing" control through earth.

When the 3rd piston deactivator is energised:the pump operates on 2 pistons.

When the 3rd piston deactivator is not energised:the pump operates on 3 pistons.


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5 - Battery (BB00)BB00

The charge level of the battery is important for the HDI direct injection system to operate.


WARNING : A battery voltage of less than 10 volts disturbs the operation of the HDI direct injection system.
The ECU memorises a fault in the following cases :
Battery voltage greater than 17,5 volts.
Battery voltage less than 7 volts.

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6 - Double injection relay (1304)1304

The double injection relay is controlled directly by the injection ECU.

The first relay of the double injection relay supplies the following components :
Booster pump (low pressure).
Boost pressure regulation electrovalve.
Air flowmeter.
Recycling regulation electrovalve (EGR).
The second relay of the double injection relay supplies the following components :
Injection ECU (power part).
Control relay of the electric cooling fans.

NOTE : After switching off the ignition, the double injection relay remains energised for 4 seconds or for 6 minutes in the event of post-ventilation.
During a request to unlock the injection ECU by the engine immobiliser system (specific ECU channel) :
The ECU supplies the double injection relay.
The ECU is re-supplied by the double injection relay (power).
Dialogue between the injection ECU and the engine immobiliser system is possible.
At the end of dialogue, the injection ECU cuts the supply to the double injection relay.

WARNING : The engine immobiliser system wakes up the injection ECU via channel 66 of the connector.

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Accelerator pedal sensor (1261)(1261)

7.1 - Role.

The sensor is linked to the accelerator pedal by a cable.

The wheel sensor :
Records the driver's request (acceleration, decelaration).
Sends information to injection ECU.


Allocation of the connector channels :
Channel 1:Output signal 1.
Channel 2:Output signal 2.
Channel 3:5 volts.
Channel 4:Earth.
Accelerator pedal released :
Voltage between earth and channel 1:0,5 volt.
Voltage between earth and channel 2:0,28 volt.
Accelerator pedal pressed fully down :
Voltage between earth and channel 1:3,35 volts.
Voltage between earth and channel 2:1,6 volt.

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8 - Engine speed sensor (1313)(1313)

8.1 - Role.

The sensor is located opposite the teeth of the flywheel.

The sensor is used to work out the following parameters :
Engine rpm.

The sensor is of the inductive type.

Components of the sensor :
A permanent magnet.
An electric winding.

The sensor provides an electrical signal every time a tooth on the flywheel passes by (change in magnetic field).

The 58 teeth are used to work out the engine speed.

The 2 missing teeth are used to work out the crankshaft position (no signal).


NOTE : The air gap is not adjustable.

8.3 - Electrical features.

Allocation of the connector channels :
Channel 1:Signal.
Channel 2:Earth.

Resistance between channels 1 and 2:50 ohms.

Features of the signals emitted:variable frequency alternating voltage.


WARNING : The sensor wire is not screened, therefore always follow the correct harness route.

8.4 - Location.

Location:on the clutch housing.

9 - The camshaft position sensor (1115)1115

9.1 - Role.

Role of the injection ECU according to the data received :
To synchronise fuel injections with respect to the position of the pistons.
To recognise top dead centres.

The camshaft sensor provides a square signal for the injection ECU.

The camshaft sensor is located opposite a target driven by the camshaft pulley.

The sensor is used to synchronise fuel injections with respect to piston position (sequential injection).

The plastic lug (24) is used to adjust the air gap in the factory.


NOTE : The plastic lug is destroyed the first time the engine is started.

IMPORTANT : When refitting a camshaft sensor, it is necessary to keep the gap between the sensors and target E = 1,2 (+0 ; +0,1) mm.

9.3 - Electrical features.

Air and fuel supply:injection ECU.

Allocation of the connector channels :
Channel 1:5 volts supply.
Channel 2:Signal.
Channel 3:Earth.

The voltage slots are between 0 and 5 volts.

Signal emitted :
Presence of metal earth opposite the sensor:0 volt.
Absence of metal earth opposite the sensor:5 volts.

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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.

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[teamster1975]

Superb post, I'm copying it to the KB!