DIESEL EQUIPMENT
Injection/air conditioning programming
13
CONNECTION BETWEEN AIR CONDITIONING ASSEMBLY AND INJECTION COMPUTER
The electrical connection :
- from the air conditioning computer to the diesel injection computer consists of one wire. This track only
carries the information that the AC is operating. From this, the diesel injection computer deduces the AC
selection information : track 11,
- from the diesel injection computer to the air conditioning computer consists of one wire. This track
carries all information regarding authorising and preventing operation of the compressor : track 19.
COMPRESSOR OPERATION PROGRAMMING
During certain stages of operation, the diesel injection computer stops the compressor from functioning.
Engine start programming
After the engine has started running, the compressor is prevented from functioning for 3 seconds.
Performance return programming
If the full load position is detected, the AC compressor is prevented from functioning for 8 seconds.
Stalling prevention programming
If the engine speed is lower than 650 rpm., the compressor is automatically cut off. It will only be allowed to
function again if the engine speed exceeds 775 rpm.
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STARTING - CHARGING
Starter motor
16
OPTIMA 5800 Diagnostic station
CHECKING THE STARTER MOTOR USING THE DIAGNOSTIC STATION
Checking of the starter motor is carried out using the OPTIMA 5800, by measuring the battery voltage and
the current absorbed in the engine starting phase. The following operation faults may be highlighted :
- a fault in the battery ( the voltage falls during the starting phase),
- locking of the starter motor (the current absorbed is too high),
- a fault in the engine starter gear (the current absorbed is too low).
In order to carry out the measurement, it is necessary to stop the vehicle from starting :
- for D7F and E7J engines : disconnect the engine speed sensor (located on the clutch housing ,
- for
F8Q engines : disconnect the pump electrical solenoid and isolate the terminal.
NOTE :
- an open circuit on the engine speed sensor or the ignition creates a fault memorised by the injection
computer, this fault must then be erased from the memory using the
XR25 (see "Injection" section),
- if the engine is fitted with an immobiliser, it is sufficient to lock the doors using the remote control.
FAULT FINDING
SPECIAL TOOLING REQUIRED
16-8
INJECTION
Injection fault warning light
17
PRINCIPLE FOR ILLUMINATION OF INJECTION FAULT WARNING LIGHT ON INSTRUMENT PANEL
• Vehicles not equipped with the immobiliser function:
When the ignition is switched on, the warning light illuminates constantly for 3 seconds , then extin-
guishes.
• Vehicles with immobiliser function deactivated:
When the ignition is switched on, the injection warning light illuminates constantly for 3 seconds and
then extinguishes.
When the doors are unlocked, the red immobiliser light, which was previously flashing, extin-
guishes.When ignition is switched on, it illuminates for 3 seconds , then extinguishes.
• Vehicles with immobiliser function activated:
When the ignition is switched on, the computer does not recognise the code, and stops the engine from
starting. The injection warning light remains illuminated for 3 seconds and then extinguishes.
Before the ignition is switched on, the red immobiliser light flashes. On switching the ignition on, it
flashes more rapidly.
If a fault is detected in the immobiliser system whilst the engine is running, the injection warning light
flashes in the engine speed range between idle speed and 1 500 rpm approximately .
• Fault in a component of the injection system
The warning light is illuminated if a fault has been detected in:
- the pressure sensor,
- the vehicle speed,
- the throttle potentiometer,
- the idle speed regulation stepping motor.
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INJECTION
Injection/air conditioning programming
17
THIS VEHICLE IS FITTED WITH A VARIABLE OUTPUT COMPRESSOR
AIR CONDITIONING/INJECTION COMPUTER CONNECTION
The electrical connection :
- between the air conditioning computer and the injection computer consists of a single wire (track 5).
This track carries two types of information :
-the fast idle speed request information . For this information to be transmitted to the injection
computer , two conditions must be fulfilled :
• the air conditioning function must have been selected on the control panel ,
• the pressure in the air conditioning circuit must be greater than a certain threshold.
If this information is transmitted, the fast idle speed is obtained (it is therefore normal that
sometimes, when the air conditioning is switched on, engine idling, there is no fast idle speed ).
-the Absorbed Power information. This information has no influence on the idle speed. It simply
informs the injection computer of the torque value taken up by the compressor; the computer, in
turn, acts on the idle speed regulation solenoid. The absorbed power may be visualised using the
XR25. When the air conditioning is switched on , #44 should be between 300 and 5 000 watts.
IMPORTANT: the value at #44 or idle speed is never equal to 0, whatever the status of the
compressor, off or on . The minimum value which may be read using #44 is approximately 300
watts.
- between the the injection computer and the air conditioning computer consists of a single wire (track
51). This track carries the information regarding the authorisation or prevention of compressor
operation.
COMPRESSOR OPERATION PROGRAMMING
During certain operating phases, the injection computer prevents the compressor from operating.
Programming when starting engine
The compressor is prevented from functioning for 10 seconds after starting the engine .
Recovery of performance ( D7F engine)
Depending on the torque required by the driver and on the power absorbed by the air conditioning
compressor, the injection computer stops or allows the operation of the compressor .
Anti-stalling function (D7F engine)
If the no load position is recognised , and the engine speed is lower than 600 rpm, and if the power absorbed
by the compressor is greater than 300 watts, the compressor disengages .
It engages again if:
- the no load position is recognised when the engine speed reaches 850 rpm.,
- if the no load position is not recognised when the engine speed reaches 1 800 rpm.
Thermal protection programming ( E7J engine )
The compressor does not engage in cases where the coolant temperature is greater than or equal to +
115°C.
Over-revving protection (E7J engine )
The compressor is prevented from operating if the engine speed is greater than 5 900 rpm.
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INJECTION
Adaptive idle speed correction
17
PRINCIPLE
Under normal warm engine operating conditions , the R.C.O. idle speed value at #12 varies between a
high value and a low value, until the nominal idle speed is obtained .
It is possible that during variations in the operation of the vehicle (running in, engine wear..), that the
R.C.O. idle speed value could become close to the highest or lowest values.
The adaptive correction (#21) of the
R.C.O. idle speed (#12) allows the slow variations in the engine air re-
quirement to be corrected, so that the
R.C.O. (#12) is recentred to an average nominal value.
This correction only becomes effective if the coolant temperature is higher than 75°C, 20 seconds after
starting the engine and if the nominal idle speed regulation phase has been reached.
VALUES FOR THE R.C.O. IDLE SPEED AND ITS ADAPTIVE CORRECTION
D7F 710
engineE7J 780
engine
Nominal idle speed (#06) X = 740 rpm X = 750 rpm
R.C.O. idle speed (#12) 4 %≤X≤14 % 2 %≤X≤15 %
Adaptive idle speed (#21)Limit value:
- minimum : - 4.3 %
- maximum :+3.9 %Limit value:
- minimum : - 2.4 %
- maximum :+6.2 %
INTERPRETATION OF THE GATE VALUES
In the case of excess air (air leak or throttle stop incorrectly adjusted ..) the idle speed increases, and the
R.C.O.idle speed value at #12 decreases , in order to return to the nominal idle speed; the value of the
R.C.O.idle speed adaptive correction at #21 decreases to re-centre the R.C.O. idle speed at #12.
In the case of a lack of air (contamination, etc.), the process is inverted : the
R.C.O. idle speed at #12 in-
creases and the adaptive correction at #21 also increases, in order to re-centre the #12 to an average nomi-
nal value.
IMPORTANT : It is vital, after erasing the memory from the computer (disconnecting the battery), to let the
engine run at idle speed before returning the vehicle to the customer, so that the adaptive correction can be
correctly reset.
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