V. Monitor Test Volvo ST

V. Monitor Test Volvo ST

In Monitor Test the Volvo ST measures a number of signals and displays these values.

Guideline values
Most values measured in the Monitor Test vary with engine temperature and the signals also affect each other. Certain values are also affected by the mechanical condition of the engine.

Normal signal variations
These values apply to a warm engine (about 5 minutes after the thermostat has opened), idling, in neutral and with the NC off unless otherwise indicated.


MFI LH 2.4




Injection time
Injection time in milliseconds (ms)
Injection time can be between 1.8-2.8 ms when the engine is not loaded and is idling. This large range is because the adaptive fuel trim compensates for high fuel pressure or small air leaks etc. When the engine is warming up this time can increase to more than 7 ms. When the engine is unloaded and running at higher engine speeds than idling, injection time need not necessarily increase. This is because the engine is more efficient at higher engine speeds.




Idle air control (IAC) valve
IAC valve displayed in %.
^ Opening angle between 30-45%.
^ At speeds above idling the valve is in stand-by mode.




Heated oxygen sensor (HO2S)
HO2S voltage in Volts (V)
The HO2S signal should normally alternate between about 0.1 V and 0.9 V. When the signal is at the lower end of the scale the mixture is lean and when it is at the upper end the mixture is rich. When the engine is idling the value should alternate between a high and low voltage if engine temperature is above 70°C.
^ Alternates between 0.1 and 0.9 V.




Coolant
ECT in degrees Celsius (°C).
^ The engine is warm at about 90°C (194°F).




Load
Load in Volts (V)
The MAF sensor signal is displayed as a voltage between #7 and GND.
^ At an intake air temperature of 20°C (68°F), engine warm and idling the load is approx. 2.3 V. When the engine is heavily loaded voltage can be above 4 V.




Battery
Battery voltage in Volts (V)
Battery voltage is measured at #35 in the MFI system.

RPM
Engine speed in revolutions per minute.
^ Normal engine speed is 780 rpm.




Idling/full load
Shows if the idling switch, full load switch is on. The Idling switch is shown even if only the DI system is connected.

Air conditioning (A/C), fan
If the car has an A/C system the monitor displays whether the A/C pressostat is on.
The electronic fan control mode is displayed for cars with an electrical fan.


DI EZ 116K




RPM and battery voltage (#6) from the DI are displayed when only the DI is connected. When both systems are connected the corresponding MFI values are displayed.
See above
Displays whether EGR control is active in cars with EGR.