The rotational speed of the engine calculated by the MEMS ECU using the crankshaft sensor. Faults in the crankshaft sensor or associated wiring may be indicated if this display reads 0 during engine cranking.
Manifold Absolute Pressure
Shows the pressure measure by the internal MEMS air pressure sensor. This value should show atmospheric pressure of 100 KPa when the engine is stopped and a lower value between 25 – 40 KPa during engine idle conditions. Very high values may indicate problems with the sensor inside the MEMS or more likely a blocked or disconnected vacuum pipe. Moderately raised values may indicate mechanical problems with the engine.
Shows the position of the throttle disc obtained from the MEMS ECU using the throttle potentiometer. This value should change from a low value to a high value as the throttle pedal is depressed.
IAC Motor Position (Stepper Motor Position)
Shows the position of the IACV stepper motor as calculated by the ECU. The ECU has no method of actually measuring this position but instead works it out by remembering how may steps it has moved the stepper since the last time the ignition was switched off. If a stepper motor fault exists, this number will be incorrect. This value will normally be changing during idle condition as the ECU makes minor changes to the idle speed. A value of 0 during idle conditions indicates a fault condition or poor adjustment, as does a very high value.
Check the Jack Count in the ECU Protocol Values for systems using a throttle body where the idle air is controlled by a stepper motor which directly acts on the throttle disk (normally metal inlet manifold), the count indicates the number of times the ECU has had to re-learn the relationship between the stepper position and the throttle position. If this count is high or increments each time the ignition is turned off, then there may be a problem with the stepper motor, throttle cable adjustment or the throttle pot. On systems using a plastic throttle body/manifold, the count is a warning that the MEMS ECU has never seen the throttle fully closed. The count is increased for each journey with no closed throttle, indicating a throttle adjustment problem.
This shows the voltage of the vehicle supply measured internally by the ECU. Large errors in this measurement will lead to possible poor starting and errors in idle CO.
This shows the coolant temperature as measured by the ECU. If the sensor is open circuit, a default value of about 60C will be displayed. During engine warm up, the value should rise smoothly from ambient to approximately 90C. Sensor faults may cause several symptoms including poor starting, fast idle speed, poor fuel consumption and cooling fans running continuously.
Air Intake Temperature
This shows the temperature measured by the ECU using the inlet air temperature sensor. If the sensor is open circuit, then a fixed default value will be displayed. The inlet air temperature is used by the ECU to retard the ignition timing to avoid knock and trim the fuelling when hot. If the sensor is not operating correctly the engine performance may be impaired slightly.
This shows the voltage across the oxygen sensor as read by the MEMS ECU. Once the engine is fully warm, during most idle and driving conditions, this voltage will switch rapidly between a value between 0.0v-0.2v to a value between 0.7v and 1.0v. The sensor detects the presence or absence of oxygen in the exhaust gas. When the exhaust gas has oxygen present the ECU will read a low voltage.
Display of the current fuelling correction. This is shown as a percentage of the mapped (open loop) value. This percentage is continuously updated by the MEMS ECU whenever the conditions for closed loop fuelling are present. At other times, the feedback value will show a value of 0%, indicating that closed loop fuelling is not operational. High values e.g. +20% indicate that feedback is attempting to compensate for fuelling being too lean and low values e.g. -20% for fuelling being too rich. Note: Misfire condition will be shown as high values, as feedback will be fooled into compensating for a system running too lean.
This is a facility which is built into the MEMS ECU to overcome some situations during the service life of a vehicle where it might be wished to eradicate a problem such as a low octane fuel being constantly used or engine wear by slightly advancing the ignition timing. the idle speed of the engine. The function can be removed by resetting the adaptive values.