Engine Management system

At Car Servicing and You, our fully equipped workshop in Carnegie, next to Caulfield and Malvern East, provides engine management system diagnosis and repairs for all makes and models. All our car repairs come with a minimum 12 month/20000km warranty.

The check engine light which is usually located in the instrument cluster is the engine management system’s warning light and is illuminated if the ECU registers a fault has occurred in the engine management system. If a fault occurs the ECU will record the fault code and this can be downloaded to help in diagnosing faults with your vehicle.

Common Engine light on problems include:

• Oxygen sensor fault (can be caused by poor quality fuel)
• Catalytic convertor failure
• Engine misfiring
• Emissions system fault

The engine management system consists of several components that are monitored by the electronic control unit (ECU). The ECU is a computer which interprets electrical signals received from various sensors and calculates the correct fuel/air mixture to deliver to the engine so that it can respond to various driving situations.

As the engine requires various amounts of fuel to suit different operating temperatures (ie: cold engines require more fuel) the ECU needs to establish the engine temperature and does this via the coolant temperature sensor.

Ambient air temperature also plays a role and an air temperature sensor sends a signal to the ECU to help determine the need for richer or leaner fuel mixtures.

The ECU signals the fuel pump to run when the ignition key is turned to the start position and the throttle position sensor helps the ECU determine whether the engine is idling, accelerating or at full throttle and the ECU adjusts the fuel mixture to suit. Fuel is delivered under pressure to the top of the fuel injector which delivers fuel in a fine spray into the induction system. The crank angle sensor gives the ECU an indication of engine speed and piston position to help the ECU determine injection timing.

Engine management systems also incorporate the ignition system by controlling spark timing which results in optimised performance and emission levels. Most modern cars have a direct ignition system which uses an ignition coil for each cylinder. The ECU fires the coil at the correct time using references from various sensors.