Direct ignition systems include camshaft and crankshaft position sensors (SMR and TFR), a set of ignition coils individual for each of the cylinders and an ignition module. Onboard processor (ECM) generates reference signals that determine the order of connecting the ignition module to each of the coils in accordance with the current position of the crankshaft. The ignition timing is set by the control module based on the analysis of signals from various information sensors that are part of the ignition and fuel injection systems. This includes ECT, VSS, TPS, AT position sensors, air flow meter/MAF sensor, knock sensor (see chapter Engine management and emission control systems). The ignition module distributes the signal between the coils and controls the duration of the pulses of their operation (by primary current).
Special precautions should be observed when servicing direct ignition systems:
- a. If the engine does not start, do not keep the ignition key continuously turned to the ON position for more than 10 consecutive seconds;
- b. Make sure that the connection of the tachometer is carried out strictly in accordance with the instructions of the manufacturers, some of the meters produced may not be suitable for use on these models;
- c. In no case do not ground the contact terminals of the ignition coils to ground - the slightest negligence in this matter can lead to failure of the ignition module and / or the coil itself;
- d. Do not disconnect the battery while the engine is running;
- e. Make sure the ignition module is properly grounded.