7.5. System of ignition - the general information and precautionary measuresOn the models considered in the present manual two types of systems of ignition are used: system of contactless ignition with the distributor and without that - system of direct ignition (DIS).
Systems of contactless ignition with the distributor
The contactless system of ignition equipped models of 1.5 l, 1.8 l of 1993 ÷ 1996 of the issue, 2.0 l of SOHC, 2.4 l of SOHC 1994 ÷ of 1998 of the issue, 3.0 l of SOHC and 3.5 l. Control of an ignition advancing in such systems is exercised by the special electronic block (ECU). On models of 1.5 l, 1.8 l, 2.4 l and 3.5 l the coil of ignition and the key transistor are built in in the distributor case, on models of 2.0 l of SOHC and 3.0 l of SOHC these elements are installed separately.
At inclusion of ignition tension of the battery moves on primary winding of the coil of ignition. At rotation of a shaft of the distributor alarm impulses from the onboard processor (PCM) are transferred on the key transistor of system of ignition that leads to periodic short circuit of the negative plug of primary winding of the coil (via the transistor) on weight. As a result of such interruptions in a secondary contour of the coil VV the tension transferred to spark plugs of the corresponding cylinders and providing timely ignition of air-fuel mix in them is induced.
System of direct ignition (DIS)
The system of ignition of this type is used on models of 1.6 l, 1.8 l of 1997 ÷ 2000 of the issue, 2.0 l of DOHC, 2.4 l of SOHC since 1999 by the issue, 2.4 l of DOHC and 3.0 l of DOHC. Control of an ignition advancing here, as before, is exercised by ECU or the onboard processor (PCM).
Are a part of system the sensor of a corner of turn/provision of a bent shaft (CKP) on which signals the module of management traces the current position of pistons. Analyzing information arriving from the CKP sensor, ECU/PCM determines the current frequency of rotation of the engine and exercises control of injection and ignition of air-fuel mix in cylinders. One more component of system is the VMT sensor informing the module of management passing of each of pistons of provision of the top dead point of the step of compression. Information arriving from the VMT sensor is used by the module when determining sequence (and frequencies) injection.
At inclusion of ignition tension of the battery moves on primary winding of the coil of ignition. The signals arriving from the CKP sensor will be transformed by the module of management to the operating impulses of ignition and transferred to the key transistor. The transistor provides regular short circuit of the negative plug of primary winding of the coil on the weight as a result of which in a secondary contour of the coil tension transferred to the VV spark plugs is induced.
At service of systems of direct ignition it is necessary to observe special precautionary measures:
a) If the engine is not started, do not hold the ignition key ON which are continuously turned in situation within more than 10 seconds in a row;
b) You watch that connection of a tachometer was carried out strictly according to instructions of manufacturers, - some of the released measuring instruments can not be suitable for use on these models;
c) Do not allow grounding of contact plugs of coils of ignition on weight at all, - the slightest imprudence in this question can lead to an exit of components of system out of operation;
d) Do not disconnect the battery at the working engine;
e) You watch correctness of grounding of components.