Ignition system — general information

The Patrol/Maverick series vehicles described in this manual are equipped with one of two types of ignition systems. On the 4.2L model, the ignition system is installed with a conventional distributor type with a contact breaker, while on the 3.0L models, an electronic distributor is used. Both distributors are driven from the camshaft by means of a helical spur gear and are equipped with vacuum and centrifugal ignition advance correctors. Models 3.0 l are additionally equipped with a thermal vacuum valve (TVV) control of the work of the vacuum corrector. The valve prevents the supply of vacuum to the distributor corrector until the engine warms up to the set temperature.

In the distributor from 4.2L models, a mechanical contact breaker is used to interrupt the power supply to the primary circuit of the ignition coil. In the electronic distributor, instead of the breaker contacts, a control pulse sensor is used, and the primary current of the ignition coil is controlled by the switch. When the power supply is interrupted, a high-voltage voltage is induced in the secondary winding of the coil, which is supplied to the spark plugs through the BB wires through the distributor slider. On 4.2L models, a ballast resistor is used to further increase the ignition voltage during engine start.

Both types of distributors are equipped with an engine speed limiting device, consisting of a slider and a special screen located under the slider. The slider is equipped with a spring-loaded sliding electrode and a switching electrode. When the engine speed reaches 5000÷5400 per minute, the centrifugal force pushes the sliding electrode outward, bringing it into contact with the switching electrode. The ignition current of cylinders 1, 3, 4 and 6 is directed through the switching electrode and shield plate to the BB terminals of cylinders 2 and 5, which leads to a decrease in engine speed.