Location of the plug in the ignition timing adjustment socket on 260 models in the position for operation on 95 unleaded gasoline
Location of the plug in the ignition timing adjustment socket on 300 models in the position for operation on 95 unleaded gasoline
EZL ignition system
The EZL ignition system works based on the signal received from the crank angle sensor. The ignition system sets the required ignition timing based on information about engine speed, crankshaft position and intake manifold vacuum obtained from sensors mounted on the engine.
A distinctive feature of the EZL ignition system is that it is impossible to adjust the initial ignition timing by turning the distributor housing relative to the shaft.
However, the initial ignition timing can be changed depending on the type of fuel used. To do this, you need to change the position of the switch plug in the tuning socket located in the engine compartment next to the ECU. Resistors of various resistances are installed in the switching plug. The plug can be installed in several positions according to the marks on the plug. Depending on which plug resistor is currently connected to the socket pins, the ignition ECU increases or decreases the initial ignition timing in 3°increments.
The ignition timing can also be measured using a stroboscope.
Attention! The ignition timing must be checked with the engine warmed up to normal operating temperature. It is advisable to complete the ignition timing test before the coolant temperature exceeds 95°C or before the radiator fan turns on.
1. Connect the stroboscope according to its instruction manual. In this case, the start of the stroboscope must be carried out from the high-voltage wire of the 1st cylinder.
2. Start the engine at idle speed. Aim the strobe light at the pointer on the timing chain cover. The mark on the crankshaft pulley appears to be stationary and should line up with the pointer. If the mark moves to one side or the other, then the idle speed is unstable. When checking the ignition timing, all electrical consumers must be turned off and the radiator fan must not work. When the engine is idling for some time, even when the engine is warmed up to normal operating temperature, especially at high outside temperatures, the idle speed may be unstable.
3. Determine the ignition timing from the mark on the crankshaft pulley, aligned with the pointer.
4. If the ignition timing differs by more than 3°from the required one, the plug in the tuning socket may not be installed correctly. Check the position of the plug in the adjustment socket and, if necessary, set it according to the type of fuel used.