Attention. Since the vehicles covered in this book use a high energy ignition system, do not disconnect the high voltage wires and test the ignition circuits for a spark while the engine is running, as this may result in personal injury, as well as burnout of high voltage insulation and failure of the system. ignition.
It is not allowed to disconnect the wires from the battery terminals while the engine is running, as this may damage the switch.
After servicing or repairing the vehicle, before starting the engine, make sure that the high voltage wires are connected securely to the coil and spark plugs.
Proximity sensor
The performance of the non-contact sensor located in the sparking moment sensor can be checked with an indicator assembled according to the diagram shown in fig. 152. The indicator uses resistors of the MLT type, 1 W; capacitor C1 - type KLS1, and C2 - type K53-14. As an indicator lamp HL1, a car lamp A12, 3 W was taken.
Instead of a KT816B transistor, you can use a KT814B type transistor. The indicator wires are soldered to a three-terminal block Ш1 of the same type that is connected to the spark moment sensor on the car.
To check the non-contact sensor, connect the indicator to the spark moment sensor instead of the ignition system wiring harness and turn the engine with a starter and a special key for the bolt on the crankshaft. If the HL1 lamp flashes during rotation of the crankshaft, then the proximity sensor is working.
The serviceability of the proximity sensor can also be checked using a voltmeter according to the diagram shown on rice. 154. The verification procedure is described in the next section. This method is more accurate, as it allows you to check the magnitude of the voltage pulses generated by the sensor using a voltmeter.
Switch
The functionality of the switch can also be checked with a 3W A12 lamp. To check, it is necessary to disconnect the brown wire coming from the terminal from the ignition coil «1» switch, and connect the tip of the wire to the test lamp. The other output of the lamp is connected to the terminal of the ignition coil and the engine is turned with a starter. If the lamp flashes during rotation of the engine crankshaft, then the switch outputs current pulses to the ignition coil.
The described method allows only a rough estimate of the operability of the switch - whether it produces current pulses or not. Pulse parameters (size and duration, shape) cannot be verified by this method. And they can seriously affect the operation of the engine, especially at high engine speeds. Therefore, the following test of the switch on the bench using an oscilloscope and a rectangular pulse generator is more accurate.
Ignition coil and high voltage wires
The performance of these elements can be checked using a high-voltage arrester. The simplest spark gap consists of two pointed metal rods, the gap between which can be adjusted. The rods are fixed on a plate of insulating material (plastic. ceramics).
To check, disconnect the high voltage wires from the spark plugs and attach them to the spark gap electrodes. Set the air gap between the electrodes of the arrester 7-10 mm. If, when the engine is rotated by the starter, uninterrupted sparking is observed between the electrodes of the arrester, then the ignition coil and high voltage wires are in good order.