A feature of the ZMZ-40524 engine ignition system is the presence of four separate ignition coils installed directly on the spark plugs, instead of two separately installed coils serving two engine cylinders each

Individual coils 40904.3705000 (ZS-K-1×1 0 221 504 027 f. “Bosch”) of transformer type are installed on the valve cover.

The electronic control unit processes data received from the system sensors and controls the ignition coils by sending low voltage pulses to them.

Removing the ignition coil

In the ZMZ-40522 engine, sparking occurs simultaneously in two cylinders: 1st and 4th or 2nd and 3rd, and in the ZMZ-40524 engine - in accordance with the order of operation of the cylinders.

The ignition system has no mechanical moving parts, so it does not require adjustments or maintenance during operation.

The ignition coils installed in the ignition system of the ZMZ-40522 engine are similar to the ignition coils of the ZMZ-4061 and ZMZ-4063 engines, therefore their testing and replacement are similar to those described for these engines.

The ignition coils of the ZMZ-40524 engine are radically different in design; their removal and installation are described in this article.

To initially check the coil, you need to remove the coil from the spark plug well and insert a known good spark plug, and press the spark plug body against ground.

The wiring also needs to be connected to the “ground” of the coil (where the coil was attached with a nut) to the ground of the engine. We start the engine for a short time.

The presence of a spark between the electrodes of the spark plug will indicate the serviceability of the coil.

To fully check the ignition coil, you need to disconnect the harness block from the ignition coil and remove the coil from the spark plug well.

Connect an ohmmeter to the terminals of the primary winding and measure its resistance, it should be 0.4 - 0.5 Ohm.

Connect an ohmmeter to the terminals of the secondary winding and measure the resistance, it should be 5 - 7 kOhm.

Removing the ignition coil

1. Disconnect the wire from the negative terminal of the battery.

Removing the ignition coil

2. Squeeze the harness block clamp

Removing the ignition coil

3. Disconnect the wiring harness block from the ignition coil

Removing the ignition coil

4. Unscrew the nut securing the coil to the cylinder head cover

Removing the ignition coil

5. Lift the coil and remove the tip from the spark plug

Removing the ignition coil

6. Removing the coil from the spark plug well

We remove the remaining ignition coils in the same way

Install the parts in reverse order.