Diagnostics of diesel engine faults (Mazda 121 (3))

When the engine does not start, the cause should be looked for systematically. In order for the engine to start at all, two basic conditions must be met in a gasoline engine: the fuel-air mixture must enter the cylinders and a spark must jump between the spark plug electrodes. In this regard, you must first check whether fuel is being supplied at all. What to do in this case is described in the chapters "Fuel system" and "Gasoline injection system".

To determine whether there is a spark, you need to pull the plug out of the spark plug, unscrew the plug, insert it back into the plug and press it to the "ground". In this case, the plug and high-voltage wire should be held not by hand, but with a well-insulated clamp. An assistant should crank the engine with the starter.

Caution: To prevent damage to the catalytic converter, gasoline must not be injected into the fuel system. To do this, remove the fuel pump relay.

Warning! Observe safety precautions when working with the electronic ignition system.

For a diesel engine, check the preheating system and the fuel system.

Malfunction: the engine does not start or starts poorly.