How to identify the true reason why the engine refused to start? You need to first diagnose if the crankshaft is spinning? It is possible that the problem lies in the starter.
The morning did not bode well. As always, you get into your car, turn the ignition key, and in response there is silence, only a barely audible tapping of the relay. A situation familiar to every person who has encountered the problem of battery discharge in winter. This is the most harmless thing that can happen. You just need to remove the battery and charge it to start the engine. And if possible, it is best to "light" from another car. And if the box is not automatic, then you can push from the tug.
General malfunctions
So, the diagnosis is clear and extremely simple, the car will not start. But it is quite difficult to identify the reason for this behavior. To be a little more specific, let's first consider the general points for all cars, which do not depend on the type of injection or on the engine management system.
Does the starter turn, but the movement is not transmitted to the crankshaft? Note that the starter will have high revs as it rotates without load. Therefore, having good sound insulation, you may not even hear it. The reason here lies in the solenoid relay. Either it burned out, or power is not supplied to it. Test the relay first by connecting power to it. If it does not click, then it has burnt out and must be replaced.
It is much worse if a metallic grinding sound is heard as the starter rotates. This suggests that there is a breakdown of either the bendix or the flywheel crown. That is, it is necessary to remove the starter and visually assess the condition of the gear and crown on the flywheel. Also try turning the gear. Due to the overrunning clutch, it should rotate freely in one direction, but not in the opposite direction.
Malfunctions on different ignition and injection systems
If you have an injection system, then immediately pay attention to whether the electric petrol pump turns on. If you do not hear a characteristic buzz, then the fault is clearly in it, or in the wiring. Start diagnostics with the fuse. It is quite possible that it was he who failed.
In the case of a contact ignition system, look at the distributor. It contains a contact group, which has the harmful property of changing the gap, getting dirty. Until the moment of failure, the engine will "triple", work unstable. Replacing the contact group or adjusting the gap will save you from the problem.
On the contact system, the absence of a spark can be caused either by a wire break or by a breakdown of the switch. Sometimes, of course, contamination of the power supply pads of the ignition system becomes the reason for the failure to start the engine. When identifying the cause, do not forget about security systems. Broken immobilizer key may cause engine blocking. The malfunction usually lies on the surface. Therefore, first conduct an inspection of the security systems.
