Why Doesn’t the Engine Start? Reasons the Engine Fails to Start.

No fuel

The reason the engine won’t start may be one of the following: the fuel gauge isn’t working properly or is faulty, so you may not know whether there’s enough fuel to start the engine. For example, if the fuel gauge needle is at the very bottom, it means fuel is insufficient. Similarly, if it stays stuck at the very top, the gauge is faulty. If you can’t see any reading on the fuel gauge, add at least 1 liter if you’re driving a motorcycle, or at least 5 liters if you’re driving a car.

Water in the fuel tank

If, for any reason, water leaks into the fuel tank and therefore the fuel system, your engine may not start.
SOLUTION: Remove the fuel tank and drain its contents completely. Then fill it with fresh/clean fuel. Depending on the situation, you may also need to remove and clean the injectors or the carburetor.

Clogged fuel filter / fuel pump

Replace the fuel filter element as recommended by the manufacturer. Replace the fuel pump.
Related article: How is a fuel pump fault diagnosed

Restricted Airflow

The engine isn’t starting due to restricted airflow to the engine. This may be caused by obstructions such as dry leaves in the front grille vents or a clogged air filter.
SOLUTION: Clear the obstructions in the air intake ducts.

Clogged air filter

One reason the engine won’t start may be a clogged air filter. Remove the air filter element and clean/replace it as recommended by the manufacturer.

Pay attention to the dashboard lights. If the “check engine” light stays on, there is a problem with the engine management system. In this case, you may need to consult a qualified technician.

Fuel Injection Pump (FIP) Solenoid

If the solenoid connection that activates fuel supply to the FIP is disconnected, the diesel engine will not start.
SOLUTION: Connect the wire to the FIP solenoid and secure it firmly / Replace a blown solenoid fuse.

Clogged injectors

If your engine’s injectors are clogged, the engine will not start. Carbon deposits on the injector tips block them, causing faulty/insufficient injection.
SOLUTION: Remove and clean the injectors. Check the correct injection pressure.

The Battery Charge May Not Be Sufficient.

If your car’s/motorcycle’s battery drops below 9 volts, it may not start the engine. A battery must supply at least 10 volts to start the engine.
Related article: How do we tell the battery is dead

The Cause May Be the Spark Plugs

The spark plugs may be faulty or may not be making proper contact, so the ignitions needed to start the engine may not be occurring.
Related article: How is a spark plug replaced
Related article: Spark Plug Faults and Their Causes

The Battery Cable May Be Loose

If your car’s/motorcycle’s battery cable is loose, it may not start the engine. In this case, you may hear a clicking sound when you turn the ignition key.
SOLUTION: Tighten the battery terminals sufficiently.

Mechanical failure inside the engine

There can be many causes of mechanical failure in an engine, such as pistons seizing, valves breaking, connecting rods bending, pulleys breaking, etc.
SOLUTION: A poorly maintained engine can lead to this kind of mechanical failure. For this reason, the engine needs to be thoroughly inspected and analyzed to determine the exact nature of the cause.

Clogged muffler

One reason the engine won’t start may be a blockage in the muffler or exhaust pipe. If the muffler/exhaust pipe is clogged or there is an obstruction, the engine won’t start either.
SOLUTION: Clear the blockage in the exhaust pipe and clean it.