The reasons for weak engine ignition and fuel injection are as follows: Starter works, but the engine does not start: It could be an electrical or electronic fault. The occurrence is often sudden without any warning. Electrical faults include: blown fuse, open circuit in the high-voltage coil, open circuit in the low-voltage circuit, detached central ignition wire, leaking distributor rotor, or damaged spark plugs. Electronic faults mainly refer to the failure of the central computer control board. Then there are fuel system faults. Engine stalling caused by fuel system issues often comes with symptoms like weak engine power and a spongy accelerator pedal. Possible fuel system fault locations include: malfunctioning fuel pump, blocked fuel line, clogged fuel filter, failed carburetor, damaged injector, etc. Sometimes, the fuel tank may be empty without the owner realizing it. Adding a few liters of gasoline can solve all the problems. Lastly, it could also be a mechanical fault. Common mechanical faults include: broken timing belt (chain), cylinder leakage with no pressure, etc. Starter does not work or barely works: In this case, the first thing to check is the battery. There are many ways to check it, and having a voltmeter on hand is ideal. Connect the positive and negative terminals of the battery, then turn the key to ignite. If the voltage reading suddenly drops below 8 volts when the power is connected, the battery definitely has an issue. Without a voltmeter, you can use a 12-volt small bulb and a short piece of power wire instead. The method is the same—if the bulb suddenly dims significantly, it also indicates an aging battery. In many cases, the battery may already be failing but can still power the headlights. This is not unusual. Only at the moment of ignition can the battery's performance be truly tested, as this is when it bears the highest load. Another simple method is to visually inspect the battery's outer casing. If it appears swollen or deformed, it absolutely needs replacement. Apart from the battery, other reasons for the starter not working could be a damaged ignition switch, faulty ignition relay, or a defective starter itself. Additionally, check the grounding wires and fuses.
