If your Volkswagen Golf Mk4 is turning over but not starting, and there's no fuel getting to or past the fuel filter, there are several potential issues that could be causing this problem. Here are a few suggestions for troubleshooting:
Check the fuel pump relay
The fuel pump relay is responsible for sending power to the fuel pump, which pressurizes the fuel system. If the relay is faulty, the fuel pump may not be getting power. Check the relay by swapping it with a known good relay or testing it with a multimeter.
Check the fuel pump fuse
If the fuel pump fuse is blown, the fuel pump won't get power and the engine won't start. Check the fuse and replace it if necessary.
Check the fuel pump
If the fuel pump relay and fuse are both good, the next step is to check the fuel pump itself. You can do this by listening for the sound of the fuel pump when you turn the key to the "on" position. If you don't hear the pump, it may be faulty and need to be replaced.
Check the fuel lines
If the fuel pump is working but no fuel is getting past the fuel filter, there may be a clog or blockage in the fuel lines. Check the lines for any signs of damage or debris and clear any blockages that you find.
Check the fuel pressure regulator
The fuel pressure regulator is responsible for maintaining a consistent fuel pressure in the system. If the regulator is faulty, it may be causing a drop in fuel pressure, which could prevent fuel from reaching the engine. Test the regulator with a fuel pressure gauge to see if it's functioning properly.
These are just a few suggestions for troubleshooting a Golf Mk4 that won't start. If none of these solutions work, it may be necessary to take your vehicle to a mechanic for further diagnosis and repair.
