Hello Paul, two days ago, my VW Golf 4 developed a starting problem. Initially it would stall suddenly as I drove and would not start at all until after a while. A week later, it refused to start completely. A mechanic has tried to change the spark plugs, ignition coils and fuel pump but the car will not start. What do you suggest we do? Timothy
Hello Timothy, you might have a faulty crank shaft position sensor (CKP). This is an electronic component designed with most post 1990 petrol and diesel engines which rely on engine management systems. The CKP sensor monitors the rotational speed of the crankshaft and relays this information to the engine computer to help determine fuel injection and ignition timing.
When it fails, your car will stall suddenly or fail to start. A bad CKP sensor can be misunderstood to be a drop in fuel pressure due to a faulty fuel pump or failure of the ignition system. As in your experience, an attempt to replace the fuel system pump and ignition system components has not solved the problem.
The CKP sensor uses magnetic Hall Effect to read the revolving crankshaft. Overtime, an aged CKP sensor loses its magnetism and ability to read the crankshaft rotations. A computer diagnosis will quickly confirm whether it is the CKP sensor or something else.