- Check for correct starting procedure
If the correct starting procedure is not used the car may not start.
By following the correct starting procedure, you will be able to verify whether or not the car has a starting problem.
- Check the fuel supply system
Once it has been verified that a problem exists, the first step is to check the fuel supply. If there is an air leak in the suction lines between the injection pump and the fuel tank, fuel may be siphoned out of the fuel line back to the tank.
A plugged fuel filter or blocked fuel line will also prevent fuel from being delivered to the injection pump.In areas where the temperature drops below 20° F (-7°C) the fuel tank strainer should be removed to prevent wax crystals from blocking the fuel supply. This is only necessary on the Rabbit, Jetta, Pick-up, and Dasher. Other 4 cylinder diesels do not have a fuel tank strainer.
After you have checked to make sure that fuel is being delivered to the injection pump, the next step is to see if fuel is being delivered to the injectors. This is done by loosening one of the union nuts on an injector line while cranking the engine.
Poor fuel quality can cause a cold running problem or a no start condition. The fuel must be properly winterized and any additives that are used must be used according to the manufacturers instructions.
- Check the glow plug system
During cold starts, the compression heat is dissipated by the cold engine. If the glow plugs are not operating properly, not enough heat will be produced during cranking to start the engine. The test procedure is in two parts, the first step is to check the relay and wiring. The second step is to check the glow plugs.