Because of the high pressure that is created when injecting fuel directly into the fuel pump, there is an increase in the chances that a leakage can occur. These leaks will interfere with the functionality of the engine due to carbon build up.

Using oil types that are different from the recommendations of the manufacturer may also trigger the high pressure fuel pump to fail. This is because the quality of oil may affect the rate of wear in the fuel pump.

Failing to change the oil in your BMW will also increase the friction between the camshaft and the lobes. When the oil levels are too low, then the friction increases. This will in turn increase the rate of wear and tear and further cause the pump to produce less pressure.

A solenoid is used to control the volume in a high pressure fuel pump. It does this by changing the port location in the pump. When this fails to happen the pressure in the fuel pump is lowered, causing failure in the pump.

One of the most common signs of a blend door problem is when the defrost is turned on, but it takes a while to get going. Most of the time, the windshield won’t defrost, does so slowly, or remains foggy after a while.

Another common sign is when the defrost or air is turned on and it pours out, regardless of how high you have the dial turned. A grinding or clicking noise often accompanies this, as the parts of the blend door scrape against one another. The noise–which can sound like someone knocking on your door–often begins or is the most noticeable right when you turn the heating/cooling system on.