THE PURPOSE OF THIS BULLETIN IS TO PROVIDE INFORMATION REGARDING A HIGH-PITCHED “CHIRP”, “SQUEAK” OR “CRICKET” SOUND YOU MAY HEAR COMING FROM THE ENGINE’S HIGH-PRESSURE FUEL PUMP. NOT ALL PUMPS MAY EXHIBIT THIS CONDITION. SOME MAY HAVE INTERNAL COMPONENTS WHICH IN COMBINATION WITH CERTAIN FUEL TEMPERATURES OR FUEL FORMULATIONS, MAY RESULT IN AERATION OF THE FUEL WITHIN THE BODY OF THE PUMP AND CAUSE THIS SOUND WHEN THE ENGINE IS IDLING. THIS RESULT IS NON-DETRIMENTAL TO THE FUEL SYSTEM OR ENGINE.
