"REMINDER: 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 SOUND. IT IS A RESULT OF THE POSITIONING OF THE PLUNGER STOPPER INSIDE THE HIGH PRESSURE PUMP. SOME MAY HAVE A PLUNGER STOPPER POSITION THAT WHEN COMBINED WITH CERTAIN FUEL TEMPERATURES OR FUEL FORMULATIONS, MAY RESULT IN AERATION OF THE FUEL WITHIN THE BODY OF THE PUMP CAUSING THIS SOUND WHEN THE ENGINE IS IDLING. THIS RESULT IS NON-DETRIMENTAL TO THE FUEL SYSTEM OR ENGINE. NOT ALL PUMPS WILL EXHIBIT THIS CONDITION. A PRODUCTION CHANGE WAS MADE TO CONSISTENTLY ORIENT THE POSITION OF THE PLUNGER STOPPER DURING ASSEMBLY THUS ELIMINATING THE SOURCE OF THE SOUND. ONCE THE CHIRPING SOUND HAS BEEN CONFIRMED, THE HIGH-PRESSURE PUMP ASSEMBLY MUST BE REPLACED TO REMEDY THE CONDITION."
