Engine - Lack of Performance
86volvo03SECTION GROUP NO.
24 117
DATE
FEBRUARY, 1986
RE: D24T ENGINE
PERFORMANCE
740/760
THIS BULLETIN APPLIES TO THE U.S. AND CANADA, AND SUPERCEDES SB 24-117, FEBRUARY 1985.
Insufficient acceleration or lack of performance of diesel engines may be caused by a missing inner O-ring in the fuel filter. Adverse performance is most noticeable during high torque conditions when maximum fuel delivery is required.
NOTE: THE INNER O-RING AND RETAINER ARE NOT INSTALLED ON NEW VEHICLES BECAUSE THE FUEL FILTER THREADS ARE COATED WITH SEALING COMPOUND AT INSTALLATION. Since this seal is broken during filter removal, the retainer and Oring included in the fuel filter kit must be installed on the new fuel filter.
The drawings below show the filter and the cause of the problem.
In drawing "A", the inner/outer O-rings are correctly placed and fuel enters the filter outer chamber and leaves up through the center of the housing.
In drawing "B", the inner O-ring is missing, which allows some fuel to continue circulating inside the filter instead of being forced out to the injection pump. This causes lack of power from an insufficient amount of fuel being delivered to the engine.