Century V6-260 4.3L DSL (1984)
Housing Pressure Altitude Advance (HPAA): Technical Service Bulletins
Injector Pump - Housing Pressure Altitude Advance
Bulletin 84-6C-14
Date
Aug. '84
Ref. No. 84-298-6C
SUBJECT:
HOUSING PRESSURE ALTITUDE ADVANCE
MODELS AFFECTED: 1984 4.3L V-6 & 5.7L V-8 DIESEL ENGINE
All 1984 model diesel engines except those sold in California contain a housing pressure altitude advance (HPAA) located in the fuel return line. Its
purpose is to change the housing pressure as idle car changes altitude.
The HPAA solenoid has an arrow stamped on the case and it is labeled "This end towards pump." This means put that end towards the injection pump.
If the printing is no longer legible, refer to the service manual for proper orientation. Care must be exercised during service to make sure that the HPAA
does not get reversed. If this were to happen, a Federal car will drive normally until it is driven to a high altitude. When the switch closes, the vehicle
may experience a driveability condition and it will not restart. An altitude car will drive normally at higher altitudes but may experience a driveability
condition when driven to a lower altitude.
