Full Size Chevrolet V8-350 5.7L DSL (1984)
Housing Pressure Altitude Advance (HPAA): Technical Service Bulletins
Housing Pressure Altitude Advance - Operation
Number:
84-187
Section:
6E (VIt)
Date:
Sept., 1984
Subject:
HOUSING PRESSURE ALTITUDE ADVANCE
Model and Year: ALL 1984 VEHICLES WITH 4.3L AND 5.7L DIESEL ENGINES
TO:
ALL CHEVROLET DEALERS
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 the 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 engine may stop running and it will not restart. An altitude car will drive
normally at higher altitudes but may stop running when driven to a lower altitude.