Cutlass V8-350 5.7L DSL (1984)
Technical Service Bulletin # 84T216C
Date: 850117
Injection Pump Pressure Regulator - Adjustment
SUBJECT
DIESEL FUEL INJECTION PUMP PRESSURE
NUMBER: 84-T-21
REGULATORS (EXCEPT CALIFORNIA)
DATE:
Jan. 17, 1985
1984 CUTLASS CIERA, CUTLASS SUPREME,
MODELS/YEARS 88, 98 & TORONADO WITH 4.3L V-6 OR 5.7L
SECTION: 6C
V-8 DIESEL ENGINE
The 1984 4.3L and 5.7L injection pump Housing Pressure Cold Advance (HPCA) regulator and Housing Pressure Altitude Advance (HPAA) regulators
are adjustable. The housing pressure regulator on California (NB2) cars is NOT adjustable. Changes in housing pressure has an effect on timing which
affects emissions, cold starts, idle quality, white smoke and noise level.
These procedures for checking and adjusting the housing pressure regulators replace "Checking Injection Pump Housing Fuel Pressure-Engine Warm" in
the 1984 Chassis Service Manuals, Section 6C5. The following diagnosis applies to Low Altitude (NA5) and High Altitude (NA6) equipped cars only.
To find out which system a car was assembled with, refer to the Service Parts Identification Label. It will disclose the system with coding as follows:
NA5 Low Altitude, NA6 High Altitude, NB2 California.
The procedure for checking housing pressure contains the information on how to check housing pressure and also the specifications and diagnosis if
necessary.
Adjusting Housing Pressure Regulators
The HPCA pressure regulator is installed in the pump cover with a fitting that adapts it to the fuel return pipe. The HPAA pressure regulator is installed
in the "outlet" side of the HPAA solenoid, which is located in the fuel return pipe. It also has a fitting that adapts the fuel return line to it.
FIGURE 1
