Diesel Data: Automotive Repair
Home >> Buick >> 1985 >> Riviera V8-350 5.7L DSL >> Repair and Diagnosis >> Powertrain Management >> Fuel Delivery and Air Induction >> Diesel MFI Pump >> Testing and Inspection >> Fuel Injection Pump Housing Fuel Pressure Check

Fuel Injection Pump Housing Fuel Pressure Check

Fig. 7 Housing pressure checking tool adapter. 1985:





1985

1. Block drive wheels, apply parking brake and shift transmission to Park.
2. Start engine and run until normal operating temperature is reached, then stop engine.
3. Remove air cleaner cover.
4. Remove MAP sensor retainer, then position sensor aside with leads and vacuum hose connected.
5. Remove air cleaner assembly and the air crossover.
6. Remove MVS adjustment hole plug.
7. Install washers onto adapter No. J-28526, Fig. 7, then attach a suitable pressure gauge to adapter.
8. Disconnect electrical connector from HPCA solenoid and the HPAA solenoid connector from engine harness.
9. Connect suitable tachometer to engine, then start engine. Check for fuel leaks and correct if necessary.
10. Raise engine speed to 1000 RPM and check housing pressure reading.
11. If pressure reading in step 10 is below 5 psi, proceed as follows:
a. Remove pressure regulator from injection pump.
b. Apply a minimum of 30 psi air pressure to regulator, first from pump side, then from outlet side. The check ball should seat when air is applied to outlet side.
c. Replace pressure regulator if operation is not as described.
d. Reconnect electrical connector to HPCA solenoid, ensuring wire colors are properly matched.
e. Turn ignition switch to Run position and ensure solenoid plunger extends upward.
f. Turn ignition switch to Off or Lock position and ensure plunger retracts automatically or can be made to do so with a light pressure applied.
g. Replace HPCA solenoid if operation is not as described.



12. If pressure reading in step 10 is 5-9 psi, proceed as follows:
a. Stop engine, then remove line fitting from pressure regulator.
b. Insert a suitable hex head key into pressure regulator and rotate adjustment screw as necessary to obtain 10 psi pressure reading.
c. Check injection timing and adjust as necessary.
d. Check operation of pressure regulator and HPCA solenoid as described in step 11.
13. If pressure reading in step 10 is 9-11 psi, proceed as follows:
a. Reconnect HPCA and HPAA electrical connectors and recheck pressure. If pressure reading rises, proceed to step 13b. If pressure reading drops to below 6 psi or above 8 psi, proceed to step 13c. If pressure reading does not change, either the HPCA or HPAA is defective.
b. Disconnect HPAA electrical connector. If pressure reading is now 9-11 psi, the HPCA is defective. If pressure reading drops to zero, check and adjust HPAA as described in steps 15 and 16.
c. Disconnect HPAA electrical connector. If pressure drops or does not change, check and adjust HPAA as described in steps 15 and 16.
14. If pressure reading in step 10 is above 11 psi, proceed as follows:
a. Disconnect fuel return line from HPAA inlet. Install a suitable hose over pipe outlet and position opposite end of hose in a small container.
b. Start engine and observe pressure reading.
c. If pressure reading does not change, perform step 12 above.
d. If pressure reading is 9-11 psi, check for restriction in return line or HPAA and correct as necessary. If no restriction is found, proceed to step 14e.
e. Reconnect pump return line to HPAA solenoid inlet and disconnect return line from HPAA solenoid outlet. Install a suitable hose over outlet and position opposite end of hose in a small container.
f. Start engine and observe pressure. If pressure is still high, check and adjust HPAA as described in steps 15 and 16.
15. Check HPAA solenoid and pressure regulator operation as follows:
a. Remove HPAA solenoid from engine.
b. Apply a minimum of 30 psi air pressure to assembly, first from pump side, then from outlet side.
c. If air does not flow freely in both directions, replace solenoid.
d. Remove pressure regulator from solenoid. If solenoid plunger does not move freely, the solenoid must be replaced.
16. To adjust HPAA solenoid, proceed as follows:
a. Install HPAA solenoid assembly.
b. Disconnect electrical connector from MAP sensor.
c. Start engine and note housing pressure, which should now read 6-8 psi.
d. If pressure reading is not within specifications, remove HPAA assembly from engine and the line fitting from pressure regulator. Insert a suitable hex key into regulator and turn adjustment screw as necessary to bring reading within specifications.
e. Install HPAA assembly and recheck housing pressure.



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