Hummer H1 (1992-1998). Manual - part 34

2-32. FUEL INJECTION PUMP REPAIR (Cont’d)

89. Install electrical shutoff solenoid (9) in cover (11).

90. Install fiber washer (7), washer (6), lockwasher (5), nut (4), lockwasher (12), ground strap (13) and

locknut (14) on stud (10).

91. Install fiber washer (7), washer (6), lockwasher (5), and nut (4) on stud (8).
92. Install shell (3), washer (2), and terminal (1) on stud (8).

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Change 2         2-125

2-32. FUEL INJECTION PUMP REPAIR (Cont’d)

93.

Install washer (15) between ground strap (16) and cover (11).

C

CA

AU

UT

TIIO

ON

N

When installing cover on housing, cover must be positioned on
housing ahead of threaded holes and slid rearward to align holes
in cover with threaded holes in housing. Incorrect installation of
cover may cause pump to malfunction.

94.

Install gasket (31) and cover (11) on housing (30) and secure with three screws (17), lock-
washers (18), and washers (19). Tighten screws (17) to 35-45 lb-in. (4-5 N

•

m).

95.

Install timing cover (28) and gasket (27) on housing (30) and secure with two screws (29).

96.

Using end cap wrench, tighten end cap (26) to 30-37 lb-ft (41-50 N

•

m).

97.

Install transfer pump end cap locking screw (25), plate (24), flat washer (23), and rubber washer
(22) in hydraulic head (21). Tighten screw (25) to 70-80 lb-in. (8-9 N

•

m) using 5/32-in. hex head

driver.

98.

Tighten two head locking capscrews (20) to 180-220 lb-in. (20-25 N

•

m).

99.

Remove pump (30) from holding fixture and vise.

FOLLOW-ON TASKS: • Calibrate fuel injection pump (paras. 2-33, 2-34, or 2-35).

• Install fuel injector pump (para. 2-41).

2-33. PRE-1990 (6.2L) FUEL INJECTION PUMP (DB2829-4523) CALIBRATION

This task covers:

a. Test Bench Requirements

c. Injection Pump Check (Prior to Service)

b. Injection Pump Information

d. Injection Pump Settings (Following Pump Repair)

INITIAL SETUP:

Tools

General mechanic’s tool kit

automotive (Appendix E, Item 1)

Special Tools

Roller-to-roller setting tool

(Appendix E, Item 45)

Linkage gap tool (Appendix E, Item 49)

Automatic advance indicator

(Appendix E, Item 50)

Throttle lever gauge (Appendix E, Item 51)
Protractor (Appendix E, Item 52)

Air timing gauge (Appendix E, Item 53)

Holding fixture (Appendix E, Item 46)
Torx drive (Appendix E, Item 42)

Manual References

Test Equipment

Digital tachometer

Voltage source (variable)

Pressure gauge (0-160 psi, 1 psi increments)
Pressure gauge (0-30 psi)
Vacuum gauge (0-30 in. Hg)
Flowmeter with three-way valve
Temperature gauge (0°-250°F)
Zero-backlash coupling device
Calibrating nozzles and lines
Orifice 13211
Calibration stand

Materials/Parts

Calibrating fluid (Appendix B, Item 4)
Sealing compound (Appendix B, Item 19)

NOTE

The following calibration procedure applies to pre-1990 6.2L fuel
injection pumps. Refer to para. 2-34 for calibration on 1990 6.2L
and above pumps and para. 2-35 for 6.5L pumps.

a. Test Bench Requirements

The fuel injection pump requires a test bench capable of at least 2250 rpm shaft speed. The test bench
must be equipped with the following items:

(a) A zero-backlash coupling device.
(b) A digital tachometer.
(c) A variable voltage source.
(d) Test gauges:

(1) 0-160 psi (0-1103 kPa) pressure gauge calibrated in 1 psi increments to measure transfer Pump

pressure. This gauge should be located as close as possible to the pump, with an in-line shutoff
valve located at the pump.

(2) 0-30 psi (0-206.9 kPa) pressure gauge to measure housing pressure.
(3) 0-30 in. Hg (0-101.3 kPa) vacuum gauge to measure transfer pump lift. This gauge should be in

the supply line to the pump, with a shutoff valve between the gauge and the oil source.

(4) A flowmeter for measuring return oil should be used with a three-way valve to permit the

flowmeter to be in use only during the return oil check.

(5) 0°-250°F (-17.8°-121. 1°C) temperature gauge, located at the pump inlet, to monitor inlet

temperature.

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2-33. PRE-1990 (6.2L) FUEL INJECTION PUMP (DB2829-4523) CALIBRATION (Cont’d)

(e) Calibrating nozzles and injection lines:

(1) Eight 0.020-in. (0.5 mm) orifice plate nozzles set at 1700 ± 25 psi (11,721 ± 172 kPa).
(2) Eight 0.093-in. (2.36 mm) inside diameter by 25-in. (63.5 cm) long injection lines.

(f) Calibrating fluid conforming to SAE J967, maintaining a temperature of 110°-115°F (43°-46°C)

at the pump inlet over all speed and load ranges.

(g) Orifice fitting in the inlet line between the supply pump and shutoff valve, to maintain

constant fluid circulation and temperature.

b. Injection Pump Information

NOTE

All speeds are in engine rpm unless otherwise noted.

1. Injection pump operating speed is half of engine speed.
2. Injection pump rotation is counterclockwise.

3. Injection pump is timed to the outlet port in the 10 o’clock position, when viewed from the transfer

pump end.

c. Injection Pump Check (Prior to Service)

1.

2.
3.

4.

5.
6.

7.

8.

9.

Before mounting the pump on the test stand, check the drive shaft for freedom of rotation in the

housing. Pump should be mounted securely in the appropriate adapter, and the intermediate
coupling checked for freedom of movement.
Connect supply and return lines securely.
Install high pressure injection lines. Use copper gaskets or steel washers where required. Leave fuel
line connections at the pump and nozzles loose.
Apply 17.6 V to electric shutoff solenoid and operate pump at 2000 rpm wide-open throttle (WOT)
for 10 minutes to bring to operating temperature and clear air from system.
Tighten all connections securely. Check connections for leaks while operating.
Check fuel delivery at 650 rpm (low idle). Fuel delivery should be 10-18 mm

3

/stroke. If fuel delivery

is not within the range specified, adjust low idle screw. Turn screw clockwise to decrease or counter-
clockwise to increase fuel delivery.
Check housing pressure at 650 rpm, while applying 17.6 V to housing pressure cold advance
solenoid. Housing pressure should be 0-1 psi (0-7 kPa).
Check electric shutoff solenoid for pull-in with 17.6 V maximum with throttle lever in low idle
position at 400 rpm.
Fuel delivery measurement:

(a) In order to minimize variations between readings due to residual oil in the graduates, the

following timed cycle should be used:
(1) Draw

(2) Settle 30 seconds

(3) Drain 30 seconds
(4) Draw

(5) Settle 30 seconds

(6) Read graduates
(7) Repeat cycle and average readings

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