Hummer H1 (1992-1998). Instruction - page 40

2-140.8

Change 1

2 - 3 5 . 2 . ( 6 . 5 L ) FUEL INJECTION PUMPS (DB2831-5485 OR DB2831-5079) CALIBRATION (Cont’d)

(b)

Energize electric shutoff solenoid and check delivery against the chart below:

10.

Disconnect pump and mount in holding fixture.

NOTE

Perform step 12 to check pump timing on the DB2831-5079 fuel

injection pump.

11.

Using air timing gauge, check pump timing. Set to 1.5 to 3.5 degrees.

12.

Using air timing gauge, check pump timing. Set to 1.0 +1.0 degrees.

13.

Total throttle travel from low-idle to wide-open throttle should be 75-84 degrees.

14.

Refer to para. 2-7, Engine Troubleshooting, to diagnose any malfunctions encountered during

checkout.

1.

Roller-to-roller dimension must be 1.975 ± .001 in. (50.19 ± .025 mm). With oversize cam ring

installed, roller-to-roller dimension will be 1.882 ± .005 in. (50.34 ± .013 mm). Maximum eccentricity

allowed is 0.008 in. (0.20 mm) TIR.

2.

Linkage gap must be 0.130-0.175 in. (3.30-4.45 mm).

(a)

Mount the pump horizontally in holding fixture and remove governor cover.

(b)

Hold the throttle lever in the wide-open throttle (WOT) position. Rotate pump driveshaft

counterclockwise until a click is heard as the rounded contact points on the governor arm engage the

slots in the thrust sleeve. Continue to rotate driveshaft until gap between governor arm and pump

housing is minimal.

(c)

Using linkage gap tool, check clearance limits between rear of shutoff shaft and vertical tab on

linkage hook.

(d)

If adjustment is required, loosen governor linkage hook adjustment screw and extend the linkage

hook to its maximum open length (throttle lever must be in WOT).

(e)

Insert appropriate step of linkage gap tool between vertical hook tab and throttle shaft, with step

facing shaft. The tool must be held vertically and parallel to linkage hook tab.

(f)

With linkage hook pin seated firmly in governor arm slot and governor arm in the minimal gap

position (step 2.(b)), shorten linkage hook assembly until face of vertical tab is flush against tool.

Tighten adjusting screw to 12-15 lb-in. (1 N

m).

(g)

Recheck linkage gap and adjust if necessary.

d. Injection Pump Settings (Following Pump Repair)

THROTTLE

MM

3

/

CAM MOVEMENT

PRESSURE

RPM

POSITION

STROKE*

(DEGREES)

TRANSFER PUMP

HOUSING

150

Low-idle

36 min.

0-12 psi (0-83 kPa)

400

WOT

57 min.

400

WOT**

4 max.

700

Low-idle

10-18***

3.0 min.

8-12 psi (55-83 kPa)

700

Low-idle

****

0-1 psi (0-7 kPa)**

1800

WOT

65.6-70.5

2000

WOT

3200

WOT

58.5 min.

2.0-4.0

3200

ADJ

21.5-23.5

5.0-7.5

3200

Low-idle

11.0-12.0

3650

WOT

32 min.

3900

WOT

15 max.

* Maximum cylinder variation should be ± 6 mm

3

from the average flow of all cylinders.

** With electric shut-off solenoid de-energized.

*** Reset using low-idle screw.

**** Minimum of 1.25 degrees more than reading.

Change 1

2-140.9

2 - 3 5 . 2 . ( 6 . 5 L ) FUEL INJECTION PUMPS (DB2831-5485 OR DB2831-5079) CALIBRATION (Cont’d)

3.

Set the throttle lever in correct low-idle position prior to calibration using vacuum valve block
gauge. The low-idle screw must be at 34 ± 2 degrees as measured between vertical centerline of
throttle shaft bushing bore and throttle connection stud.

4.

Flush the pump with calibrating oil to remove metal chips and possible contamination.

5.

Before mounting the pump on the test stand, check the driveshaft 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.

6.

Connect supply and return lines securely.

7.

Install high-pressure injection lines. Use copper gaskets or steel washers where required. Leave fuel
line connections at the pump and nozzles loose.

8.

Apply 17.6 V to electric shutoff solenoid and operate pump at 1000 rpm (WOT) for 10 minutes to
bring to operating temperature and clear air from system.

9.

Tighten all connections securely. Check connections for leaks while operating.

10.

Set transfer pump pressure at 2000 rpm (WOT) for 60-62 psi (414-427 kPa); test stand boost should
be set at 5 ± 0.5 psi (34.5 ± 3.4 kPa).

11.

Set return oil flow to 225-375 cc/minute at 2000 rpm (WOT).

12.

Measure housing pressure:
(a)

Check housing pressure at 650 rpm with throttle shaft in low-idle position. Pressure should
be 8-12 psi (55-83 kPa).

(b)

Energize housing pressure cold advance solenoid with 17.6 V. Housing pressure should be
0-1 psi (0-7 kPa).

13.

With governor cover removed and throttle shaft in low-idle position, set min-max governor assembly
for 7-9 mm

3

/stroke at 650 rpm (fuel reading with cover installed).

NOT E

If low-idle screw adjustment is required, refer to step 3. Adjust-
ment is ± 1 turn from the point in step 3.

14.

At 650 rpm, adjust low-idle screw for 13-15 mm

3

/stroke for the remainder of the setting and checking

procedures.

15.

During and at the completion of all settings, ensure face cam to throttle shaft end play measures
0.004-0.006-in. (0.10-0.15 mm) between throttle shaft spacer and housing.

16.

At 1800 rpm (WOT), rotate face cam to its maximum lift position in contact with the cam roller.

17.

Adjust trimmer screw at 1800 rpm (WOT), to advance cam advance and set fuel delivery to
67.5-68.6 mm

3

/stroke.

18.

Set guide stud for 37.0-39.0 mm

3

/stroke at 3650 rpm (WOT). Tighten guide stud nut to 80-90 lb-in.

(9-10 N

m) and check dimension from top of nut to top of guide stud for 0.400-in. (10.2 mm)

maximum.

19.

Set throttle for 22.6 ±0.3 mm

3

/stroke at 1800 rpm and rotate face cam to obtain 5.10 degrees cam

advance.

20.

Tighten face cam screw to 28-30 lb-in. (3 N

m) and check face cam retention.

(a)

Put 0.005-in. (0.127 mm) feeler gauge between throttle shaft mylar washer and housing boss.

(b)

Put throttle shaft in idle position. Squeeze throttle shaft and face cam tightly toward each
other and rotate face cam as lower roller rests approximately in middle at low-idle step.
Tighten screw to 30 lb-in. (3 N

m) with torx bit and remove feeler gauge.

21.

Set total throttle travel. With throttle in low-idle position, align zero degree mark on protractor
with center of rib on rocker lever. Move throttle to WOT and adjust maximum travel screw to
75-84 degrees.

NOT E

Any changes to pump or settings after this point will require
retesting of pump, starting with step 12.

2-140.10

2 - 3 5 . 2 . ( 6 . 5 L ) FUEL INJECTION PUMPS (DB2831-5485 OR DB2831-5079) CALIBRATION (Cont’d)

22.

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

(b)

Check points:
(1)

At 1500 rpm (WOT), de-energize electric shutoff solenoid. Delivery should be 4 mm

3

/stroke

maximum.

(2)

Re-energize electric shutoff solenoid and check delivery against the chart below.

23.

Disconnect pump and mount in holding fixture.

NOTE

Perform step 25 to check pump timing on the DB2831-5079.

24.

Using air timing gauge, check pump timing. Set to +0.25 degree ± 0.50 degree.

25.

Using air timing gauge, check pump timing. Set to 0 ±0.50 degrees

26.

Tighten all fasteners to specifications. Refer to para. 2-32d.

THROTTLE

MM

3

/

CAM MOVEMENT

PRESSURE

RPM

POSITION

STROKE*

(DEGREES)

TRANSFER PUMP

HOUSING

150

Low-idle

37 min.

16 psi (110 kPa) min.

0-12 psi (0-83 kPa)

400

WOT

58 min.

400

WOT**

4 max.

400

Low-idle***

700

Low-idle

12-16

3.5 min.

8-12 psi (55-83 kPa)

700

Low-idle

1.25 min.

0-1 psi (0-7 kPa)

1500

WOT

4 max.

1500

WOT

68.5-69.5

2000

WOT

56 max.

****

60-62 psi (414-427 kPa)

3200

WOT

59.5 min.

2.50-3.60

3200

ADJ

21.5-23.5

5.25-7.25

3200

Low-idle

11-12

3400

WOT

49-52

3.50-4.50

3500

WOT

45 min.

3650

WOT

31.5 min.

3900

WOT

15 max.

125 psi (862 kPa) max.

* Maximum cylinder variation should be ± 6 mm

3

from the average flow of all cylinders.

** With electric shut-off solenoid de-energized.

*** Check electric shutoff solenoid for pull-in with 8.8 volts maximum.

**** Minimum of 1.25 degrees more than reading.

2-140.11

2 - 3 5 . 2 . ( 6 . 5 L ) FUEL INJECTION PUMPS (DB2831-5485 OR DB2831-5079) CALIBRATION (Cont’d)

27.

Apply sealing compound as follows:
(a)

Apply one drop at interface of maximum travel screw and locknut.

CAUTION

Do not allow sealing compound to enter gap between face cam and
housing. Binding of the throttle shaft may result.

(b)

Apply one drop to threaded end of face cam screw where it protrudes from face cam.

(c)

Apply one drop to interface of servo advance adjusting screw and rocker lever, ensuring sealing
compound does not enter hex recess of screw.

28.

Install tamper-proof cap on guide stud.

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