2-35.2. (6.5L) Fuel Injection Pumps (Db2831-5485 Or Db2831-5079) Calibration
TM 9-2815-237-34 · Chapter 2 — Engine Maintenance
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 Test Equipment
General mechanic’s tool kit: Digital tachometer
automotive (Appendix E, Item 1) Voltage source (variable)
Pressure gauge (0-160 psi, 1 psi increments)
Special Tools Pressure gauge (0-30 psi)
Roller-to-roller setting tool Vacuum gauge (0-30 in. Hg)
(Appendix E, Item 45) Flowmeter with three-way valve
Linkage gap tool (Appendix E, Item 49) Temperature gauge (0°-250°F)
Automatic advance indicator Zero-backlash coupling device
(Appendix E, Item 50) Calibrating nozzles and lines
Vacuum valve block gauge Orifice 13211
(Appendix E, Item 51) Calibration stand
Protractor (Appendix E, Item 52)
Air timing gauge (Appendix E, Item 53) Materials/Parts
Holding fixture (Appendix E, Item 46) Calibrating fluid (Appendix B, Item 4)
Torx drive (Appendix E, Item 42) Sealing compound (Appendix B, Item 19)
Manual References
TM 9-2815-237-34P
NOT E
The following calibration procedure applies to 6.5L turbocharged
fuel injection pumps. Refer to para. 2-34 for calibration of 1990
6.2L and above pumps and para. 2-33 for pre-1990 6.2L 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.
(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 0.098-in. (2.5 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
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. 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 should be checked for freedom of movement.
2. Connect supply and return lines securely.
3. Install high-pressure injection lines. Use copper gaskets or steel washers where required. Leave fuel line connections at the pump and nozzles loose.
4. 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.
5. Tighten all connections securely. Check connections for leaks while operating.
6. Check fuel delivery at 650 rpm (low-idle). Fuel delivery should be 10-18 mm3/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.
7. 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) and 8-12 psi (55-83 kPa) when de-energized.
8. Check electric shutoff solenoid for pull-in with 17.6 V maximum with throttle lever in low-idle position at 400 rpm.
9. 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) Energize electric shutoff solenoid and check delivery against the chart below:
THROTTLE MM3/ 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 mm3 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.
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.
d. Injection Pump Settings (Following Pump Repair)
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.
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 mm3/stroke at 650 rpm (fuel reading with cover installed).
14. At 650 rpm, adjust low-idle screw for 13-15 mm3/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 mm3/stroke.
18. Set guide stud for 37.0-39.0 mm3/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 mm3/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.
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 mm3/stroke
maximum.
(2) Re-energize electric shutoff solenoid and check delivery against the chart below.
THROTTLE MM3/ 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 mm3 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.
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.
27. Apply sealing compound as follows: (a) Apply one drop at interface of maximum travel screw and locknut.
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.