F-16FuelControl_TestInstruction.pdf.pdf

TO 6J3-5-4-3

8-1

CHAPTER 8

TESTING

8.1 GENERAL.

This chapter includes procedures for testing and troubleshooting of the fuel control assembly.

8.1.1 General Checkout Instructions.

a. Table 8-1 is a data sheet to be kept as a record of test. All blanks on the data sheet imply a required recording to be filled in by the test operator.

If unable to achieve any testing parameters, refer to troubleshooting Table 8-4.

Ensure that torque seal paint is applied as per Figure 8-6 after adjustments have been made.

Tool used for adjustments can either be the hex-head or t-handle, as per the drawing No.

44459-8.

8.1.2 Test Equipment Requirements.

Fuel Pump shaft rotation shall be counterclockwise when viewing the drive shaft end. Failure to observe may cause component malfunction.

a. Test stand shall provide filtered calibration fluid as specified in Table 2-2 at a temperature of 70 (±10) °F.

b. Fuel Pump shaft rotation shall be counterclockwise when viewing the drive shaft end.

c. Test stand shall provide 4.2-10 mA dc for

Bias control and 24-28 Vdc for MAX and

START solenoid control. Refer to Figure 8-

1, sheet 2 for wiring schematic.

d. Orifice SZ90222 (alternate JET1875600D) provides 15 pph flow at 100 psid and orifice

SZ90220 (alternate JEHB1872450L) provides 165 pph flow at 100 psid.

8.1.3 Bench Test Setup. (Figure 8-1). Refer to TO

33D4-6-332-1 or Publication No. SE-876-03-1053 for test stand operation procedures.

a. Mount fuel control drive pad, part of

102187-51-5 kit, on fuel accessory test stand.

b. Mount fuel control assembly on fuel control drive pad using two bolts and nuts (part No.

NAS 1352-4-52P or equivalent).

c. Remove tube assembly (12) and fitting (65).

Install fuel control relief valve adjusting tool

(ST93486).

d. Make all connections between fuel control and test stand according to Figure 8-1, Sheet

2.

8-2

8-3

8-4

8-5

8.2 ADJUSTMENTS.

Refer to Figure 8-2 for location of adjustments.

Perform adjustments as follows:

Replace cap following each adjustment of bias spring adjustment screw whenever CDP is greater than zero.

a. Turn altitude compensator adjustment screw

(49) counterclockwise until it stops.

b. Turn ratio adjustment screw (43) fifteen turns clockwise to prevent pump cavitation.

c. Operate fuel control unit at the 4200 rpm setting according to conditions in Table 8-1.

d. Run until system is purged of air.

e. Operate fuel control unit on the 3800 rpm setting then the 4222 rpm setting according to conditions in Table 8-1. Run on the 4222 rpm setting for at least five minutes.

Leakage from drain port shall not exceed 4 drops per minute. No other external leaks permitted.

1) If leakage exceeds requirements, refer to troubleshooting table 8-4.

8.3 PRELIMINARY PRESSURE RELIEF VALE SETTING.

a. Operate fuel control unit according to conditions in Table 8-1.

b. Adjust fuel control relief valve with installed fuel control relief valve adjusting tool

(ST93486) for correct pump discharge pressure. Clockwise adjustments result in an increase in pressure.

8.4 START FLOW SETTING.

a. Operate fuel control unit on the 3000 rpm

b. Turn ratio adjustment screw (43) counterclockwise until no further change in

ΔP occurs. Back out bias spring adjustment screw (45) until no further change in ΔP occurs.

c. Operate fuel control unit on the 1500 rpm

d. Adjust ratio screw (43) to obtain specified

ΔP. This is an initial setting. A drift of 1-2 psid during test is normal.

8.5 ACCELERATION SETTING.

conditions in Table 8-1, making adjustments to the bias spring adjustment screw (45) and ratio adjustment screw (43) to bring flows into range.

b. Successive adjustments on each of the three settings may be necessary to achieve all required flow ranges.

8.6 MAXIMUM FLOW INITIAL ADJUSTMENT.

The maximum flow must be approached with the governor orifice alignment screw (26) being turned in the clockwise direction. If over adjusted, back out the adjustment screw and start over.

b. Adjust ratio screw (43), if necessary to obtain required flow in Table 8-1. If adjustments to the ratio screw (43) are not successful in obtaining the required flow, adjustments to the governor orifice alignment screw (26) may be necessary.

Clockwise adjustments increase the flow.

c. If flow drops off before 3900 rpm, use tool

ST94063 and a hex wrench in conjunction to adjust outside speeder spring sleeve and inner differential speed adjustment screw.

8.7 DIFFERENTIAL SPEED AND RELIEF VALVE

ADJUSTMENT

8-6

b. Set differential speed adjustment screw to obtain required flow. If necessary reset fuel control relief valve with ST93486 to obtain necessary pump discharge pressure.

8.8 MINIMUM FLOW CHECK.

conditions in Table 8-1. Check required flow.

8.9 BIAS CONTROL CHECK.

conditions in each of the steps in Table 8-1 in the order listed. Note the following:

1) If 1500 rpm flow is not within limits, adjust ratio screw (43).

2) If 3000 rpm flow is not within limits, adjust acceleration needle adjustment

(30).

3) If 3800 rpm flow is not within limits, increase CDP to 40 (±2) psig and adjust acceleration needle adjustment (30) to obtain a fuel flow of 106 to 112 pph.

4) After all changes to the acceleration needle adjustment, tighten nut (31) just enough to prevent it from backing off and changing the setting.

8.10 ALTITUDE COMPENSATION ADJUSTMENT.

b. Rotate altitude compensator adjustment screw (49) clockwise until ΔP decreases by

0.5 to 1.0 psi. Torque nut on compensator adjustment screw to 24 to 27 inch-pounds.

c. Adjust bias spring adjustment screw (45) to return ΔP to the value recorded in step a.

d. Recheck flows for 1500, 3000, and 3800 rpm points in paragraph 8.10.

1) If flows are out of tolerance, adjust ratio adjustment screw (43) ±¼ turn maximum, the acceleration needle adjustment (30) ±2 turns maximum, and/or the altitude compensator adjustment screw (49) ±¼ turn maximum to obtain correct flow readings.

e. Recheck fuel flows in accordance with paragraphs 8.6, 8.8, 8.9, and 8.10.

8.11 BIAS CONTROL ADJUSTMENT.

conditions in each of the two steps in Table

8-1. If any adjustments need to be made:

1) Use tool ST94063 and a hex wrench in conjunction to adjust outside speeder spring sleeve and inner differential speed adjustment screw.

b. Remove current to servo valve. Repeat paragraph 8.8, resetting differential speed adjusting screw as necessary.

c. If adjustments were performed, repeat paragraph 8.12.

8.12 CALIBRATION CHECK.

a. Connect line from test stand to Altitude

Simulation Connection.

b. Sea Level and Altitude calibration pressures are specified in Table 8-1 in terms of absolute pressure. Positive or negative

(vacuum) pressure may be required to be applied to the Altitude Simulation port depending on the elevation of testing.

c. Operate fuel control unit according to conditions in Table 8-1. Perform Sea Level points first then altitude. Subtract the two for the specified difference in Table 8-1. All points must be in limit, otherwise make

d. If adjustments are necessary, refer to paragraph 8.6 instructions.

8.13 CALIBRATION SCHEDULE.

8-7

b. If adjustments are necessary, refer to paragraphs 8.8 and 8.12 instructions.

8.14 BURST TEST.

conditions in Table 8-1. Adjust rpm as necessary to achieve flow.

b. Ensure flow increases as required once

MAX solenoid is engaged.

8.15 HYSTERISIS CHECK.

b. Record rpm and fuel flow at 4222 rpm setting.

c. Decrease speed to below 4000 rpm.

d. Increase rpm until initial flow is met. Record rpm and flow.

e. Increase rpm to above 4400 rpm.

f. Decrease rpm until initial flow is achieved.

Record rpm and flow.

g. Calculate differences as specified in Table

8-1.

8.16 DROOP CALIBRATION SCHEDULE.

8.17 PRESSURE RELIEF VALVE CHECK AT LIGHT-

OFF.

8.18 POST-TEST PROCEDURES.

a. Remove ST93486 (fuel control relief valve adjusting tool). Install fitting (65) and torque

50 to 60 inch-pounds.

b. Install plug (33) into housing assembly (38) and torque 90 to 100 inch pounds. Torque nut (31) 55 to 70 inch-pounds.

c. Apply assembly fluid to threads of fitting

(65) and reducer (18). Install tube assembly

(12). Torque nuts of tube assembly (12) 75 to 85 inch-pounds.

d. Apply thread compound, Loctite 569-31 to plugs (2) and (3). Torque plugs (2) and (3)

135 to 150 inch-pounds.

8.18.2 Preservation.

a. Use grade 1010 oil, filtered through a 10 micron filter. Cap all ports, except the Input

Boost port and the Main Fuel Out port.

b. Run the fuel control at 10 rpm while adding oil to the Input Boost port. Continue adding oil until it flows of the Main Fuel Out port.

c. Reduce test stand drive speed and oil pressure to zero.

d. Disconnect and remove fuel control from test stand.

e. Drain fuel control unit of oil.

8.18.3 Bellows Assembly Seal.

Refer to Figure 8-5.

a. Remove cap (34) and packing (35). Discard packing.

b. Insert hypodermic needle filled with thread locking compound per MIL-S-46163 into cavity of diaphragm retainer stud. Put needle through diaphragm adjusting screw hole until needle hits the tip of the ratio adjusting screw (43) as shown in Figure 8-2 and 8-5.

c. Inject two drops or 0.03 cc of thread locking compound.

d. Allow thread locking compound to cure for

24 hours.

8-8

e. Install cap (34) and new packing (35) into bellows assembly. Torque 75 to 85 inch-pounds.

f. Connect air supply to CDP port. Connect hose from Altitude Simulation port into a cup of water (See Figure 8-5).

g. Pressurize CDP port with 15 (±5) psig of air for at least one minute. No leakage is allowed seen in the form of bubbles.

h. If leakage is detected, repeat steps a. through g.

8.18.4 Torque Seal and Safety Wire.

If needed, excess oil from preservation may be removed using isopropyl alcohol and a clean cheesecloth.

a. Apply torque seal paint, part No. F-900, to the areas shown in Figure 8-6. The areas must be non-oily and dry.

b. Safety wire cap (34), sleeve (27), and needle valve (62).

c. If not previously accomplished during inspection/repair, apply Loctite 222 on screws (124).

8.19 TROUBLESHOOTING.

The troubleshooting procedures presented in this chapter are arranged in the same order as the checkout procedures. When a malfunction is noted, refer to Troubleshooting Table 8-4, and perform the procedures outlined under the appropriate step. For repairs refer to REPAIR AND REPLACEMENT (Chapter

5). After repairs are completed, perform an operational checkout to ensure that unit is serviceable.

Table 8-1 Data Sheet (Sheet 1 of 3)

S/N: _______________ Technician: ________________ Date: _________________

Par.

No. Test

Fuel Inlet (psig)

Drive Speed (rpm)

CDP

(psig)

MAX/

START

Switch

Bias Current (mA DC)

Altitude Simulator Pressure

(psia) Flow (pph)

Pump Discharge Pressure

(psig)

ΔP

(psi)

8.2 Adjustments 20 (±5)

(±50)

46 (±2) START

4.2 - 10

14.7 (±0.2)

(±50)

OFF

8.3 Preliminary

Pressure Relief Valve Setting

20 (±5)

(±100)

0 START OFF 14.7 (±0.2)

500-550

8.4 Start Flow

Setting 20 (±5)

(±100)

0 START OFF 14.7 (±0.2)

25-30

8.5 Acceleration

Setting 20 (±5)

(±50)

START OFF 14.7 (±0.2)

48-53

(±10)

15 (±2) 74-78

40 (±2) 106-112

8.6 Maximum Flow

Initial Adjustment

20 (±5) (±50)

46 (±2) MAX OFF 14.7 (±0.2)

281 min

8.7

Differential Speed and Relief

Valve Adjustment

20 (±5) (±5)

46 (±2) MAX OFF 14.7 (±0.2)

195 (±5)

560 (±10)

8.8 Minimum Flow

Check 20 (±5)

(±10)

46 (±2) MAX OFF 14.7 (±0.2) 35-60

8.9 Bias Control

Check 20 (±5)

(±5)

46 (±2) MAX

OFF

14.7 (±0.2)

Record (a)

(±5)

4.2 - 10 (a)+90 min

START OFF

48-53

15 (±2) 74-78

35 (±2) 100.5-106

8.10 Altitude

Compensation Adjustment

20 (±5) (±50)

0 START OFF 14.7 (±0.2)

8.11 Bias Control Adjustment

20 (±5)

(±2)

46 (±2) MAX

OFF

14.7 (±0.2)

195 (±5)

(±2)

4.2 - 10 215 (±5)

Table 8-1 Data Sheet (Sheet 2 of 3)

S/N: _______________ Technician: ________________ Date: _________________

Par.

No. Test

Fuel Inlet (psig)

Drive Speed (rpm)

CDP

(psig)

MAX/

START

Switch

Bias Current (mA DC)

Sea Level Altitude

Simulator Pressure

(psia)

Sea Level Flow (pph)

Altitude Simulation Pressure

(psia)

Altitude Flow (pph)

Altitude Flow

Minus Sea Level Flow

(pph)

8.12 Acceleration Sea Level Calibration

20 (±5)

(±50)

START OFF 14.7 (±0.2)

48-53

6.75 (±0.2)

60 max

2 min

1 (±2) 48-54.5

61.5 max

2 min

2 (±2) 50-56.5

63 max

2 min

2.5 (±2) 51.5-57

64 max

2 min

3 (±2) 52.5-58

65 max

2 min

4 (±2) 55-59.5

67 max

2 min

5 (±2) 57-61.5

68 max

2 min

(±50)

10 (±2) 66-70

76 max

2 min

(±50)

15 (±2) 74-78

83 max

2 - 7

(±50)

20 (±2) 81.5-85.5

90 max

2 min

(±50)

25 (±2) 88-93

97 max

2 min

(±50)

30 (±2) 94.5-100

104 max

2 min

35 (±2) 100.5-106

110 max

2 min

40 (±2) 106-112

(+2/-0)

(a) ± 2

60 max

Par.

No. Test

Fuel Inlet (psig)

Drive Speed (rpm)

CDP

(psig)

MAX/

START

Switch

Bias Current (mA DC)

Flow (pph)

8.13 Calibration Schedule

20 (±5)

(±50)

46 (±2) MAX

OFF

281-321

251-276

189-210

115-142

35-60

4.2 - 10

269 min

221-243

199-222

133-168

(±10)

37-85

Table 8-1 Data Sheet (Sheet 3 of 3)

S/N: _______________ Technician: ________________ Date: _________________

Par. No. Test

Fuel Inlet (psig)

Drive Speed (rpm)

CDP

(psig)

MAX/

START

Switch

Bias Current (mA DC)

Flow (pph)

Pump Discharge Pressure

(psig)

8.14 Burst Test 20 (±5)

4350-4450

OFF

OFF

60 (±2)

MAX

increase 15 max

8.15 Hysteresis Check

20 (±5)

4222 (±2) (a)_______

46 (±2) MAX OFF

Record (d)_______

4000 max

(b)_______

(d)

4400 min

(c)_______

(d)

Difference between (a) and (b) less not greater than ±30 rpm

Difference between (a) and (c) less not greater than ±30 rpm

8.16 Droop

Calibration Schedule

20 (±5)

4500 (±2)

46 (±2) MAX OFF

31-50

4450 (±2) 34-60

4400 (±2) 39-75

4350 (±2) 61-100

8.17 Pressure Relief at

Light-Off

20 (±5) 500 (±10) 0 START OFF

100 min

8-4

8-5

8-6

CDP

PUMP DISCHARGE

PRESSURE PORT