3-93. ON-ENGINE FUEL PUMP ADJUSTMENT (Contd)
Spring retainer (12)
10. New shim(s) (13)
Add or remove from behind
Each 0.001 in. (0.025 mm) shim
spring (14). High speed adjust-
thickness will change speed
ment should be 2130 to
approximately two rpm.
11. Spring retainer (12) and
Install on guide (15).
Use snapring pliers. Make certain
shim(s) (13) do not slip off of guide
12. Spring pack cover (9)
Secure with three captive
Tighten screws (6) and (8) to
washer screws (6), screw (8),
9-11 lb-ft (12-15 Nm). Screw (8)
and four washers (5).
has hole drilled through head for
sealing wire insertion.
d. High Idle Speed Adjustment
Do not use this check to make governor speed adjustments. If no-load speed is much
greater than specifications, examine governor for malfunction or faulty parts.
13. Engine (1)
a. Operate to purge air from fuel
system and bring up to operating
b. Bring to full throttle and hold.
Speed should be 10-12 percent
Note maximum rpm.
greater than governor speed
cutoff point. If on-engine fuel
pump adjustments made with
engine mounted in vehicle, rpm
will depend on engine parasitic
loads (fan, pumps, etc.).
e. Checking and Adjusting Fuel Rail
It should not be necessary to adjust fuel rail pressure on a newly calibrated fuel pump
more than ± 2 psi (± 14 kPa). If adjustments greater than this are required, fuel pump test
stand, injector test stand, or engine problems may exist. Do not remove throttle shaft ball
unless fuel rail pressure adjustment needs to be performed.
The correct method of checking engine fuel rail pressure is with engine installed on a
chassis or engine dynamometer.
14. Governor speed cutoff
Check setting point.
Adjust, if necessary.
15. Fuel rail pressure gauge (19)
Install between fuel supply
elbow (18) on fuel pump assembly
(3) and female union tee (17).
Bring to full throttle load until
Accurate tachometer must be
rpm falls to rated speed.
used to measure rpm.
17. Fuel rail pressure gauge (19) Note reading.
If pressure is above or below the
minimum specification, do step 18.
If OK, go to step 19.