2-34. 1990 (6.2L) FUEL INJECTION PUMP (DB2829-4879) CALIBRATION (Contd)
(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
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 oclock position, when viewed from the transfer
c. Injection Pump Check (Prior to Service)
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 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.
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.
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:
(2) Settle 30 seconds
(3) Drain 30 seconds
(5) Settle 30 seconds
(6) Read graduates
(7) Repeat cycle and average readings