FUEL SYSTEM ABNORMAL CONDITIONS
Engine fuel supply pump defective.
Fuel Pressure Check
Install pressure test gauges:
100 psi gauge in fuel/water separator filter cover bleeder valve
opening (WP 0084, Fuel/Water Separator Automatic Drain
System and Wiring Harness Replacement).
10 psi gauge in primary filter cover bleeder valve opening
(WP 0086, Primary Fuel Filter Repair and Element
Turn master and in-tank fuel
pump switches "ON".
Operate engine at high-idle
speed (2500-2640 rpm).
40 psi at fuel/water separator
filter, and below 1 psi at
primary fuel filter.
Primary filter restriction.
Element dirty or clogged.
(2) Repair or replace defective fuel pump
assembly (refer to pertinent fuel pump
Fuel pump failure (insufficient
fuel output due to defective regulating
valve, internal pump wear or shaft seal leak
causing fuel leakage into engine oil).
(3) Drain oil and replace filters in engine
(WP 0031, Engine Oil Replacement, and
WP 0073, Oil Filters Replacement).
Fuel injector nozzle defective.
a. Abnormal spray pattern (sticky action, stuck
partially open, or orifices partially plugged).
(1) Locate faulty cylinder as follows:
Perform High Pressure Fuel
Check on one cylinder at a time
with engine idling (all engine
Note cylinder on which no
change in engine operation
occurs, or if cylinder misfire
Cylinder is not firing due to
Alternate check with power
at idle speed.
Note if cylinder temperature is
cold (by touch) at intake port
area of cylinder head.
A cold cylinder indicates the
cylinder is not firing due to
WP 0020 00-9