14-100
FUEL
SYSTEM
•
DIESEL
FUEL
INJECTION
SYSTEM DIAGNOSIS
SYMPTOM CAUSE
ACTION
Starting problem Improper
fuel
Drain
fuel
tank,
flush
system,
fill
with
proper
fuel.
Change
filter
Empty
fuel
tank
or
fuel
tank
vent
blocked
Fill
tank, bleed system, check
tank
vent
Air in
fuel
system Bleed
fuel
system
Voltage not supplied to
fuel
solenoid or
fuel
solenoid
inoperative
Correct voltage supply problem or
replace solenoid
Clogged
fuel
filter
Replace
fuel
filter
Restricted or blocked
fuel
supply lines Remove restriction or replace lines
Leaking
injection
lines, damaged lines or
loose
connections Replace damaged lines or tighten
connections as necessary. Bleed
fuel
system
Wax buildup in
fuel
filter
(cold
weather
only) Replace
fuel
filter,
use recommended
diesel
fuel
Incorrect
injection
pump to engine timing Adjust
injection
pump timing
Malfunctioning air heating system Repair air heating system
Injection
sequence does not correspond
with
firing
order Install
fuel
injection
lines in correct order
Malfunctioning
KSB
valve Replace
injection
pump
Low or uneven engine compression Repair as necessary
Restricted or blocked
fuel
injection
lines Remove restriction or replace lines
Fuel
injection
pump malfunction or not adjustable Replace
fuel
injection
pump
Engine
Surge at
idle
Empty
fuel
tank
or
fuel
tank
vent
blocked
Fill
tank, bleed system, check
tank
vent
Air in
fuel
system Bleed
fuel
system
Low
idle
speed Adjust
idle
speed
J9H4-22
FUEL
SYSTEM
14-103
DIESEL FUEL
INJECTION
SYSTEM DIAGNOSIS-CONTINUED
SYMPTOM
CAUSE
ACTION
Excessive
fuel
consumption improper diesel
fuel
Use
correct
fuel
for conditions. Refer
to
owner's manual
Incorrect injection pump timing
Adjust
injection pump timing
Restricted or damaged
injector
nozzle Repair or replace as necessary
Clogged
or
restricted air
filter
Remove
restrictions or replace air
filter
if
necessary
Injection sequence does not correspond
with
firing order install
fuel
injection lines in correct order
Intercooler internally blocked
or
leaking
Check
pressure drop
across
intercooler.
If
pressure drop
is
more than
4
in. Hg,
clean or replace as necessary
Low
idle misadjusted
Adjust
idle stop screw
Malfunctioning
KSB
valve
Replace
injection pump
Incorrect injection pump to engine timing
Adjust
injection pump to engine timing
Fuel injection pump malfunction or
not adjustable
Replace
fuel
injection pump
Unabie to shut engine off Voltage to
fuel
solenoid
interrupted
or
fuel
solenoid
inoperative Correct voltage supply problem or
replace
solenoid
Either poor
performance,
black moke
or
low power Improper
fuel
Drain
fuel
tank, flush
system,
fill
with
proper
fuel
for conditions. Refer to owner's
manual
Air
in
fuel
system
Bleed
fuel
system
Intercooler internally blocked
or
leaking
Check
pressure drop
across
intercooler.
If
pressure drop is more than
4
in. Hg,
clean
or
replace
as
necessary
Restricted or blocked
fuel
injection lines
Remove
restrictions or replace lines
Incorrect injection pump timing
Adjust
injection pump timing
Restricted or damaged
injector
nozzle
Repair
or replace as necessary
Clogged
or restricted air
filter
Remove
restrictions or replace
filter
if
necessary
Air
fuel
control tube leaking or broken Repair or replace as necessary
Low
manifold pressure
Check
and repair turbocharger operation
Injection sequence does not correspond
with
firing order Install
fuel
injection lines in correct order
—
Low
or uneven engine compression
Repair as necessary
J9114-255
