TM 55-2840-241-23
Table 4-1. Troubleshooting (Continued)
Item
Trouble
Probable cause
Remedy
2
c. Failed spark igniter.
(cont)
d. Failed ignition exciter.
e. Spark igniter firing
intermittently.
3
4
5
Engine fails to light
off vapor coming
out of exhaust and
ignition operation
audible.
Engine fails to light
off no fuel vapor
coming out of
exhaust.
Engine lights off but
will not accelerate to
idle speed in 45
seconds.
Water or other
contaminants in fuel.
a. No fuel in tanks.
b. Insufficient fuel
pressure to engine fuel
pump.
c. Gas producer fuel
control in cutoff position.
d. Fuel pump
inoperative.
e. Fuel nozzle valve
stuck.
f. Fuel nozzle orifice
clogged.
g. Air fuel lines.
h. Fuel check valve
stuck.
a. Inadequate starter
torque caused by low
battery or defective
starter-generator.
c. Replace igniter. (Refer to para
5-36.)
d. Replace exciter. (Refer to para
5-35.)
e. Check input voltage to exciter, If
voltage is low, check battery. If
voltage is not low, replace exciter.
Check a sample of fuel from the
bottom of the tank. If contaminated,
defuel the tank (Refer to TM
55-1520-228-23). Disconnect fuel
line at the fuel nozzle then flush the
system with clean fuel. Install new
filters in the fuel pump and fuel
control.
a. Fill tanks with fuel.
b. Turn on aircraft boost pump.
c. Check linkage.
d(1). Check pump for sheared drives
or internal damage and replace as
required. (Refer to para 5-9).
d(2). Check for air leaks at pump
e. Replace nozzle. (Refer to para
5-15).
f(1). Check fuel filter. (Refer to para
5-l0.)
f(2). Replace nozzle. (Refer to para
5-15.)
g. Bleed system and try a second
start.
h. Replace check valve. (See Figure
5-2).
a. Check condition of battery and
starter-generator to determine if
sufficient N1 cranking speed is
attainable.
4-2
Change 23
b. Air leaks in control
air tubing.
b. Check air tubes and fittings for
looseness or cracks. Replace or
tighten tubes and fittings as required.
If cracked engine mounting pads are
suspected, refer to TM 1-1520-254-23,
Technical Manual Aviation Unit Maintenance
(AVUM) and Aviation Intermediate Maintenance
(AVIM) Manual Nondestructive Inspection
Procedure for OH-58 Helicopter Series.
