Trouble, Symptom
Test, Check, And/or
and Condition
Probable Cause
Remedy
Engine WILL NOT start.
Cranking speed normal. LOW
OIL indicating lamp on after 5
seconds. (continued)
g.
Faulty fuel pump.
Replace fuel pump if defective.
4.
Engine cranks, but will not
start. LOW OIL indicating
lamp comes on immediately.
a.
Either of two relays, the
bypass relay, K73 (9, Fig.
3), or the low oil pressure
fault relay, K71 (4, Fig. 3),
or the engine control PC
board could be defective.
Attempt to correct this mal-
function by replacing, in
sequence, each of these relays
and the PC board. Replace the
component found to be
defective.
5.
Engine cranks, but will not
start. LOW FUEL indicating
lamp comes on immediately.
a.
Either the low fuel fault
relay, K65 (10, Fig. 3), or
the engine control PC
board is defective.
Attempt to correct this
malfunction by replacing low
fuel fault relay, K65. If this does
not correct the malfunction,
replace the engine control PC
board.
6.
Engine cranks, but will not
start. HIGH TEMPERATURE
indicating lamp comes ON
immediately.
a.
Defective or incorrectly
wired high temperature
switch (S49, located on
engine block on right side).
Check wiring to high tem-
perature switch according to
connection diagram in Chapter
6, and see that wiring is correct.
If wiring is correct, remove
wires and check resistance
between terminals C and N.O.
A resistance of less than 10
ohms indicates a defective
switch. Replace switch if
defective.
b.
Defective over temperature
fault relay, K67 (3, Fig. 3) or
engine control PC board.
Attempt to correct this
malfunction by replacing over
temperature fault relay (K67). If
this does not correct the
malfunction, replace the engine
control PC board.
7.
Engine is HARD to start.
Cranking speed normal, fuel
supply adequate.
a.
Low compression, which
may be caused by any one
of following: Sticking or
burned exhaust valves,
worn or broken
compression rings, leaking
cylinder head gasket, or
improper valve clearance
adjustment.
Check compression in
accordance with instructions in
Cummins Operation Manual.
Overhaul engine to make
repairs as necessary.
OM-2084 / Operation and Maintenance Manual
90CU24 / Series 500392 Generator Sets
Chapter 2-4
November 27/1997
Page 10