Komatsu 830E-AC Shop Manual page 200

Problem
• Cranking motor has very long prelubrication cycle.
• Cranking motor has no prelubrication, no delay
and no crank.
• Cranking motor prelubricates, delays, then does
not crank.
D2-10
Except for severe cold weather starts, the prelube
cycle should not exceed 45 seconds.
a. Low oil pressure.
b. Make sure oil of the proper viscosity is being
used in respect to outside temperature. (Refer
to engine manufacturer's specifications).
c. Check for suction side air leaks, loose con-
nections, cracked fittings, pump casting, or
hose kinks and blockage.
d. Check the oil pressure switch for the correct
location. Be certain that it has not been
moved into a metered oil flow, as in a bypass
filter or governor assembly.
If the cranking motor is totally inoperative and no pre-
lubrication, no delay and crank, this indicates a possi-
ble failure of the prelubrication timer solenoid.
Remove the wire from the pressure switch (ground
wire) and activate the key switch for several seconds.
a. If the cranking motor delays - then cranks, the
Prelube Timer Solenoid is bad. Replace the
timer solenoid assembly.
b. If the cranking motor is still inoperative, check
the truck cranking motor switch circuit. Make
sure proper voltage is available to the Prelube
Timer Solenoid when the key is activated.
Indication is either a timer failure, or a cranking motor
problem.
a. Place a jumper wire to the cranking motor
solenoid "S" post. If the engine starts to crank,
replace the Prelube Timer Solenoid.
b. If the engine fails to crank when the "S" post
is energized with voltage, check out cranking
motor bendix solenoid and cranking motor
pinion drive.
24 VDC Electric Supply System
Probable Cause
D02034