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Section 7
DIAGNOSTIC TESTS
Figure 7-44. – Oil Pressure Switch
PROCEDURE:
1. Check engine oil level. If necessary, replenish oil
level to the dipstick “FULL” mark.
2. Set a VOM to its “Rx1” scale and zero the meter.
3. Connect the meter test leads across the switch
terminals, with engine shut down. The meter
should read
“
Continuity”. A small amount of resis-
tance is acceptable.
4. Crank the engine. Oil pressure should open the
switch contacts at some point while cranking and
starting. Meter should then indicate “Infinity”.
5. If the contacts did not open in Step 5, remove
the low oil pressure switch and connect an oil
pressure gauge in it’s place. Start the engine and
measure oil pressure. Pressure should be above
10 psi.
RESULTS:
1. In Step 3, if “Continuity” is not indicated, replace
the switch.
2. If oil pressure checked good in Step 5, but Step
4 measured “Infinity,” replace the low oil pressure
switch.
3. If oil pressure is below 10 psi, determine cause
of low oil pressure. Verify that the oil is the proper
viscosity for the climate and season.
4. If all steps check GOOD, go to Test 37.
TEST 37 – CHECK WIRE 86 FOR CONTINUITY
PROCEDURE:
1. Disconnect the J1 Connector from the Printed
Circuit Board.
2. Locate Pin Location J1-6 on the harness end of
the J1 Connector.
3. Remove Wire 86 from the Low Oil Pressure switch
(LOP).
4. Set a VOM to its “Rx1” scale and zero the meter.
5. Insert one meter test lead into the end of Wire 86
disconnected from the LOP. Insert the other meter
test lead into Pin Location J1-6 on the harness
end of the J1 Connector.
RESULTS:
1. If “Continuity” is not indicated, repair or replace
Wire 86.
2. If “Continuity” is indicated, replace the Printed
Circuit Board.
TEST 38 – TEST OIL TEMPERATURE SWITCH
DISCUSSION:
If the engine cranks, starts and then shuts down,
one possible cause of the problem may be a high oil
temperature condition. Protective shutdown is a nor-
mal occurrence if the oil temperature switch exceeds
approximately 270° F for gasoline units, or 284° F for
LP units.
Figure 7-45. – Oil Temperature Switch
PROCEDURE:
1. Remove Wire 85 from Oil Temperature Switch
terminal and start the generator. If engine starts
and runs now, but shuts down when Wire 85 is
connected to the switch terminal, the following
possibilities exist:
a. Oil temperature is too high.
b. The oil temperature switch has failed closed or
is shorted to ground.
2. Remove the switch and place its sensing tip into
oil (Figure 7-46). Place a thermometer into the oil.
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