Perkins NJ Series Troubleshooting Manual page 198

198
Troubleshooting Section
• "Diagnostics"
• "Diagnostic Tests"
•
"Cylinder Cutout Test"
D. Select the start button at the bottom of the screen
for the cylinder cutout test on the Perkins EST.
E. Select the "Cylinder Cutout Test".
F. Follow the instructions that are provided in the
cylinder cutout test. The cylinder cutout tests are
interactive so the procedure is guided to the finish.
Note: The "Manual Cylinder Cutout Test" is also
available. Access the manual test by selecting the
"Change" button on the screen for the cylinder cutout
test. The "Cylinder Cutout Test" is the recommended
starting procedure. The automated tests run twice
collecting data. The two sets of data are analyzed
and an "OK" or "Not OK" result is displayed.
G. Check for active diagnostic codes and for logged
diagnostic codes that are related to the injector
solenoids.
Expected Result:
All cylinders indicate "OK" on the Perkins EST.
Results:
• OK – All cylinders indicate "OK".
Repair: If the engine is misfiring or if the
engine has low power, refer to Troubleshooting,
"Engine Misfires, Runs Rough or Is Unstable"
and Troubleshooting, "Low Power/Poor or No
Response to Throttle".
If a diagnostic code results from running the
cylinder cutout test, proceed to Test Step 5.
•
Not OK – One or more cylinders displayed "Not
OK" during the test. Proceed to Test Step 5.
Test Step 5. Check the Harness between
the ECM and the Valve Cover Base for an
Open Circuit
Electrical shock hazard. The electronic unit injec-
tor system uses 67-73 volts.
A. Turn the keyswitch to the OFF position. A strong
electrical shock hazard is present if the keyswitch
is not turned OFF.
B. Disconnect the connectors from the valve cover
base.
C. Turn the keyswitch to the ON position.
D. Fabricate a jumper wire 100 mm (4 inch) long with
terminals on both ends of the wire.
E. Insert one end of the jumper wire into the terminal
for the suspect injector's supply. Insert the other
end of the jumper wire into the terminal for the
suspect injector's return circuit.
F. Perform the "Injector Solenoid Test" at least two
times.
G. Repeat this test for each suspect injector. Stop
the "Injector Solenoid Test" before handling the
jumper wires.
Expected Result:
Perkins EST displays "Current Above Normal" for the
cylinder with the jumper wire.
Results:
• OK – The harness between the ECM and the
valve cover base is OK. Proceed to Test Step 6.
•
Not OK – There is a fault between the ECM and
the valve cover base. Proceed to Test Step 7.
Test Step 6. Check the Injector Harness
Under the Valve Cover
Electrical shock hazard. The electronic unit injec-
tor system uses 67-73 volts.
A. Turn the keyswitch to the OFF position. A strong
electrical shock hazard is present if the keyswitch
is not turned OFF.
B. Remove the valve cover.
C. On four cylinder engines, disconnect the harness
from the suspect injector. Disconnect the harness
from the injector that shares the same supply
circuit as the suspect injector.
Note: On four cylinder engines, injectors 1 and 4
share a common injector driver circuit in the ECM.
Injectors 2 and 3 share a common injector driver
circuit in the ECM. If the two injectors that share a
common supply indicate "Open Circuit" fault codes,
the open circuit is probably caused by a faulty ECM.
SENR9982-01