IB16J001C

BULLETIN NUMBER:
IB16-J-001C
IMPORTANT SERVICE
INFORMATION FOR:
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SERVICE MANAGER
SERVICE ADVISOR
TECHNICIAN
PARTS DEPARTMENT
WARRANTY PERSONNEL
ISSUE DATE:
MARCH 2022
GROUP:
ENGINE
CRANK NO START – INSPECT FOR SHEARED CAM PIN
AFFECTED VEHICLES

2012MY – current Isuzu N-Series
Equipped with 6.0L Gas V-8 Engines
This bulletin supersedes information bulletin IB16-J-001B. This bulletin is being revised
to update the Model Years. Please discard previous bulletin IB16-J-001B.
INFORMATION
Some customers may experience a “Crank No Start” condition in the vehicles listed
above. The following diagnosis might be helpful if the vehicle exhibits the symptom(s)
described in this Information Bulletin.
Condition/Concern
On rare occasions, a crank no start may be encountered on a 6.0 V8 engine.
During diagnosis, the technician will find proper fuel pressure, spark from each spark plug
wire, and proper injector pulse. However, the following concerns will be noted during their
diagnosis: low static compression, excessive cylinder leakage past an intake or exhaust
valve, the engine may start but run poorly if the CMP sensor is disconnected, and/or the
valve train may not move while cranking the engine.
This concern may be the result of a sheared camshaft sprocket locating pin due to the
camshaft seizing to the camshaft bearings at one time.
Recommendation/Instructions
If this concern is encountered, the following diagnostic steps should be performed as
necessary:
1.
Crank the engine while checking for movement in the valve train. This can be done
by shining light down the oil fill tube on most models. If the valve train appears to be
moving normally while the crankshaft is turning, continue to step 2. But, if you determine
valve train is not moving while the crankshaft is turning, continue to step 4.
2.
Disconnect the CMP sensor to see if the engine will start. If the engine starts,
continue to step 4.
3.
Perform the following WSM diagnostic procedures as necessary:
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Engine Cranks But Does Not Run diagnostics in WSM
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Engine Compression Test in WSM (document results)
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Cylinder Leakage Test in WSM (document results)
If the WSM procedures above isolate an engine mechanical concern (low
compression; excessive cylinder leakage through the exhaust or intake, any type
of valve train damage, etc.), continue to step 4.
4. If you have completed steps 1, 2, or 3, remove the front cover to inspect for a sheared
cam sprocket locator pin. See sheared cam locator pin in Figure 1 below.
5. If it is determined the cam sprocket locator pin has sheared the engine assembly will
need to be replaced. Technicians are to contact the IQC per bulletin IB09-X-001E. Follow
the instructions provided from the IQC to complete the repair.
Warranty Information
For vehicles repaired under warranty, please use the appropriate warranty labor
operation.
Please follow this diagnostic or repair process thoroughly and complete each step. If the
condition exhibited is resolved without completing every step, the remaining steps do not
need to be performed.
Figure 1