IB12-J-003C

BULLETIN NUMBER:
IB12-J-003C
IMPORTANT SERVICE
INFORMATION FOR:
 SERVICE MANAGER
 SERVICE ADVISOR
 TECHNICIAN
 PARTS DEPARTMENT
 WARRANTY PERSONNEL
ISSUE DATE:
AUGUST 2016
GROUP:
ENGINE
LONG BLOCK REPLACEMENT – FUEL INJECTOR PIPE
INSTALLATION
AFFECTED VEHICLES
 2005MY - Current Isuzu N-Series
 2005-2010MY GMC and Chevrolet W-Series
Equipped with 4HK1 5.2L Diesel Engine
 1999-2009MY Isuzu F/H Series
 1999-2009MY GMC and Chevrolet C/T Series
Equipped with 6HK1 7.8L Diesel Engine
 2011MY -Current NPR/NPR Stripped Chassis (Reach)
Equipped with 4JJ1 3.0L Diesel Engine
This bulletin supersedes IB12-J-003B. This bulletin is being revised to update
Model Years and Models. Please discard bulletin IB12-J-003B.
INFORMATION
Proper Installation of the Fuel Injector Pipes into a Long Block Assembly
The fuel injection pipes should be installed onto the new long block assembly after first
installing the common rail.
When installing the fuel injection pipes, follow the procedure below to ensure proper
mating of the fuel injector high pressure inlet, and the fuel injection pipes.
NOTE: Fuel injector pipes must not be reused. New pipes must be installed anytime the
fuel injector pipes are removed. Failing to replace pipes and/or follow the procedure
below may cause severe engine damage.

Program the fuel injector flow rates found on the cylinder head cover into the
ECM using IDSS (if applicable).

Remove the cylinder head cover taking care to avoid damage to the gasket.

On 4HK1 and 6HK1 engines only: loosen and remove the fuel injector terminal
nuts.

On 4HK1 and 6HK1 engines only: loosen and remove the fuel injector harness
bracket bolts. Unclip the harness at the inside of the pass through connector.
Remove the bracket and wire harness.

On 4HK1 and 6HK1 engines only: remove the fuel injector leak off pipe. Discard
the gaskets.

Loosen but do not remove the fuel injector clamp fixing bolts.

Ensure there is clearance between the fuel injector and the fuel injector clamp by
gently rotating the fuel injector side to side.

Apply engine oil to the outer diameter of the threads of the fuel injectors and the
common rail pipe fittings. Loosely thread the fuel injection pipe sleeve nuts to the
correct fuel injector and the correct location on the common rail.

On 4HK1 and 6HK1 engines only: loosely install the fuel injection pipe clips.

HAND TIGHTEN the fuel injector and common rail sleeve nuts until contact is felt
between the pipe and the fuel injector, and pipe and common rail fitting.
NOTE: Pay close attention to ensure the fuel injection pipe is positioned correctly
into the fuel injector high pressure inlet.

Torque the fuel injection piping in the following order. Refer to the appropriate
service manual for detailed torque specifications.
o Fuel injector clamp bolts.
o Fuel injector pipe sleeve nuts to the fuel injectors.
o Fuel injector pipe to the common rail.
o On 4HK1 and 6HK1 engines only: install the fuel injector leak off pipe with
new gaskets and tighten the banjo bolts.
o On 4HK1 and 6HK1 engines only: clip the fuel injector harness passthrough connector on and install the harness bracket.
o On 4HK1 and 6HK1 engines only: install the fuel injector terminal nuts.
o On 4HK1 and 6HK1 engines only: torque the fuel injection pipe clips.
NOTE: On 4HK1 and 6HK1 engines install the cylinder head cover from the original
engine to ensure the correct engine emission label and information will be retained
with the vehicle. Because 4JJ1 equipped vehicles have the emissions labels
installed on the body of the vehicle, switching the cylinder head cover is not
necessary.
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