start ISUZU KB P190 2007 Workshop Repair Manual

6E–270 ENGINE DRIVEABILITY AND EMISSIONS
FUEL PRESSURE RELIEF
Caution: To reduce the risk of fire and personal
injury, it is necessary to relieve the fuel system
pressure before servicing the fuel system
components.
Caution: After relieving the fuel system pressure, a
small amount of fuel may be released when
servicing fuel lines or connections. Reduce the
chance of personal injury by covering the fuel line
fitting with a short towel before disconnecting the
fittings. The towel will absorb any fuel that may leak
out. When the disconnect is completed, place the
towel in an approved container.
1. Remove the fuel filler cap.
2. Remove the fuel pump relay from the underhood relay box.
3. Start the engine and allow it to stall.
4. Crank the engine for about 30 seconds.
5. Disconnect the negative battery cable.
FUEL RAIL ASSEMBLY
Removal Procedure
NOTE:
• Use care when removing the fuel rail assembly in order to prevent damage to the injector al connector
terminal and the injector spray tips.
• Fitting should be capped and holes plugged during servicing to prevent dirt and other contaminants from
entering open lines and passage.
Important: An eight-digit identification number is
stamped on side of the fuel injector. Refer to this
number when you service the fuel rail or when a
replacement part is required.
1. Disconnect 4 injector connectors.
2. Lift side-clip up on the fuel rail.
3. Disconnect fuel pressure regulator hose.
4. Disconnect wiring harness from the bands on the fuel rail.
5. Remove the intake pipe.
6. Loosen flare nut.
A. Lift up the injectors carefully to separate them from intake manifold.
B. Lift up the fuel rail with injectors as assembly. Do not separate the fuel injectors from fuel rail.
C. If an injector become separated from fuel rail, injector backup O-ring and injector retainer clip
must be replaced.
D. Drain residual fuel from fuel rail into an approved container.
7. If removal of fuel pressure regulator is necessary, Refer to Fuel Pressure Regulator Removal
Procedure .

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ISUZU KB P190 2007

ENGINE DRIVEABILITY AND EMISSIONS 6E–271
8. If removal of fuel injector is necessary, Refer to Fuel
Injectors Removal Procedure .
Installation Procedure 1. Install the fuel injectors if necessary. Refer to Fuel Injector Installation Procedure.
2. Install the fuel pressure regulator if necessary. Refer to Fuel Pressure Regulator Installation Procedure .
3. Place the fuel injector rail assembly on the manifold and insert the injectors into each port by pushing
fuel rail.
4. Install two fuel rail retaining bolts. Tighten fuel rail retaining bolt to 19 N·m (1.9kgf·m)
5. Place wiring harness in its place and secure it with two nuts.
6. Connect all connector to each fuel injector.
7. Connect the fuel supply line securely. Do not over tighten. 8. Connect the fuel return line securely. Do not over
tighten.
9. Connect the negative battery cable.
10. Crank the engine until it starts. Cranking the engine may take longer than usual due to trapped air in the
fuel system. Check for leak. If fuel leak is observed,
stop engine immediately. Before correcting fuel
leak, be sure to depressurize system again.

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ISUZU KB P190 2007

6E–274 ENGINE DRIVEABILITY AND EMISSIONS
5. Remove the fuel pressure regulator retaining screw.
6. Remove the fuel pressure regulator from fuel rail.
Installation Procedure 1. Insert the fuel pressure regulator into the fuel rail. 2. Install the fuel pressure regulator retaining bracket
and tighten with a screw.
3. Connect vacuum line onto the fuel pressure regulator.
4. Install the fuel pump relay.
5. Connect the negative battery cable.
6. Crank the engine until it starts. Cranking the engine may take longer than usual due to trapped air in the
fuel line.
7. Tighten the flare nut to 27 - 33 N·m (2.8 - 3.4 kgf·m).

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ISUZU KB P190 2007

ENGINE DRIVEABILITY AND EMISSIONS 6E–277
SPARK PLUG CABLES
The cable contains a synthetic conductor which is easily
damaged. Never stretch or kink the cable. Disconnect
the cable from spark plug and the ignition coil.
The original equipment cables and the ignition coil are
marked to show correct location of the cables. If spark
plug cables or the ignition coil are replaced previously,
before cables are removed from the ignition coil, mark
the cables and the coil so they can be reconnected in
the same position.
Inspection
NOTE: Never puncture the spark plug cable’s insulation
with a needle or the pointed end of a probe into the
cable. An increase in resistance would be created which
would cause the cable to become defective.
1. If the cable has broken or cracked insulation, it must be replaced.
2. If the terminals are corroded or loose, the cable must be replaced.
3. Check that the cable resistance does not exceed specified value.
#1 cylinder: 3.50k Ω - 5.24k Ω
#2 cylinder: 2.89k Ω - 4.33k Ω
#3 cylinder: 2.49k Ω - 3.73k Ω
#4 cylinder: 2.22k Ω - 3.32k Ω
EMISSION CONTROL ; *
**
*
CO ADJUSTER (W/
O CATALYSTIC CONVERTER)
* CO : Carbon monoxide
Location
Under the leht-hand side of the front sheet.
Removal Procedure 1. Remove the left-hand side of the front sheet. Refer to Sec.10 CAB “Front Sheet”.
2. Disconnect the CO adjuster connector.
3. Remove the CO adjuster.
Installation Procedure 1. Connect the CO adjuster connector.
2. Install the left-hand side of the front sheet. Refer to Sec.10 CAB “Front Sheet”.
3. Check and adjust CO concentration.
Checking procedure 1. Operate the engine at normal temperature.
2. Turn all accessories switch OFF.
3. Place the select lever in the “N” range.
4. Start the engine at idle.

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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–2

Visual / Physical Inspection ................................................................................................................................ 28
Intermittent ........................................................................................................................................................... 28
2.3 Engine Misfire without Internal Engine Noises .................................................................................. ............... 29
2.4 Engine Misfire with Abnormal Internal Lower Engine Noises...................................................................... .... 30
2.5 Engine Misfire with Abnormal Valve Train Noise .............................................................................................. 31
2.6 Engine Misfire with Coolant Consumption ........................................................................................................ 31
2.7 Engine Misfire with Excessive Oil Consumption .................................................................................. ............ 31
2.8 Engine Noise on Start-up, but only Lasting a Few Seconds ....................................................................... ..... 31
2.9 Upper Engine Noise, Regardless of Engine Speed........................................................................................... 33
2.10 Lower Engine Noise, Regardless of Engine Speed ................................................................................. ......... 34
2.11 Engine Noise Under Load ................................................................................................................................... 35
2.12 Engine Will Not Crank – Crankshaft Will Not Rotate ............................................................................. ........... 35
2.13 Coolant in Combustion Chamber ....................................................................................................................... 37
Definition .............................................................................................................................................................. 37
2.14 Coolant in Engine Oil.......................................................................................................... ................................. 37
Definition .............................................................................................................................................................. 37
2.15 Engine Compression Test ........................................................................................................ ........................... 38
Preliminary Steps................................................................................................................................................. 38
Engine Cylinder Compression Test ............................................................................................... .................... 38
Test Result Evaluation......................................................................................................................................... 38
2.16 Cylinder Leakage Test .......................................................................................................... ............................... 39
2.17 Engine Oil Consumption Diagnosis ............................................................................................... .................... 39
Definition .............................................................................................................................................................. 39
2.18 Engine Oil Leak Diagnosis ...................................................................................................... ............................ 40
Introduction .......................................................................................................................................................... 40
Locating and Identifying the Leak .............................................................................................. ........................ 40
Visual Inspection ................................................................................................................................................. 40
Powder Method .................................................................................................................. .................................. 40
Black Light and Dye Method ..................................................................................................... .......................... 40
Possible Causes for Engine Oil Leaks ........................................................................................... .................... 41
2.19 Engine Oil Pressure Diagnosis ........................................................................................................................... 42
2.20 Accessory Drive Belt Diagnosis ................................................................................................. ........................ 42
Tension Check ..................................................................................................................................................... 42
Inspect .................................................................................................................................................................. 42
Drive Belt Chirp .................................................................................................................................................... 43
Definition .......................................................................................................................................................... 43
Diagnostic Aids................................................................................................................................................. 43
Test Description ............................................................................................................... ................................ 43
Diagnostic Table............................................................................................................................................... 44
Drive Belt Squeal .............................................................................................................. ................................... 45
Definition .......................................................................................................................................................... 45
Diagnostic Aids................................................................................................................................................. 45
Test Description ............................................................................................................... ................................ 45
Diagnostic Table............................................................................................................................................... 46
Drive Belt Whine ............................................................................................................... ................................... 46
Definition .......................................................................................................................................................... 46
Diagnostic Aids................................................................................................................................................. 46
Test Description ............................................................................................................... ................................ 46
Diagnostic Table............................................................................................................................................... 47
Drive Belt Rumble .............................................................................................................. .................................. 47
Definition .......................................................................................................................................................... 47
Diagnostic Aids................................................................................................................................................. 48
Test Description ............................................................................................................... ................................ 48
Diagnostic Table............................................................................................................................................... 48
Drive Belt Vibration........................................................................................................... ................................... 49
Definition .......................................................................................................................................................... 49
Diagnostic Aids................................................................................................................................................. 49
Test Description ............................................................................................................... ................................ 49
Diagnostic Table............................................................................................................................................... 50
Drive Belt Falls Off ........................................................................................................... .................................... 50

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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–22

Crankshaft
The crankshaft is a forged steel design with four main bearings. The number three main bearing controls crankshaft
thrust. A crankshaft position reluctor wheel is pressed onto the rear of the crankshaft, in front of the rear main journal.
The crankshaft is internally balanced with an integral oil pump drive machined into the nose in front of the front main
journal.
Pistons, Pins and Connecting Rods
The piston assembly (1) is fitted with two low tension
compression rings and one multi-piece oil control ring. The
top compression ring is plasma sprayed, while the second
compression ring is cast iron Napier.
The oil control ring incorporates a steel expander and two
chrome plated steel rails.
The connecting rods are sinter forged steel and have full
floating piston pins. The piston pins are a slip-fit type, into
the bronze bushed connecting rods. Round wire retainers
are used to retain the piston pin into the piston.
The cast aluminium pistons incorporate a polymer coated
skirt to reduce friction.
Figure 6A1 – 17
Camshaft Drive System
Three timing chains are fitted:
• primary (1),
• right-hand secondary (2), and
• left-hand secondary (3), refer to Figure 6A1 – 18 for the HFV6 engine.
The primary timing chain connects the crankshaft sprocket (4) with the left-hand and right-hand intermediate drive shaft
sprockets (5).
Each oil pressure fed intermediate sprocket drives the secondary timing chains, which subsequently drive the respective
cylinder head camshaft position actuators (6).
Two stationary timing chain guides (7) and movable timing chain shoes (8) control secondary timing chain backlash.
Each secondary timing chain shoe is under tension from an oil pressure hydraulically operated tensioner (9). To control
backlash on the primary chain, two stationary timing chain guides (10) and an oil pressure hydraulically actuated
tensioner with built in shoe (11) are fitted.
The tensioners minimise timing chain noise and provide accurate valve action by keeping slack out of the timing chains,
while continuously adjusting for timing chain wear. The tensioners incorporate a plunger that adjusts outward with wear,
minimising backlash. The tensioners are equipped with oiling jets to spray oil onto the timing components during engine
operation. Each tensioner is sealed to the head or block using a rubber coated steel gasket. The gasket traps an
adequate oil reserve to ensure quiet start-up.

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Engine Mechanical – V6 Page 6A1–24

1.5 Engine Lubrication System
Lubrication Description
A structural diecast aluminium oil pan is fitted that incorporates an oil suction pipe, an oil deflector and an oil level sensor.
The oil suction pipe is bolted into the oil pan and seals to the bottom of the cylinder block with a gasket. The oil deflector
is bolted to the upper portion of the oil pan and ensures oil supply is maintained under all conditions. The oil level sensor
is mounted through the bottom of the oil pan.
A crankshaft driven gerotor oil pump is mounted to the front of the cylinder block. The pump, which incorporates an
internal pressure-relief valve, draws oil from the oil suction tube through the lower passage in the cylinder block. Oil is
then directed through an upper passage to the left-hand side of the cylinder block where the oil filter adapter is mounted.
The oil filter adapter incorporates a top-access, cartridge style oil filter. The filter is accessed through a screw-on cap tha t
incorporates an oil bypass valve. The oil filter adapter housing incorporates a drain back control valve and a threaded oil
pressure sender. Oil flows through a lower passage within the oil filter adapter and through the oil filter cartridge. Filtered
oil travels back through the upper passage of the adapter and into the engine block.
Oil is then directed up and across the front of the cylinder block, through several drilled passages. These front passages
feed oil to each cylinder head, the passage for the main bearings and piston oil jets, the right-hand and left-hand
secondary idler sprockets and to the primary timing chain tensioner.
Each cylinder head passage directs oil into oiling circuits for the stationary hydraulic lash adjusters (SHLAs) and the
camshaft bearing journals. An additional passage in the cylinder head also directs oil to the secondary timing chain
tensioner.
The oil passage that supplies oil to the main bearings also supplies oil to pressure actuated piston cooling oil jets. Each
oil jet is mounted between opposing cylinder bores and directs oil to the two bores to provide extra cooling and control
piston temperatures.
From the front passages, oil is directed to the front of the block where the right-hand and left-hand intermediate drive
shaft sprockets and the primary timing chain tensioner are mounted. Each camshaft timing chain tensioner relies on a
gasket to maintain an oil reserve after the engine is turned off. All camshaft timing chain tensioners incorporate a small
oil jet to supply an oil spray onto the camshaft timing chain components.
Oil returns to the oil pan, either through the camshaft timing chain area or through the drain back passages on the
outboard walls of the cylinder heads and cylinder block.
1.6 Service Notes
Cleanliness and Care
Throughout this Section, correct cleaning and protection of machined surfaces and friction areas is a part of the repair
procedure. This is considered standard workshop practice, even if not specifically stated.
W hen any internal engine part is serviced, care and cleanliness is extremely important.
W hen components are removed for service, they should be marked, organised or retained in a specific order for
reassembly.
At the time of installation, components should be installed in the same location and with the same mating surface as
when removed.
Any engine is a combination of many machined, honed, polished and lapped surfaces with tolerances that are measured
in thousandths of a millimetre. These surfaces should be covered or protected to avoid component damage.
A liberal coating of clean engine oil should be applied to friction areas during assembly, as the lubrication will protect and
lubricate friction surfaces during the initial engine start-up.
Replacing Engine Gaskets
Re-Using Gaskets and Applying Sealants
• do not reuse any gasket unless specified,
• gaskets that can be reused will be identified in the service procedure, and
• do not apply sealant to any gasket or sealing surface unless specified in the service information.
Separating Components
• Use a rubber mallet to separate components.
• Bump the part sideways to loosen the components.
• Bumping should be done at bends or reinforced areas to prevent distortion of parts.
Cleaning Gasket Surfaces
• W here required, remove all gasket and sealing material from the part using a plastic or wood scraper.
• Care must be used to avoid gouging or scraping the sealing surfaces.

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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–28

2 Diagnosis
2.1 Engine Diagnosis
Begin engine mechanical system diagnosis by reviewing the disassembled views provided in 1.2 Engine Components
and 1.4 Engine Construction. Reviewing the description and operation information provided will assist in determining
whether the condition described by the customer is a fault or normal engine operation.
2.2 Symptoms
Strategy Based Diagnosis
1 Review the system operations to familiarise yourself with the system functions, refer to 1 General Information and 6C1-1 Engine Management General Information.
2 Perform an engine management Diagnostic System Check, refer to 6C1-2 Engine Management – V6 – Diagnostics.
All diagnosis on a vehicle should follow a logical process. Strategy based diagnosis is a uniform approach for repairing
all vehicle systems. The strategy based diagnostic flow chart may always be used to resolve a system problem. The
diagnostic flow chart is the place to start when repairs are required. For a detailed explanation of strategy based
diagnosis and the flow chart, refer to 6C1-2 Engine Management – V6 – Diagnostics.
Visual / Physical Inspection
1 Inspect the vehicle for aftermarket accessories which may adversely affect engine operation.
2 Inspect the easily accessible or visible system components for obvious signs of damage or conditions that may cause the symptom.
3 Check the engine lubrication system for the following:
• correct oil level,
• correct lubricant viscosity,
• correct oil filter application, and
• contaminated or burnt oil.
4 Confirm the exact operating conditions under which the fault occurs. Note factors such as:
• engine speed (r.p.m.),
• ambient temperature,
• engine temperature,
• engine warm-up time, and
• vehicle road speed.
5 Compare the engine sounds, if applicable, to a known good engine, and ensure you are not trying to diagnose a normal operating condition.
Intermittent
For intermittent faults, test the vehicle under the same conditions the customer reported in order to confirm whether the
system is operating correctly.

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Engine Mechanical – V6 Page 6A1–31

2.5 Engine Misfire with Abnormal Valve
Train Noise
Cause Correction
W orn or loose stationary hydraulic lash adjusters (SHLA)
and/or valve rocker arms.
The SHLAs, rocker arm and roller bearings should be intact
and in the correct position. Replace the SHLAs and/or rocker arms as required, refer to
3.21 Stationary Hydraulic Lash Adjuster or 3.20
Rocker Arm.
Stuck valves.
Carbon build up on the valve stems can result in the valves
not closing correctly. Repair or replace as required, refer to 3.22 Cylinder Head
Assembly.
Excessively worn or misaligned timing chain/s. Replace the timing chain/s and components as required,
refer to 3.16 Timing Chains, Tensioners, Shoes and
Guides.
W orn camshaft lobes. Replace the camshaft/s and SHLAs as required, refer to
3.19 Camshaft or 3.21 Stationary Hydraulic Lash
Adjuster.
Sticking camshaft lash adjusters. Replace the lash adjusters as required, refer to 3.21
Stationary Hydraulic Lash Adjuster.
2.6 Engine Misfire with Coolant
Consumption
Cause Correction
Faulty cylinder head gasket and/or cracking or other
damage to the cylinder heads and cylinder block coolant
passages.
Coolant consumption may or may not cause the engine to
overheat. 1 Inspect the spark plugs for coolant saturation, refer to
6C1-3 Engine Management – V6 – Service
Operations.
2 Inspect the cylinder heads, cylinder block and/or head gaskets, refer to 3.22 Cylinder Head Assembly and/or
4.7 Cylinder Block.
3 Repair or replace components as required.
2.7 Engine Misfire with Excessive Oil Consumption
Cause Correction
W orn valves, valve guides and/or valve stem oil seals. 1 Inspect the spark plugs for coolant saturation, refer to 6C1-3 Engine Management – V6 – Service
Operations.
2 Repair or replace components as required, refer to 3.22 Cylinder Head Assembly.
W orn or broken piston rings.
Oil consumption may or may not cause an actual misfire. 1 Inspect the spark plugs for oil deposits, refer to 6C1-3
Engine Management – V6 – Service Operations.
2 Check the cylinders for a loss of compression, refer to 2.15 Engine Compression Test.
3 Perform compression testing to identify the cause of low compression.
4 Repair or replace components as required.
2.8 Engine Noise on Start-up, but only Lasting a Few Seconds
NOTE
A cold piston knock, which disappears in
approximately 1.5 minutes from start up, should
be considered acceptable. A cold engine knock
usually disappears when the specific cylinder’s

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ISUZU KB P190 2007

Engine Mechanical – V6 Page 6A1–33

2.9 Upper Engine Noise, Regardless of
Engine Speed
NOTE
A cold piston knock, which disappears in
approximately 1.5 minutes from start up, should
be considered acceptable. A cold engine knock
usually disappears when the specific cylinder’s
secondary ignition circuit is grounded out during
diagnosis.
A light rattle/tapping noise may indicate a valve train/upper engine concern, while a low rumble/knocking may indicate a
crankshaft, piston or lower engine concern.
Cause Correction
Low oil pressure. 1 Perform an oil pressure test, refer to 2.19
Engine Oil Pressure Diagnosis.
2 Repair or replace the engine oil pump as required, refer to 3.17 Oil Pump Assembly.
W orn or loose stationary hydraulic lash adjusters (SHLA)
and/or valve rocker arms.
The SHLAs, rocker arm and roller bearings should be intact
and in the correct position. 1 Clean, inspect and replace the camshaft lash
adjusters as required, refer to 3.21 Stationary
Hydraulic Lash Adjuster.
2 Replace the SHLAs and/or rocker arms as required, refer to 3.21 Stationary Hydraulic Lash Adjuster or
3.20 Rocker Arm.
Incorrect lubrication to the stationary hydraulic lash
adjusters and valve rocker arm. Inspect the following components and repair or replace as
required:
• valve rocker arms, refer to 3.20 Rocker Arm.
• stationary hydraulic lash adjusters, refer to 3.21
Stationary Hydraulic Lash Adjuster.
• oil filter by-pass valve, refer to 3.3 Oil Filter
Adaptor.
• oil pump and suction pipe, refer to 3.17 Oil Pump
Assembly.
• cylinder head oil galleries, refer to 3.22 Cylinder Head
Assembly.
• cylinder block oil galleries, refer to 4.7 Cylinder
Block.
Broken Valve Spring. Replace the valve spring, refer to 3.22 Cylinder Head
Assembly.
Stretched or broken timing chain/s and/or damaged timing
chain sprocket teeth. Replace the timing chains or sprockets as required, refer to
3.16 Timing Chains, Tensioners, Shoes and Guides.
W orn or faulty timing chain tensioner or guide. Replace the timing chains or sprockets as required, refer to
3.16 Timing Chains, Tensioners, Shoes and Guides.
W orn camshaft lobes. Replace the camshaft/s and SHLAs as required, refer to
3.19 Camshaft or 3.21 Stationary Hydraulic Lash
Adjuster.
W orn valve guides and/or valve stems. Inspect and repair or replace valves and valve guides as
required, refer to 3.22 Cylinder Head Assembly.
Stuck valves.
Carbon on the valve stem or valve seat may cause the
valve to stay open. Inspect and repair or replace valves and valve guides as
required, refer to 3.22 Cylinder Head Assembly.

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