6E–262 ENGINE DRIVEABILITY AND EMISSIONS
BACKFIRE SYMPTOM
DEFINITIONS: Fuel ignites in the intake manifold, or in the exhaust system, making a loud popping noise.
Step Action Value(s) Yes No
1 Was the “ On-Board Diagnostic (OBD) System Check ”
performed? — Go to Step 2Go to
OBD
System Check
2 1. Perform a bulletin search. 2. If a bulletin that addresses the symptom is found,correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom? — Verify repair Go to Step 3
3 Was a visual/physical check performed? —Go to Step 4Go to
Visual /
physical Check .
4 Check for proper ignition voltage output with the spark tester.
Was a problem found? — Verify repair Go to Step 5
5 1. Remove the spark plugs and check for gas or oil fouling cracks, wear, improper gap, burned
electrodes, heavy deposits, or improper heat
range.
2. If spark plugs are fouled, the cause of fouling must be determined before replacing the spark plugs.
Was a problem found? — Verify repair Go to Step 6
6 Visually/physically inspect all spark plug high-tension cables. Check for the following conditions:
• Verify that the resistance of all spark plug high- tension cables are less than the specified value.
• Verify that the all spark plug high-tension cables are correctly fitted to eliminate cross-fitting.
• Verify that the all spark plug high-tension cables are not arcing to ground.
Spraying the spark plug high-tension cables with a
light mist of water may help locate an intermittent
problem.
Was a problem found? #1 cyl. 4.4k
Ω
#2 cyl. 3.6k Ω
#3 cyl. 3.1k Ω
#4 cyl. 2.8k ΩVerify repair Go to Step 7
7 Check the fuel pressure. Refer to 6E-108 page “Fuel
System Diagnosis” .
Was a problem found? — Verify repair Go to Step 8
8 Check for an intermittent ignition system malfunction: • Intermittent CKP 58X signal
• Intermittent ignition feed circuit or sensor ground circuit to the crankshaft position sensor.
Was a problem found? — Verify repair Go to Step 9
9 Refer to 6E-108 page “Fuel System Diagnosis ” to
determine if there is a problem with fuel delivery.
Was a problem found? — Verify repair Go to Step 10
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ISUZU KB P190 2007
6E–272 ENGINE DRIVEABILITY AND EMISSIONS
FUEL INJECTOR
Removal Procedure
NOTE: If the fuel injectors are leaking, the engine oil
may be contaminated with fuel. Check the oil for signs
of contamination and change the oil and filter if
necessary.
NOTE: Use care in removing the fuel injector in order to
prevent damage to the fuel injector al connector pins or
fuel injector nozzles. The fuel injector is an al
component and should not be immersed in any type of
cleaner as this may damage the fuel injector.
Important: Fuel injectors are serviced as complete
assembly only.
1. Disconnect the negative battery cable.
2. Disconnect al connector from fuel injector.
3. Remove the fuel rail. Refer to Fuel Rail Removal
Procedure .
4. Remove the fuel injector retainer clip.
5. Remove the fuel injector assembly from fuel rail.
6. Remove O-ring from the fuel injector.
7. Remove O-ring backup from fuel injector. Inspection
1. Inspect O-ring for crack, damage or leaks.
2. Replace worn or damaged O-ring.
3. Lubricate the new O-rings with engine oil before installation.
Installation Procedure
1. Lubricate the new O-ring with engine oil.
2. Install the O-ring backup on the fuel injector.
3. Install new O-ring on the fuel injector.
4. Install all four injector on the fuel rail.
5. Use new injector retainer clip to retain the injetor to the fuel rail.
6. Coat the end of the fuel injector with engine oil.
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ISUZU KB P190 2007
ENGINE DRIVEABILITY AND EMISSIONS 6E–275
IGNITION COIL
Location
Back of the engine right-hand side.
Removal Procedure 1. Disconnect the negative battery cable.
2. Disconnect the ignition coil connector.
3. Disconnect four spark plug cables from the ignition coil.
4. Loosen three bolts and remove ignition coil from the bracket.
Installation Procedure 1. Tighten the ignition coil by three bolts.
2. Connect four spark plug cables to the ignition coil.
3. Connect a ignition coil connector to the ignition coil.
4. Connect the negative battery cable.
NOTE: Verify any DTCs (diagnosis Trouble Code) are
not stored after replacement.
Verify proper connection of spark plug cables for each
cylinders.
SPARK PLUGS
Location
Installed on the left-hand side of cylinder head.
Removal Procedure 1. Disconnect the negative battery cable
2. Remove the spark plug cable.
3. Remove the spark plug.
Inspection 1. Check the insulator for cracks. Replace the spark plug if cracks are present.
2. Check the electrode condition and replace the spark plug if necessary.
If the spark plug electrodes and insulators are fouled
with carbon or oil, the engine will not operate efficiently.
There are a number of possible causes:
• Fuel mixture is too rich.
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ISUZU KB P190 2007
6E–276 ENGINE DRIVEABILITY AND EMISSIONS
• Oil in the combustion chamber.
• The spark plug gap is not set correctly.
If spark plug fouling is excessive, check the fuel and al
system for possible causes of trouble. If fuel and al
system are normal, install spark plugs of a higher heat
range which have the same physical dimensions as the
original equipment spark plugs.
The following symptoms are characteristics of spark
plugs that are running too hot:
• Fuel mixture is too lean.
• Heat range is incorrect.
If vehicle usage does not conform to normal driving
conditions, a more suitable spark plug may be
substituted.
If fuel and al system are normal, in most cases of this
sort, the problem can be corrected by using a colder
type spark plug with the same physical dimensions as
the original equipment spark plug.
3. Check the gaskets for damage and replace if necessary.
4. Measure the spark plug gap. The specification is 1.0 to 1.1mm (0.039 to 0.043").
5. Adjust the spark gap by bending the grounded electrode. Installation
1. Tighten the spark plug to the 25N·m (2.5kgf·m).
2. Push the spark plug cable in until it snaps in.
Installation Procedure 1. Install the spark plug to the cylinder head.
2. Tighten the spark plug with specified tightening torque.
Tightening Torque
• Bolt: 25N·m (2.5kgf·m) 3. Connect the spark plug cable to the spark plug.
4. Connect the negative battery cable.
NOTE: Verify any DTCs (diagnosis Trouble Code) are
not stored after replacement.
Verify proper connection of spark plug cables for each
cylinders.
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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
6G-2 ENGINE LUBRICATION
General Description
Legend
1 Oil Strainer
2 Oil Pump
3 Relief Valve
4 Oil Filter
5 Safety Valve
6 Oil Gallery
7 Crankshaft Bearing
8 Crankshaft 9 Connecting Rod Bearing
10 Connecting Rod
11 Piston
12 Oil Gallery; Cylinder Head
13 Camshaft
14 Camshaft Journal
15 HLV
16 Check relief valve
17 Oil Pan
A gear-type oil pump is directly driven by the crankshaft and
draws oil from the oil pan, via the suction pipe. If then passes
the pressured oil through a full-flow disposable oil filter, to the
main oil gallery in the cylinder Block. An oil pump pressure
relief valve and oil filter bypass valve are incorporated in the
system.
From the main oil gallery in the cylinder block, the cylinder
head and crankshaft main bearings are supplied with oil.
The camshaft bearings and hydraulic tappets are supplied
through the main feed galleries in the cylinder head. Vent
valves allow air to be expelled from the oil galleries in the
cylinder head. The balance shaft journals are directly fed from
the crankshaft main bearings. The connecting rod bearings are
fed via passages in the crankshaft. The oil returns to the oil
pan via passages in the cylinder block.
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ENGINE LUBRICATION 6G-5
Inspection and Repair
CAUTION: Make necessary correction or parts
replacement if wear, damage or any other abnormal
conditions are found through inspection.
Body and Gears
The pump assembly must be replaced if one or more of the
conditions below is discovered during inspection:
Indentation of gear pair - Use feeler strip and straight edge.
Dimension: 0.03 mm to 0.10 mm
(0.0012 to 0.0039 in)
Oil Strainer
Check the oil strainer for cracking and scoring. If cracking and
scoring are found, the oil strainer must be replaced.
Reassembly
1. Install oil pressure switch to the oil pump.
Torque: 40 N ⋅
⋅⋅
⋅
m (4.1 kgf ⋅
⋅⋅
⋅
m)
2. Install the oil pump with the sleeve and the gasket.
Torque: 6 N ⋅
⋅⋅
⋅
m (0.6 kgf ⋅
⋅⋅
⋅
m)
3. Install oil strainer.
Torque: 8 N ⋅
⋅⋅
⋅
m (0.8 kgf ⋅
⋅⋅
⋅
m)
4. Install the oil pan.
Tighten the bolts:
15 N ⋅
⋅⋅
⋅
m (1.5 kgf ⋅
⋅⋅
⋅
m)
5. Install crankshaft timing pulley.
Tighten the bolts:
20 N ⋅
⋅⋅
⋅
m (2.0 kgf ⋅
⋅⋅
⋅
m)
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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