6E–236 ENGINE DRIVEABILITY AND EMISSIONS
HARD START SYMPTOM
DEFINITIONS: Engine cranks, but does not start for a long time. Does eventually start, of may start and then
immediately stall.
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 visually/physical check performed? —Go to Step 4Go to
Visual /
physical Check.
4 1. Visually/physically inspect for the following conditions:
• Restriction of air intake system. Check for a restricted air filter element, or foreign objects
blocking the air intake system
• Check for objects blocking the IAC passage or throttle bore, excessive deposits in the throttle
bore and on the throttle plate
• Check for a condition that causes a large vacuum leak, such as an incorrectly installed or
faulty crankcase ventilation hose/brake booster
hose.
Was a problem found? — Verify repair Go to Step 5
5 1. Using a Tech 2, display the IAC value. 2. Check for a faulty, plugged, or sticking IACoperation.
Was the problem found? — Verify repair Go to Step 6
6 Check engine coolant temperature (ECT) sensor for shift in value.
1. After 8 hours with hood up and the engine not running, connect the Tech 2.
2. Ignition On, engine not running.
3. Using Tech 2, compare Engine Coolant Temperature to Intake Air Temperature.
Are ECT and IAT within the specified value of each
other? ± 5°C Go to Step 8Go to Step 7
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ISUZU KB P190 2007
ENGINE DRIVEABILITY AND EMISSIONS 6E–237
7 1. Using a Tech 2, display the engine coolanttemperature and note the value.
2. Check the resistance of the engine coolant temperature sensor.
Is the actual resistance near the resistance value in
the chart for the temperature that was noted?
—Go to Step 8Replace the
ECT sensor. Verify repair
8 1. Using a Tech 2, display the MAP sensor value in comparison with atmosphere temperature.
2. Check for a faulty, plugged, or incorrectly installed MAP sensor.
Was the problem found? — Verify repair Go to Step 9
9 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 10
10 Check for proper ignition voltage output with a spark tester.
Was the problem found? — Verify repair Go to Step 11
11 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 12
12 Check for a loose ignition control module ground. Was a problem found? — Verify repair Go to Step 13
13 1. Check the ignition coil secondary resistance. 2. Replace the coil if it is greater than the specifiedresistance.
Did the coil require replacement? 2.5kΩ Verify repair Go to Step 14
Step
Action Value(s) Yes No
Temperature (°C) Resistance (Ω) (Approximately)
-20 26740
0 9120
20 3500
40 1464
60 664
80 333
100 175
120 102
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ISUZU KB P190 2007
6E–240 ENGINE DRIVEABILITY AND EMISSIONS
7 1. Using a Tech 2, display the engine coolanttemperature and note the value.
2. Check the resistance of the engine coolant temperature sensor.
Is the actual resistance near the resistance value in
the chart for the temperature that was noted?
—Go to Step 8Replace the
ECT sensor. Verify repair
8 1. Using a Tech 2, display the MAP sensor value in comparison with atmosphere temperature.
2. Check for a faulty, plugged, or incorrectly installed MAP sensor.
Was the problem found? — Verify repair Go to Step 9
9 Using Tech 2, monitor throttle position with the engine idling.
Is the throttle position at the specified value and
steady?
0% Go to Step 10Refer to
Diagnostic
Trouble Code P0123 for further
diagnosis
10 Check for proper ignition voltage output with the spark tester.
Was a problem found? — Verify repair Go to Step 11
11 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 12
12 Check for a loose ignition control module ground. Was a problem found? — Verify repair Go to Step 13
13 Check items that can cause the engine to run rich. Refer to DTC P1167 “Fuel Supply System Rich During
Deceleration Fuel Cut Off”.
Was a problem found? — Verify repair Go to Step 14
14 Check items that can cause the engine to run lean. Refer to DTC P1171 “Fuel Supply System Lean
During Power Enrichment”.
Was a problem found? — Verify repair Go to Step 15
15 Check the injector connectors, if any of the injectors are connected any incorrect cylinder, correct as
necessary.
Was a problem found? — Verify repair Go to Step 16
16 1. Check for faulty engine mounts. 2. If a problem is found, repair as necessary.
Was a problem found? — Verify repair Go to Step 17
Step
Action Value(s) Yes No
Temperature (°C) Resistance (Ω) (Approximately)
-20 26740
0 9120
20 3500
40 1464
60 664
80 333
100 175
120 102
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ISUZU KB P190 2007
6E–254 ENGINE DRIVEABILITY AND EMISSIONS
DETONATION/SPARK KNOCK SYMPTOM
DEFINITIONS: A mild to severe ping, usually worse under acceleration. The engine makes a sharp metallic knocking
sound that changes with throttle opening. Prolonged detonation may lead to complete engine tailure.
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 1. If Tech 2 readings are normal (refer to Typical Scan Data Values) and there are no engine
mechanical faults, fill the fuel tank with a known
quality gasoline.
2. Re-evaluate the vehicle performance.
Is detonation present? — Go to Step 5Verify repair
5 1. Check for obvious overheating problems: • Low engine coolant
• Restricted air flow to radiator
• Incorrect coolant solution
2. If a problem is found, repair as necessary.
Was a problem found? — Verify repair Go to Step 6
6 Check the fuel pressure. Refer to 6E-108 page “ Fuel
System Diagnosis” .
Was a problem found? — Verify repair Go to Step 7
7 1. Using a Tech 2, display the MAP sensor value in comparison with atmosphere temperature.
2. Check for a faulty, plugged, or incorrectly installed MAP sensor.
Was the problem found? — Verify repair Go to Step 8
8 1. Using a Tech 2, display the ECT sensor and IAT sensor value and warm up condition compared
with the typical data.
2. Check the specified value or wire.
Was the problem found? — Verify repair Go to Step 9
9 Observe the throttle position display on the Tech 2 while slowly increasing throttle pedal.
Does the throttle position increase steady with
increasing smoothly?
—Go to Step 10Refer to
Diagnostic
Trouble Code P0123 for further
diagnosis
10 Check the knock sensor wire, shield wire, or installation condition.
Was a problem found? — Verify repair Go to Step 11
11 Check items that can cause the engine to run lean. Refer to DTC P1171 “Fuel Supply System Lean
During Power Enrichment”.
Was a problem found? — Verify repair Go to Step 12
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ISUZU KB P190 2007
6E–256 ENGINE DRIVEABILITY AND EMISSIONS
POOR FUEL ECONOMY SYMPTOM
DEFINITIONS: Fuel economy, as measured by an actual road test, is noticeably lower than expected. Also, economy
is noticeably lower than it was on this vehicle at one time, as previously shown by an actual road test.
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 owner’s driving habits. • Is the A/C On full time (defroster mode On)?
• Are tires at the correct pressure?
• Are excessively heavy loads being carried?
• Is acceleration too much, too often? — Go to Step 5Go to Step 6
5 Review the items in Step 4 with the customer and advise as necessary.
Is the action complete? — System OK —
6 Visually/physically check: Vacuum hoses for splits, kinks, and improper connections and routing as
shown on the “Emission Control System Schematics”.
Was a problem found? — Verify repair Go to Step 7
7 Check for low engine coolant level. Was a problem found? — Verify repair Go to Step 8
8 Check for incorrect or faulty engine thermostat. Refer to Engine Cooling .
Was a problem found? — Verify repair Go to Step 9
9 Remove and check the air filter element for dirt or for restrictions.
Was a problem found? — Verify repair Go to Step 10
10 1. Using a Tech 2, display the MAP sensor value in comparison with atmosphere temperature.
2. Check for a faulty, plugged, or incorrectly installed MAP sensor.
Was the problem found? — Verify repair Go to Step 11
11 1. Using a Tech 2, display the ECT sensor and IAT sensor value and warm up condition compared
with the typical data.
2. Check the specified value or wire.
Was the problem found? — Verify repair Go to Step 12
12 Check the knock sensor wire, shield wire, or installation condition.
Was a problem found? — Verify repair Go to Step 13
13 Check the fuel pressure. Refer to 6E-108 page “Fuel
System Diagnosis
” .
Was a problem found? — Verify repair Go to Step 14
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ISUZU KB P190 2007
ENGINE DRIVEABILITY AND EMISSIONS 6E–265
ENGINE COOLANT TEMPERATURE (ECT)
SENSOR
Location
Installed to the thermostat housing.
Removal Procedure 1. Disconnect the negative battery cable.
2. Drain enough engine coolant so that the coolant level will be below the ECT sensor.
3. Disconnect connector from the ECT sensor.
4. Loosen and remove the ECT sensor from the thermostat housing.
NOTE: Cool down the engine before above procedures
are carried out.
Installation Procedure
1. Apply sealer to threads of screw at the ECT sensor.
2. Tighten the ECT sensor with specified tightening torque.
Tightening Torque
• Bolt: 13N·m (1.3kgf·m)
3. Connect a ECT sensor connector to the ECT sensor.
4. Fill the engine coolant.
5. Connect the negative battery cable.
NOTE: Verify any DTCs (diagnosis Trouble Code) are
not stored after replacement.
Verify no engine coolant leaking from the sensor
threads after replacement.
INTAKE AIR TEMPERATURE (IAT) SENSOR
Location
Installed to the intake duct housing.
Removal Procedure 1. Disconnect the negative battery cable.
2. Disconnect a IAT sensor connector from the IAT sensor.
3. Remove the IAT sensor from the intake duct.
Installation Procedure 1. Install the IAT sensor into intake air duct.
2. Connect a IAT sensor connector to the IAT sensor.
3. Connect the negative battery cable.
NOTE: Verify any DTCs (diagnosis Trouble Code) are
not stored after replacement.
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ISUZU KB P190 2007
Engine Mechanical – V6 Page 6A1–15
Cylinder Head Assembly
Figure 6A1 – 7
Legend
1 Cylinder Head, Left-hand
2 Cylinder Head, Right-hand
3 Cylinder Head Gasket, Left-hand
4 Cylinder Head Gasket, Right-hand
5 Cylinder Head Bolt
6 Cylinder Head Front Bolt
7 Cylinder Head Coolant Hole Threaded Plug
8 Spark Plug Sleeve
9 Cylinder Head Oil Gallery Expansion Plug
10 Exhaust Valve
11 Intake Valve
12 Valve Rocker Arm Assembly
13 Hydraulic Valve Lash Adjuster Assembly
14 Valve Stem Oil Seal 15 Valve Spring
16 Valve Spring Cap
17 Valve Stem Key
18 Cylinder Head Camshaft Front Thrust Bearing Cap
19 Camshaft Oil Seal Ring
20 Exhaust Camshaft
21 Intake Camshaft, Left-hand (bank 2)
22 Intake Camshaft, Right-hand (bank 1)
23 Exhaust Camshaft, Right-hand (bank 1)
24 Cylinder Head Camshaft Cap – Intermediate
25 Cylinder Head Camshaft Cap Bolt
26 Cylinder Head Oil Galley Check Valve
27 Engine Coolant Temperature Sensor
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ISUZU KB P190 2007
Engine Mechanical – V6 Page 6A1–37
2.13 Coolant in Combustion Chamber
Definition
Excessive white smoke and/or coolant type odour emitted from the exhaust pipe may indicate coolant in the combustion
chamber. Low coolant levels, an inoperative engine cooling fan or a faulty thermostat may lead to an over-temperature
condition which may cause internal engine component damage. A slower than normal cranking speed may indicate
coolant entering the combustion chamber.
1 Remove the spark plugs and inspect for spark plugs saturated by coolant and coolant in the cylinder bore.
2 Inspect by performing a cylinder leakage test, refer to 2.16 Cylinder Leakage Test. During this test, excessive air bubbles in the coolant may indicate a faulty head gasket, cracked cylinder head or cracked cylinder
block.
3 Inspect by performing a cylinder compression test. Two cylinders side-by-side on the cylinder block, with low compression, may indicate a failed cylinder head gasket, refer to 2.15 Engine Compression Test.
Cause Correction
Cracked intake manifold or faulty gasket. Replace components as required, refer to 3.10
Intake Manifold Assembly – Complete.
Faulty cylinder head gasket. Replace the cylinder head gasket, refer to 3.22
Cylinder Head Assembly.
W arped cylinder head. Repair or replace the cylinder heads as required, refer to
3.22 Cylinder Head Assembly.
Cracked cylinder liner or block Repair or replace the cylinder block and components as
required, refer to 4.7 Cylinder Block.
Cylinder head or cylinder block porosity. Repair or replace the cylinder block or cylinder heads as
required, refer to 4.7 Cylinder Block or 3.22
Cylinder Head Assembly.
2.14 Coolant in Engine Oil
Definition
Foamy or discoloured oil or an engine oil overfill condition may indicate coolant entering the engine crankcase. Low
coolant levels, an inoperative engine cooling fan or a faulty thermostat may lead to an over-temperature condition which
may result in engine component damage. Contaminated engine oil and oil filters must be replaced.
1 Inspect the oil for excessive foaming or an overfill condition. Oil diluted by coolant may not correctly lubricate the crankshaft bearings, resulting in component damage, refer to 2.10 Lower Engine Noise, Regardless of Engine
Speed.
2 Perform a cylinder leakage test, refer to 2.16 Cylinder Leakage Test. During this procedure, excessive air bubbles in the engine coolant may indicate a faulty gasket or damaged component.
3 Perform a cylinder compression test. Two cylinders side-by-side on the cylinder block, with low compression, may indicate a failed cylinder head gasket, refer to 2.15 Engine Compression Test.
Cause Correction
Faulty cylinder head gasket. Replace the cylinder head gasket, refer to 3.22
Cylinder Head Assembly.
W arped cylinder head. Repair or replace the cylinder heads as required, refer to
3.22 Cylinder Head Assembly.
Cracked cylinder liner or block Repair or replace the cylinder block and components as
required, refer to 4.7 Cylinder Block.
Cylinder head, cylinder block or intake manifold porosity. Repair or replace the cylinder block, cylinder heads or intake manifold components as required, refer to 4.7
Cylinder Block, 3.22 Cylinder Head
Assembly or 3.10 Intake Manifold Assembly – Complete.
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ISUZU KB P190 2007