2007 ISUZU KB P190 engine

ENGINE DRIVEABILITY AND EMISSIONS 6E–235
22 Perform the procedure in Fuel System Pressure Test(Refer to 6E-108 “Fuel System Diagnosis ”) to
determine if there is a problem with fuel delivery.
Was a problem found? — Verify repair Go to Step 23
23 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 24
24 Check for the following engine mechanical problems (refer to Engine Mechanical ):
• Low compression
• Leaking cylinder head gaskets
• Worn camshaft
• Camshaft drive belt slipped or stripped
Was a problem found? — Verify repair Go to Step 25
25 1. Review all diagnostic procedures within this table. 2. If all procedures have been completed and nomalfunctions have been found, review/inspect the
following:
• Visual/physical inspection
• Tech 2 data
• All electrical connections within a suspected circuit and/or system
Was a problem found? — Verify repair Go to Step 26
26 Is the ECM programmed with the latest software release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved? — Verify repair Go to Step 27
27 Replace the ECM. Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure. — Verify Repair —
Step
Action Value(s) Yes No

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ISUZU KB P190 2007

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–238 ENGINE DRIVEABILITY AND EMISSIONS
14 Drain sample fuel, visual inspection.Any suspecion about the fuel, such as discoloration,
particle, contamination, water, unusual smell, then
drain the fuel from fuel tank.
Replace the fuel from know vehicle source.
If any suspicion of alcohol contamination, completely
drain the fuel, replace by fuel from known vehicle
source. — Verify repair Go to Step 15
15 Perform the procedure in Fuel System Pressure Test (Refer to 6E-108 “Fuel System Diagnosis ”) to
determine if there is a problem with fuel delivery.
Was a problem found? — Verify repair Go to Step 16
16 1. Check the injector connectors. 2. If any of the connectors are connected at animproper cylinder, connect as necessary.
Was a problem found? — Verify repair Go to Step 17
17 Check for the following engine mechanical problems (refer to Engine Mechanical ):
• Low compression
• Leaking cylinder head gaskets
• Worn camshaft
• Camshaft drive belt slipped or stripped
Was a problem found? — Verify repair Go to Step 18
18 1. Review all diagnostic procedures within this table. 2. If all procedures have been completed and nomalfunctions have been found, review/inspect the
following:
• Visual/physical inspection
• Tech 2 data
• All electrical connections within a suspected circuit and/or system
Was a problem found? — Verify repair Go to Step 19
19 Is the ECM programmed with the latest software release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved? — Verify repair Go to Step 20
20 Replace the ECM. Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure. — Verify Repair —
Step
Action Value(s) Yes No

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ISUZU KB P190 2007

ENGINE DRIVEABILITY AND EMISSIONS 6E–239
ROUGH, UNSTABLE, OR INCORRECT IDLE, STALLING SYMPTOM
DEFINITIONS: Engine runs unevenly at idle. If severe,
the engine or vehicle may shake. Engine idle speed
may vary in RPM. Either condition may be severe
enough to stall the engine.
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. Check for faulty, plugged or incorrectly installed PCV valve.
2. Verify that the PCV system is not plugged.
Was a problem found? — Verify repair Go to Step 5
5 1. Check for incorrect idle speed. Ensure that the following conditions are present.
• Engine fully warm
• Accessories are “Off”
2. Using a Tech 2, monitor IAC position.
Is the IAC position within the specified values? 20-30 Steps Go to Step 7Go to Step 6
6 1. Visually/physically inspect for the following conditions:
• Restriction of the 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 7

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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

ENGINE DRIVEABILITY AND EMISSIONS 6E–241
17 Perform the procedure in Fuel System Pressure Test(Refer to 6E-108 “Fuel System Diagnosis ”) to
determine if there is a problem with fuel delivery.
Was a problem found? — Verify repair Go to Step 18
18 Check for the following engine mechanical problems (refer to Engine Mechanical ):
• Low compression
• Leaking cylinder head gaskets
• Worn camshaft
• Sticking or leaking valves
• Valve timing
• Broken valve springs
• Camshaft drive belt slipped or stripped
Was a problem found? — Verify repair Go to Step 19
19 1. Review all diagnostic procedures within this table. 2. If all procedures have been completed and nomalfunctions have been found, review/inspect the
following:
• Visual/physical inspection
• Tech 2 data
• All electrical connections within a suspected circuit and/or system
Was a problem found? — Verify repair Go to Step 20
20 Is the ECM programmed with the latest software release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved? — Verify repair Go to Step 21
21 Replace the ECM. Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure. — Verify Repair —
Step
Action Value(s) Yes No

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ISUZU KB P190 2007

6E–242 ENGINE DRIVEABILITY AND EMISSIONS
SURGES AND/OR CHUGS SYMPTOM
DEFINITIONS: See the illustration below. Feels like the
vehicle speeds up and slows down with no charge in the
accelerator pedal.
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 Be sure that the driver understands A/C compressor operation as explained in the owner’s manual. Inform
the customer how the A/C clutch operate.
Is the customer experiencing a normal condition? — System OK Go to Step 5
5 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 6
6 Observe the throttle position display on the Tech 2 while slowly increasing throttle pedal.
Is the throttle position at the specified value and
steady in any position?
—Go to Step 7Refer to
Diagnostic
Trouble Code P0123 for further
diagnosis
7 Check the knock sensor wire, shield wire, or installation condition.
Was a problem found? — Verify repair Go to Step 8
8 Run Engine. Check the fuel control Heated Oxygen Sensor
(HO2S). When monitored on the Tech 2, the HO2S
should respond quickly to different throttle positions. If
it doesn’t check for silicon or other contaminates from
fuel or use of improper sealant. The sensors may
have a white powdery coating. Silicon contamination
sends a rich exhaust signal which causes the ECM to
command an excessively lean air/fuel mixture.
Was a problem found? — Verify repair Go to Step 9

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ISUZU KB P190 2007