compression ratio ISUZU KB P190 2007 Workshop Owner's Guide
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Page 2408 of 6020

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
Page 2422 of 6020

6E–252 ENGINE DRIVEABILITY AND EMISSIONS
12 Monitor “B1S1 (Bank 1 Sensor 1) Status ” on the Tech
2.
Is the “ B1S1 (Bank 1 Sensor 1) Status ” in the rich
condition? — 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 for proper ignition voltage output with a spark tester.
Was the problem found? — Verify repair Go to Step 16
16 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 17
17 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 suspencion of alcohol contamination,
completely drain the fuel, replace by fuel from known
vehicle source. — Verify repair Go to Step 18
18 Check the exhaust system for a possible restriction: • Damaged or collapsed pipes
• Internal muffler failure
Was a problem found? — Verify repair Go to Step 19
19 Check for the following engine mechanical problems (refer to Engine Mechanical ):
• Low compression
• Leaking cylinder head gaskets
• Worn camshaft
• Loose timing belt
Was a problem found? — Verify repair Go to Step 20
20 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 21
Step
Action Value(s) Yes No
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Page 2427 of 6020

ENGINE DRIVEABILITY AND EMISSIONS 6E–257
14 Monitor “B1S1 (Bank 1 Sensor 1) Status ” on the Tech
2.
Is the “ B1S1 (Bank 1 Sensor 1) Status ” in the rich
condition? — Verify repair Go to Step 15
15 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 16
16 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 17
17 Check for proper calibration of the speedometer. Does the speed indicated on the speed meter closely
match the vehicle speed displayed on the Tech 2? — Go to Step 19Go to Step 18
18 Diagnose and repair the inaccurate speedometer condition as necessary. Refer to Vehicle Speed
Sensor in Electrical Diagnosis . — Verify Repair —
19 Check for proper calibration of the fuel gauge. Was a problem found? — Verify repair Go to Step 20
20 Check for the following engine mechanical problems (refer to Engine Mechanical ):
• Low compression
• Worn camshaft
• Sticking or leaking valves
• Valve timing
Was a problem found? — Verify repair Go to Step 21
21 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 22
22 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 23
23 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
Page 2429 of 6020

ENGINE DRIVEABILITY AND EMISSIONS 6E–259
16 1. Remove excessive carbon buildup with a topengine cleaner. Refer to the instructions on the top
engine cleaner can.
2. Perform the exhaust emission test.
Does the vehicle pass the test? — System OK Go to Step 18
17 Perform the exhaust emission test. Does the vehicle pass the test? — System OK Go to Step 18
18 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 and excessively lean air/fuel mixture.
Was a problem found? — Verify repair Go to Step 19
19 Monitor “ B1S1 (Bank 1 Sensor 1) Status ” on the Tech
2.
Is the “ B1S1 (Bank 1 Sensor 1) Status ” in the rich
condition? — Go to Step 20Go to Step 21
20 1. Check items that can cause the engine to run rich. Refer to Diagnostic Aids in DTC P1167 “Fuel
Supply System Rich During Deceleration Fuel Cut
Off” . Make any necessary repairs.
2. Perform the exhaust emission test.
Does the vehicle pass the test? — System OK Go to Step 22
21 1. Check items that can cause the engine to run lean. Refer to Diagnostic Aids in DTC P1171 “Fuel
Supply System Lean During Power Enrichment” .
Make any necessary repairs.
2. Perform the exhaust emission test.
Does the vehicle pass the test? — System OK Go to Step 22
22 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
Was a problem found? — Verify repair Go to Step 23
23 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 24
Step
Action Value(s) Yes No
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Page 2481 of 6020

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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Page 2501 of 6020

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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Page 2508 of 6020

Engine Mechanical – V6 Page 6A1–29
2.3 Engine Misfire without Internal Engine
Noises
Cause Correction
Abnormalities, severe cracking, bumps or missing areas in
the accessory drive belt.
Abnormalities in the accessory drive system and/or
components may cause engine speed variations that result
in a misfire diagnostic trouble code (DTC). A misfire code
may be present without an actual misfire condition. Replace the accessory drive belt, refer to 3.5
Accessory
Drive Belt.
Refer to 6C1-2 Engine Management – V6 – Diagnostics to
check for DTCs.
W orn, damaged or misaligned accessory drive components
and excessive pulley run-out may lead to a misfire DTC.
A misfire code may be present without an actual misfire
condition. Inspect the components and repair or replace as required.
Refer to 6C1-2 Engine Management – V6 – Diagnostics to
check for DTCs.
Loose or incorrectly fitted flexplate or crankshaft balancer
assembly.
A misfire DTC may be present without an actual misfire
condition. Repair or replace the flexplate or crankshaft balancer as
required, refer to 3.13 Crankshaft Balancer Assembly
or 4.3 Flexplate Assembly.
Refer to 6C1-2 Engine Management – V6 – Diagnostics to
check for DTCs
Restricted exhaust system.
A severe restriction in the exhaust flow can cause
significant loss of engine performance and may set a DTC.
Possible causes of restrictions in the exhaust system
include collapsed/dented pipes and blocked mufflers and/or
catalytic converters. Repair or replace exhaust system components as required,
refer to 8B Exhaust System.
Refer to 6C1-2 Engine Management – V6 – Diagnostics to
check for DTCs
Incorrectly installed or damaged vacuum hoses. Repair or replace vacuum hoses as required.
Incorrect sealing between the intake manifold and cylinder
heads, upper intake manifold and lower intake manifold,
throttle body and intake manifold. Repair or replace the intake manifold, throttle body gaskets,
cylinder heads, throttle body as required.
Incorrectly installed or damaged barometric
pressure(BARO) sensor and/or seal. The seal should not
be torn or damaged. Repair or replace the BARO sensor and/or seal as
required, refer to 6C1-3 Engine Management – V6 –
Service Operations.
Incorrectly installed or damaged EVAP purge solenoid
and/or O-ring seal. Repair or replace the EVAP purge solenoid and/or seal as
required, refer to 6C1-3 Engine Management – V6 –
Service Operations
W orn or loose stationary hydraulic lash adjusters (SHLA)
and/or rocker arms.
The SHLAs, rocker arms 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.
Excessive oil pressure.
A lubrication system with excessive oil pressure may lead
to excessive lash adjuster pump-up and loss of
compression. 1 Perform an oil pressure test, refer to 3.1
Engine Oil.
2 Repair or replace the engine oil pump as required, refer to 3.17 Oil Pump Assembly.
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Page 2509 of 6020

Engine Mechanical – V6 Page 6A1–30
Cause Correction
Faulty cylinder head gasket and/or cracking or other
damage to the cylinder head 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.
W orn piston rings.
Oil consumption may or may not cause the engine to
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.
A damaged crankshaft reluctor wheel.
A damaged crankshaft reluctor wheel can result in different
symptoms depending on the severity and location of the
damage.
Systems with severe reluctor ring damage may exhibit
periodic loss of crankshaft position, stop delivering a signal,
and then re-sync the crankshaft position.
Systems with slight reluctor ring damage may exhibit no
loss of crankshaft position and no misfire may occur,
however, a DTC may set. Replace the crankshaft as required, refer to 4.6
Crankshaft and Main Bearings.
Refer to 6C1-2 Engine Management – V6 – Diagnostics to
check for DTCs
2.4 Engine Misfire with Abnormal Internal Lower Engine Noises
Cause Correction
Abnormalities, severe cracking, bumps or missing areas in
the accessory drive belt.
Abnormalities in the accessory drive system and/or
components may cause engine speed variations that result
in a misfire diagnostic trouble code (DTC). A misfire code
may be present without an actual misfire condition. Replace the accessory drive belt, refer to 3.5
Accessory
Drive Belt.
Refer to 6C1-2 Engine Management – V6 – Diagnostics to
check for DTCs
W orn, damaged or misaligned accessory drive components
and excessive pulley run-out may lead to a misfire DTC.
A misfire code may be present without an actual misfire
condition. Inspect the components and repair or replace as required.
Refer to 6C1-2 Engine Management – V6 – Diagnostics to
check for DTCs
Loose or Incorrectly fitted flexplate or crankshaft balancer
assembly.
A misfire code may be present without an actual misfire
condition. Repair or replace the flexplate or crankshaft balancer as
required, refer to 3.13 Crankshaft Balancer Assembly
or 4.3 Flexplate 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.
W orn crankshaft thrust bearing.
Severely worn thrust surfaces on the crankshaft and/or
thrust bearing may permit fore and aft movement of the
crankshaft and create a DTC without an actual misfire
condition being present. Replace the crankshaft and/or bearings as required, refer to
4.6 Crankshaft and Main Bearings.
Refer to 6C1-2 Engine Management – V6 – Diagnostics to
check for DTCs
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Page 2510 of 6020

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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Page 2517 of 6020

Engine Mechanical – V6 Page 6A1–38
2.15 Engine Compression Test
A compression pressure test of the engine cylinders determines the condition of the rings, the valves and the head
gasket.
Preliminary Steps
1 Ensure the battery is fully charged.
2 Remove the spark plugs from all cylinders, refer to 6C1-3 Engine Management – V6 – Service Operations.
NOTE
DTCs will set when the fuel system or the ignition
system is disabled and the engine is cranked.
Disregard DTCs that set under this condition.
3 Disable the fuel system by removing the fuel pump relay, refer to 8A Electrical Body & Chassis.
4 Start the engine to use any residual fuel from the fuel lines.
4 Disable the ignition coils by removing fuses 34 and 35, refer to 8A Electrical Body & Chassis .
5 Using Tech 2, command the throttle plate to wide open throttle.
Engine Cylinder Compression Test
1 Install the compression tester to cylinder number 1.
2 W hile observing the compression tester reading, turn the ignition to the START position for several seconds and then allow the ignition to return to the ON position.
3 Record the highest compression reading obtained.
4 Repeat the engine compression test for each cylinder.
Test Result Evaluation
Normal engine compression pressure builds quickly and evenly to over 965 kPa. In addition, the lowest reading of an
engine cylinder should not be less than 70 percent of the highest reading. If any cylinder fails the compression test,
adding 15 ml of engine oil to the suspected cylinder may help isolate the following fault condition.
1 A fault condition in the piston rings will produce the following result:
• A low compression on the first engine cycle
• The compression tends to build-up with the succeeding engine rotation.
• The compression improves with the addition of engine oil.
2 A fault condition in an intake or exhaust valve will produce the following result:
• A low compression on the first engine cycle
• The compression does not build with the succeeding engine rotation.
• The compression does not improve with the addition of engine oil.
3 A fault condition in the cylinder head gasket will produce the following result:
• A low compression on the first engine cycle
• The compression does not build with the succeeding engine rotation.
• The compression does not improve with the addition of engine oil.
• The suspected cylinders are positioned adjacent to each other.
• The engine oil may be contaminated with engine coolant.
• The engine coolant may be contaminated with engine oil.
Once the fault has been identified, refer to the relevant service procedure and reinstall the removed components.
Using Tech 2, clear DTCs.
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