8.FUEL INJECTOR OPERATION
WARNING: The fuel system is under a constant pressure (even with the engineoff). Before testing or ser-
vicing any fuel system hose, fitting or line, the fuel system pressure mustbe released. Failure to follow
these instructions can result in personal injury or death.
CAUTION: After each Fuel Injector actuation, start the engine to clean thecylinder of fuel. Failure to do so
could cause engine damage.
Remove special tool C4390.
Start the engine and allow the fuel pressure to reach maximum pressure.
Ignition on, engine not running.
Using the scan tool, actuate the Fuel Injector for the cylinder that indicated the misfire.
Monitor the fuel pressure gauge.
Does the fuel pressure gauge indicate a drop in fuel pressure?
Ye s>>
Go To 9
No>>
Go To 10
NOTE: Turn the ignition off, remove the Fuel Pressure gauge, and connect the fuel lines before continuing.
9.ENGINE MECHANICAL
Check for any of the following conditions/mechanical problems.
ENGINE VACUUM - must be at least 13 inches in neutral
ENGINE VALVE TIMING - must be within specifications
ENGINE COMPRESSION - must be within specifications
ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks.
ENGINE PCV SYSTEM - must flow freely
TORQUE CONVERTER STALL SPEED - must be within specifications
POWER BRAKE BOOSTER - no internal vacuum leaks
FUEL - must be free of contamination
CAM LOBES - must not be worn excessively
CYLINDER LEAKAGE TEST - must be within specifications
VALVE SPRINGS - cannot be weak or broken
Are there any engine mechanical problems?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 17
10.FUEL INJECTOR
Turn the ignition off.
Disconnect the Fuel Injector harness connector of the misfiring cylinder.
Ignition on, engine not running.
NOTE: When a Misfire is detected for a particular cylinder, the PCM will shut down that cylinders Injector
Control circuit.
With the scan tool, erase DTCs.
Using a 12-volt test light connected to 12-volts, probe the Injector Control circuit.
With the scan tool, actuate the Fuel Injector.
Does the test light blink/flicker?
Ye s>>
Replace the Fuel Injector.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 11
NOTE: The pressure should not fall below 241 KPa (35 psi).
Does the pressure fall below the listed specification?
Ye s>>
Replace the leaking Fuel Injector(s).
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 8
8.FUEL INJECTOR OPERATION
WARNING: The fuel system is under a constant pressure (even with the engineoff). Before testing or ser-
vicing any fuel system hose, fitting or line, the fuel system pressure mustbe released. Failure to follow
these instructions can result in personal injury or death.
CAUTION: After each Fuel Injector actuation, start the engine to clean thecylinder of fuel. Failure to do so
could cause engine damage.
Remove special tool C4390.
Start the engine and allow the fuel pressure to reach maximum pressure.
Ignition on, engine not running.
Using the scan tool, actuate the Fuel Injector.
Monitor the fuel pressure gauge.
Does the fuel pressure gauge indicate a drop in fuel pressure?
Ye s>>
Go To 9
No>>
Go To 10
NOTE: Turn the ignition off, remove the Fuel Pressure gauge, and connect the fuel lines before continuing.
9.ENGINE MECHANICAL
Check for any of the following conditions/mechanical problems.
ENGINE VACUUM - must be at least 13 inches in neutral
ENGINE VALVE TIMING - must be within specifications
ENGINE COMPRESSION - must be within specifications
ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks.
ENGINE PCV SYSTEM - must flow freely
TORQUE CONVERTER STALL SPEED - must be within specifications
POWER BRAKE BOOSTER - no internal vacuum leaks
FUEL - must be free of contamination
CAM LOBES - must not be worn excessively
CYLINDER LEAKAGE TEST - must be within specifications
VALVE SPRINGS - cannot be weak or broken
Are there any engine mechanical problems?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 17
8.FUEL INJECTOR OPERATION
WARNING: The fuel system is under a constant pressure (even with the engineoff). Before testing or ser-
vicing any fuel system hose, fitting or line, the fuel system pressure mustbe released. Failure to follow
these instructions can result in personal injury or death.
CAUTION: After each Fuel Injector actuation, start the engine to clean thecylinder of fuel. Failure to do so
could cause engine damage.
Remove special tool #C4390.
Start the engine and allow the fuel pressure to reach maximum pressure.
Ignition on, engine not running.
Using the scan tool, actuate the Fuel Injector.
Monitor the fuel pressure gauge.
Does the fuel pressure gauge indicate a drop in fuel pressure?
Ye s>>
Go To 9
No>>
Go To 10
NOTE: Turn the ignition off, remove the Fuel Pressure gauge, and connect the fuel lines before continuing.
9.ENGINE MECHANICAL
Check for any of the following conditions/mechanical problems.
ENGINE VACUUM - must be at least 13 inches in neutral
ENGINE VALVE TIMING - must be within specifications
ENGINE COMPRESSION - must be within specifications
ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks.
ENGINE PCV SYSTEM - must flow freely
TORQUE CONVERTER STALL SPEED - must be within specifications
POWER BRAKE BOOSTER - no internal vacuum leaks
FUEL - must be free of contamination
CAM LOBES - must not be worn excessively
CYLINDER LEAKAGE TEST - must be within specifications
VALVE SPRINGS - cannot be weak or broken
Are there any engine mechanical problems?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 17
NOTE: The pressure should not fall below 241 KPa (35 psi).
Does the pressure fall below the listed specification?
Ye s>>
Replace the leaking Fuel Injector(s).
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 8
8.FUEL INJECTOR OPERATION
WARNING: The fuel system is under a constant pressure (even with the engineoff). Before testing or ser-
vicing any fuel system hose, fitting or line, the fuel system pressure mustbe released. Failure to follow
these instructions can result in personal injury or death.
CAUTION: After each Fuel Injector actuation, start the engine to clean thecylinder of fuel. Failure to do so
could cause engine damage.
Remove special tool #C4390.
Start the engine and allow the fuel pressure to reach maximum pressure.
Ignition on, engine not running.
Using the scan tool, actuate the Fuel Injector.
Monitor the fuel pressure gauge.
Does the fuel pressure gauge indicate a drop in fuel pressure?
Ye s>>
Go To 9
No>>
Go To 10
NOTE: Turn the ignition off, remove the Fuel Pressure gauge, and connect the fuel lines before continuing.
9.ENGINE MECHANICAL
Check for any of the following conditions/mechanical problems.
ENGINE VACUUM - must be at least 13 inches in neutral
ENGINE VALVE TIMING - must be within specifications
ENGINE COMPRESSION - must be within specifications
ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks.
ENGINE PCV SYSTEM - must flow freely
TORQUE CONVERTER STALL SPEED - must be within specifications
POWER BRAKE BOOSTER - no internal vacuum leaks
FUEL - must be free of contamination
CAM LOBES - must not be worn excessively
CYLINDER LEAKAGE TEST - must be within specifications
VALVE SPRINGS - cannot be weak or broken
Are there any engine mechanical problems?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 17
NOTE: The pressure should not fall below 241 KPa (35 psi).
Does the pressure fall below the listed specification?
Ye s>>
Replace the leaking Fuel Injector(s).
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 8
8.FUEL INJECTOR OPERATION
WARNING: The fuel system is under a constant pressure (even with the engineoff). Before testing or ser-
vicing any fuel system hose, fitting or line, the fuel system pressure mustbe released. Failure to follow
these instructions can result in personal injury or death.
CAUTION: After each Fuel Injector actuation, start the engine to clean thecylinder of fuel. Failure to do so
could cause engine damage.
Remove special tool #C4390.
Start the engine and allow the fuel pressure to reach maximum pressure.
Ignition on, engine not running.
Using the scan tool, actuate the Fuel Injector.
Monitor the fuel pressure gauge.
Does the fuel pressure gauge indicate a drop in fuel pressure?
Ye s>>
Go To 9
No>>
Go To 10
NOTE: Turn the ignition off, remove the Fuel Pressure gauge, and connect the fuel lines before continuing.
9.ENGINE MECHANICAL
Check for any of the following conditions/mechanical problems.
ENGINE VACUUM - must be at least 13 inches in neutral
ENGINE VALVE TIMING - must be within specifications
ENGINE COMPRESSION - must be within specifications
ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks.
ENGINE PCV SYSTEM - must flow freely
TORQUE CONVERTER STALL SPEED - must be within specifications
POWER BRAKE BOOSTER - no internal vacuum leaks
FUEL - must be free of contamination
CAM LOBES - must not be worn excessively
CYLINDER LEAKAGE TEST - must be within specifications
VALVE SPRINGS - cannot be weak or broken
Are there any engine mechanical problems?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 17
8.FUEL INJECTOR OPERATION
WARNING: The fuel system is under a constant pressure (even with the engineoff). Before testing or ser-
vicing any fuel system hose, fitting or line, the fuel system pressure mustbe released. Failure to follow
these instructions can result in personal injury or death.
CAUTION: After each Fuel Injector actuation, start the engine to clean thecylinder of fuel. Failure to do so
could cause engine damage.
Remove special tool #C4390.
Start the engine and allow the fuel pressure to reach maximum pressure.
Ignition on, engine not running.
Using the scan tool, actuate the Fuel Injector.
Monitor the fuel pressure gauge.
Does the fuel pressure gauge indicate a drop in fuel pressure?
Ye s>>
Go To 9
No>>
Go To 10
NOTE: Turn the ignition off, remove the Fuel Pressure gauge, and connect the fuel lines before continuing.
9.ENGINE MECHANICAL
Check for any of the following conditions/mechanical problems.
ENGINE VACUUM - must be at least 13 inches in neutral
ENGINE VALVE TIMING - must be within specifications
ENGINE COMPRESSION - must be within specifications
ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks.
ENGINE PCV SYSTEM - must flow freely
TORQUE CONVERTER STALL SPEED - must be within specifications
POWER BRAKE BOOSTER - no internal vacuum leaks
FUEL - must be free of contamination
CAM LOBES - must not be worn excessively
CYLINDER LEAKAGE TEST - must be within specifications
VALVE SPRINGS - cannot be weak or broken
Are there any engine mechanical problems?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 17
NOTE: The pressure should not fall below 241 KPa (35 psi).
Does the pressure fall below the listed specification?
Ye s>>
Replace the leaking Fuel Injector(s).
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 8
8.FUEL INJECTOR OPERATION
WARNING: The fuel system is under a constant pressure (even with the engineoff). Before testing or ser-
vicing any fuel system hose, fitting or line, the fuel system pressure mustbe released. Failure to follow
these instructions can result in personal injury or death.
CAUTION: After each Fuel Injector actuation, start the engine to clean thecylinder of fuel. Failure to do so
could cause engine damage.
Remove special tool #C4390.
Start the engine and allow the fuel pressure to reach maximum pressure.
Ignition on, engine not running.
Using the scan tool, actuate the Fuel Injector.
Monitor the fuel pressure gauge.
Does the fuel pressure gauge indicate a drop in fuel pressure?
Ye s>>
Go To 9
No>>
Go To 10
NOTE: Turn the ignition off, remove the Fuel Pressure gauge, and connect the fuel lines before continuing.
9.ENGINE MECHANICAL
Check for any of the following conditions/mechanical problems.
ENGINE VACUUM - must be at least 13 inches in neutral
ENGINE VALVE TIMING - must be within specifications
ENGINE COMPRESSION - must be within specifications
ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks.
ENGINE PCV SYSTEM - must flow freely
TORQUE CONVERTER STALL SPEED - must be within specifications
POWER BRAKE BOOSTER - no internal vacuum leaks
FUEL - must be free of contamination
CAM LOBES - must not be worn excessively
CYLINDER LEAKAGE TEST - must be within specifications
VALVE SPRINGS - cannot be weak or broken
Are there any engine mechanical problems?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 17
NOTE: The pressure should not fall below 241 KPa (35 psi).
Does the pressure fall below the listed specification?
Ye s>>
Replace the leaking Fuel Injector(s).
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 8
8.FUEL INJECTOR OPERATION
WARNING: The fuel system is under a constant pressure (even with the engineoff). Before testing or ser-
vicing any fuel system hose, fitting or line, the fuel system pressure mustbe released. Failure to follow
these instructions can result in personal injury or death.
CAUTION: After each Fuel Injector actuation, start the engine to clean thecylinder of fuel. Failure to do so
could cause engine damage.
Remove special tool #C4390.
Start the engine and allow the fuel pressure to reach maximum pressure.
Ignition on, engine not running.
Using the scan tool, actuate the Fuel Injector.
Monitor the fuel pressure gauge.
Does the fuel pressure gauge indicate a drop in fuel pressure?
Ye s>>
Go To 9
No>>
Go To 10
NOTE: Turn the ignition off, remove the Fuel Pressure gauge, and connect the fuel lines before continuing.
9.ENGINE MECHANICAL
Check for any of the following conditions/mechanical problems.
ENGINE VACUUM - must be at least 13 inches in neutral
ENGINE VALVE TIMING - must be within specifications
ENGINE COMPRESSION - must be within specifications
ENGINE EXHAUST SYSTEM - must be free of any restrictions or leaks.
ENGINE PCV SYSTEM - must flow freely
TORQUE CONVERTER STALL SPEED - must be within specifications
POWER BRAKE BOOSTER - no internal vacuum leaks
FUEL - must be free of contamination
CAM LOBES - must not be worn excessively
CYLINDER LEAKAGE TEST - must be within specifications
VALVE SPRINGS - cannot be weak or broken
Are there any engine mechanical problems?
Ye s>>
Repair as necessary.
Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)
No>>
Go To 17