M11 Series – Service Manual – 006-005   Cylinder Misfires or Smokes

WARNING  Due to the stroke of the CELECT™ and CELECT™ Plus injectors on M11 engines, DO NOT use the mechanical method to perform a cylinder cutout test. When an injector on a CELECT™ or CELECT™ Plus engine is mechanically shorted (barred), the push rods can be thrown free causing personal injury. Refer to the Automated Cylinder Performance Test to perform the test on CELECT™ or CELECT™ Plus engines.

The following methods can be used to find the cylinder(s) causing misfire/white smoke.

• Mechanical cylinder cutout test (STC engines only)
• Exhaust manifold temperature
• Tilting back exhaust manifold
• Automated cylinder performance test (CELECT™ and CELECT™ Plus only)

NOTE: Do

not
run the automated Cylinder Performance Test on engines that are smoking at idle.

Perform the Automated Cylinder Performance Test at least twice.

Refer to the appropriate electronic service tool manual.

Minimum cylinder contribution is 71%.

WARNING  Due to the stroke of the CELECT™ and CELECT™ Plus injectors on M11 engines, DO NOT use the mechanical method to perform a cylinder cutout test. When an injector on a CELECT™ or CELECT™ Plus engine is mechanically shorted (barred), the push rods can be thrown free causing personal injury. Refer to the appropriate electronic service tool manual.

The following methods can be used to find the cylinder(s) causing misfire/white smoke.

• Mechanical cylinder cutout test (STC engines only)
• Exhaust manifold temperature
• Tilting back exhaust manifold
• Automated cylinder performance test (CELECT™ and CELECT™
  Plus only)

Cut out each cylinder while watching the exhaust smoke. Refer to the appropriate electronic service tool manual.

Replace the injector in the cylinder that causes a reduction in smoke when cut out.

WARNING  Due to the stroke of the CELECT™ and CELECT™ Plus injectors on M11 engines, DO NOT use the mechanical method to perform a cylinder cutout test. When an injector on a CELECT™ or CELECT™ Plus engine is mechanically shorted (barred), the push rods can be thrown free causing personal injury. Refer to the Automated Cylinder Performance Test to perform the test on CELECT™ or CELECT™ Plus engines.

The following methods can be used to find the cylinder(s) causing misfire/white smoke.

• Mechanical cylinder cutout test (STC engines only)
• Exhaust manifold temperature
• Tilting back exhaust manifold
• Automated cylinder performance test (CELECT™ and CELECT™
  Plus only)

Remove the rocker lever cover. Refer to Procedure

003-011-002.

Hold the injector plunger down while the engine is running at low idle. This will stop the fuel flow to that injector.

If the smoke disappears when an injector is cutout, this is the cylinder causing the smoke.

Replace the injector in the cylinder(s) that causes a reduction in smoke when cut out.

To locate a smoking cylinder, use a pyrometer or infrared temperature gun to measure the exhaust manifold surface temperature at each cylinder port.

The maximum exhaust manifold surface temperature at idle is 143°C [290°F].

A cylinder is smoking if:

• The exhaust manifold surface temperature at that exhaust port exceeds the above specification.
• The exhaust manifold surface temperature at that port is significantly higher than that for the other cylinder ports.

NOTE: If this test is inconclusive, tilt back the exhaust manifold to locate the smoking cylinder.

WARNING  Do not place hand on the exhaust manifold if the engine is hot or emiting thick black smoke.

An alternative method is to place your hand on the exhaust manifold at each cylinder port. A smoking cylinder will feel hot.

Replace the injector in the cylinder that is producing the smoke.

Refer to Procedure 006-026.

Loosen the exhaust manifold capscrews, and tilt the exhaust manifold back.

Idle the engine.

Observe the smoking cylinder.

Replace the injector in the cylinder that is producing the smoke.

Refer to Procedure 006-026.