Section 8.6 MBE Cylinder Cutout Test

Section 8.6
MBE Cylinder Cutout Test

This test continually measures the torque of the engine. When a designated cylinder is switched off, the injector is disabled causing the engine speed to decrease. The remaining cylinders will correct for the missing cylinder and return to the correct idle speed. The change in engine torque will indicate the power loss of a particular cylinder. A low change in engine torque may indicate a faulty cylinder.‪

To start a Cylinder Cutout Diagnostic Test:‪

  1. The engine must be on.
  2. The engine must be at idle (no other option is available).

Notes on MBE cylinder cutout test:‪

  • This test will check the baseline torque prior to each cylinder being cutout, unlike DDEC test that only makes an initial baseline measurement. Because of this, the test will take longer to run than a DDEC cutout test.
  • The results of this test should be evaluated by the relative torque value of each cylinder. A significantly lower value indicates this cylinder may have a problem.
  • In Automatic mode, the test runs through each cylinder one at a time and measures the torque as each one is switched on and off.
  • In Manual mode, the user may switch the selected cylinder on or off as desired. The torque will be measured in the same manner for both types of tests.
  • Upon exiting the test, all cylinders are automatically turned back on.

Unit Fuel Injectors and Unit Pumps Technician's Guide - 7SE500
Generated on 10-13-2008

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