Cylinder Balance Testing
CYLINDER BALANCE TEST A cylinder balance test is used to determine if all cylinders are working equally. This test compares the rpm loss between each cylinder and based on the results, helps isolate the problem area. For example, if a 60 rpm drop occurs on the first seven cylinders, but there is no rpm drop on number eight, then there is a problem with the eighth cylinder tested. This test can also be used to isolate lower engine noise to a particular cylinder. If for example, a customer complains of a loss of power, or the engine runs “rough,” you may have to perform a cylinder balance test. RPM loss varies depending on engine size, configuration and extent of the miss. Cutting out one cylinder on a V8 has less rpm drop than removing one cylinder on a six-cylinder engine. It is easier to identify a weak cylinder with a load on the engine. The cylinder balance tests in the VP2000 and Diacom disable secondary ignition to individual cylinders while monitoring the change in rpm. These tests should only be performed under a load because weak cylinders show up better with a load on them. Do not perform this test on engines under NO load, the results will be invalid. 1.
Hook up the VP2000 or Diacom and navigate to the cylinder balance test (power balance test in the VP2000).
2.
For Diacom, follow the on screen prompts.
3.
Using a screwdriver or other mechanical device, hold the throttle open so that the engine runs at approximately 1500 RPM and conduct a balance test for all cylinders and record the RPM drop, by cylinder, below.
4.
Cyl. # 1 _______
Cyl. # 5 _______
Cyl. # 2 _______
Cyl. # 6 _______
Cyl. # 3 _______
Cyl. # 7 _______
Cyl. # 4 _______
Cyl. # 8 _______
Are there any bad cylinders? If so, what are the cylinder number(s)? _____________________________________________
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