A diesel machine operator reports a dead cylinder.
What test would you run?
A Cylinder run out
B Blow-by
C Overflow
D Cylinder cut out
E Coolant pressure
The correct answer and explanation is:
The correct test to run in this case is D Cylinder cut out.
A cylinder cut-out test is typically performed when a diesel engine operator reports a dead cylinder, meaning that one of the engine’s cylinders is not firing properly. The purpose of this test is to isolate and identify any issues related to a specific cylinder. This test helps determine whether a cylinder is failing to contribute to the engine’s power production due to mechanical or fuel delivery issues.
During a cylinder cut-out test, the mechanic or technician selectively disables individual cylinders while the engine is running, usually by cutting off the fuel supply or deactivating the injector for that particular cylinder. As each cylinder is cut out, the engine’s performance will be observed. If cutting out a particular cylinder causes a noticeable drop in engine performance, the issue is likely isolated to that cylinder. Conversely, if cutting out a cylinder doesn’t change the performance of the engine, it suggests that the cylinder was already “dead” and not contributing to the engine’s power.
The test can help diagnose several problems that may cause a cylinder to fail, such as poor fuel injection, compression loss, or a malfunctioning valve. It is important to perform this test while the engine is running, as it provides real-time information about how the engine responds to each cylinder’s deactivation.
While other tests like a blow-by test (B) can help detect issues with piston rings or cylinder wall wear, or a coolant pressure test (E) can check for leaks, these would not specifically pinpoint the dead cylinder in this scenario. Therefore, the cylinder cut-out test is the most effective way to isolate the issue and determine the exact cause of the cylinder failure.