Fuel Injector Balance Test with Scan Tool
Diagnostic Instructions
Circuit/System Description
When conditions arise in cylinder balancing, a scan tool output
control test function is provided to help in locating the cause. A
compression test can be used to decide whether the cause should be
attributed to the engine or the injection system. Once the
condition has been limited to the injectors, further tests can
determine which injector is responsible for the condition in
cylinder balancing. The test consists of 2 modes (A, B), which are
conducted in different test conditions.
Circuit/System Testing
Using a scan tool, perform the Fuel Injector Balance test
following the instructions.
Mode A
Quantity correction output by selected cylinder In this test mode,
the engine is running with the fuel balancing control correction
values enabled. The correction quantity shows an offset, which is
added to the injected quantity to establish a vibration-free
running of the engine. The cylinder selective engine speed is also
provided. A higher cylinder balancing quantity correction shows an
injector, which needs greater time to inject an amount of fuel to
produce the requested torque.
Mode B
Output of rotational speeds of selected cylinders for shut off
cylinder balancing quantities In this test mode, the engine is
running with the fuel balancing control correction values disabled.
The cylinder selective engine speed is provided and the engine
running behavior without Fuel Balancing Control values can be
monitored.
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