11. Injector Disable Test; Automatic Test - Auto Run - Navistar International DT 466 Diagnostic/Troubleshooting Manual

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11. Injector Disable Test

Figure 315
Purpose
To determine the cause of rough engine idle
The Injector Disable Tests can only be done with the
EST; MasterDiagnostics® software is required.
The Injector Disable Tests allows the technician to
shut-off injectors to determine if a specific cylinder is
contributing to engine performance. Injectors can be
shut off one at a time, alternative cylinders at a time
or alternative cylinders plus one.
Alternate cylinders are every other cylinder in firing
order.
Firing order: 1–5–3–6–2–4
When all cylinders are active, the contribution of
each cylinder is 17% of its overall effect to maintain
governed speed. When three cylinders are shut off,
contribution of each remaining cylinder is 33% of
its overall effect to maintain governed speed. The
technician should monitor fuel rate and engine load.
NOTE: The Relative Compression Test 12 should
be done after doing the Injector Disable Test 11
to distinguish between an injector or mechanical
problem.
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
6 PERFORMANCE DIAGNOSTICS
Tools
•
•
NOTE: Before doing the Automatic Test or Manual
Test for injector disable, make sure Tests 1 through
10 were completed and the following conditions are
maintained:
•
•
•
Automatic Test – Auto Run
The Automatic Test is best done when comparing
cylinder to cylinder test data.
NOTE: If MasterDiagnostics® software does not have
the Automatic Test (auto run feature), Injector Disable
– Manual Test in Section 3 for procedure to compare
cylinder to cylinder.
NOTE: Do KOER Standard test before doing this test.
possible death or damage to the engine or vehicle
– comply with the following:
When running the engine in the service bay, make
sure the parking brake is set, the transmission is
in neutral, and the wheels are blocked.
EGES-270-1
Follow all warnings, cautions, and notes.
© August 2008 Navistar, Inc.
EST with MasterDiagnostics® software
EZ-Tech® interface cable
Make sure accessories are turned off. (Example
– engine fan and air conditioning) Items cycled
during this test could corrupt the test results.
Maintain engine idle.
Keep EOT within a 2 °C (5 °F) range from the
beginning to the end of the test. EOT affects
injection timing; too much of a change in EOT
temperature could corrupt the test results.
WARNING: To avoid serious personal injury,