Manual Test - Navistar International DT 466 Diagnostic/Troubleshooting Manual

246
Figure 319 I6 Injector Disable Test Results
(Auto Run – Graph View)
During Auto Run, injectors are shut off one at a time (1
through 6 in numerical sequence). Baseline data and
results for each cylinder is displayed in the window
(Text View) for I6 Injector Disable Test Results. Test
data for each injector can also be viewed by selecting
the (Graph View).
5. Record data from window (Text View) on
Diagnostic Form.
• If deviation values for average fuel rate and
average engine load are less than the cut
off values for fuel rate and engine load,
the injector is suspect for weak cylinder
contribution.
• If only one deviation value is less than a cut
off value, do not suspect that cylinder.
• If a suspect cylinder(s) is identified, do Test 12
Relative Compression to distinguish between
an injector or mechanical problem.
• If Test 12 shows
mechanically sound, but the Injector Disable
Test shows that one or more cylinders are
bad, continue with step 6.
6. Remove valve cover following procedure in
Engine Service Manual.
7. Replace faulty injector(s) following procedures in
the Engine Service Manual.
8. Test drive vehicle for 20 miles to purge air from
ICP system and fuel supply system. Check for
rough idle.
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
6 PERFORMANCE DIAGNOSTICS
that cylinders are
EGES-270-1
Follow all warnings, cautions, and notes.
© August 2008 Navistar, Inc.
9. If rough idle continues, do the Injector Disable Test
again.
Possible Causes
• Failed connection from wiring harness to injector
solenoid
• Open or shorted wiring harness to injector
solenoid
• Failed solenoid on fuel injector
• Scuffed or damaged injector
• Failed IDM
• Failed ECM

Manual Test

The Manual Test is best done when diagnosing each
cylinder for cold misfire, considering EOT changes.
The EOT indicator will change from red to green when
engine temperature reaches 70 °C (158 °F) or higher.
• If the EOT indicator
comparisons are likely from cylinder to cylinder.
However, when diagnosing a cold misfire, a
technician can listen to tone changes from
cylinder-to-cylinder.
• When the EOT indicator is green and the engine
temperature is 70 °C (158 °F) or higher, fuel rate
and timing are more stable, making comparisons
from cylinder to cylinder more accurate. Overall
engine operation is more stable.
Shut off one injector at a time and listen for changes
in exhaust tone.
NOTE: If any injectors are removed and reinstalled
or replaced, test drive vehicle for 20 miles before
checking for misfire or rough idle.
WARNING: To avoid serious personal injury,
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.
is red, erroneous