Navistar International DT 466 Diagnostic/Troubleshooting Manual page 271

5. Connect Fuel/Oil Test Coupler to test fitting.
6. Drive vehicle and make sure engine operating
temperature reaches 70 °C (158 °F) or higher.
7. Find a long, open stretch of road.
8. When driving conditions are safe, select a suitable
gear, press accelerator pedal fully to the floor, and
accelerate to rated speed at 100% load.
9. Memorize gauge reading for fuel inlet restriction.
After parking vehicle,
Diagnostic Form; do not record reading while
driving.
• If inlet restriction exceeds specification, find
the restriction on the suction side of the fuel
system and correct.
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
6 PERFORMANCE DIAGNOSTICS
record reading on
EGES-270-1
Follow all warnings, cautions, and notes.
© August 2008 Navistar, Inc.
• If inlet restriction is to specification, but
fuel pressure is below specification, test
Operation of Fuel Pump in Test 6 of this
section.
• If fuel pump is operating correctly, replace fuel
regulator valve.
• If inlet restriction and fuel pressure are to
specification, continue with performance
diagnostics.
267