Navistar MaxxForce DT Diagnostic Manual page 88

DIAGNOSTIC MANUAL
To prevent personal injury or death, do not exceed local speed limit laws or drive too fast
for conditions when performing Lug Down Test.
Step
2A Using EST, go to Sessions > Performance. Find an open
stretch of road in order to perform Lug Down Test. When
driving conditions are safe, select the record snapshot icon
from the toolbar, and perform Lug Down procedure below:
1. Select a suitable high range gear (Example: In a
10 speed gearbox, select the 8th speed).
2. Allow engine speed to drop to 1000 rpm.
3. Press accelerator pedal fully to the floor, and
accelerate to rated engine speed.
After Lug Down Test is complete, stop recording and save
snapshot.
Step
2B Check for low fuel rail pressure. Using EST with ServiceMaxx™
software, use the playback feature and graph the following
signal values from Lug Down Test:
Signal Values:
• Engine Speed
• Fuel Rail Pressure (FRP)
• Fuel Rail Pressure Desired (FRPD)
Compare snapshot to Graph 3 and associated Graph Analysis
page 124.
Is FRP signal operating as per Graph 3 Graph Analysis?
84
WARNING
Action
Action
https://www.truck-manuals.net/
Decision
Go to step 2B
Decision
Yes: Go to step 2C
No: Diagnose and repair low fuel
rail pressure (See Performance
Diagnostics section in Engine
Diagnostic Manual). After repairs
are complete, retest for original
problem.