6 PERFORMANCE DIAGNOSTICS 263
Boost Possible Causes
• Intake leaks (hoses, clamps)
•Boostleaks
• Restricted intake or exhaust
• Exhaust leaks
• Low fuel pressure
• Low ICP
• Contro l system faults
• Failed EGR control valve
• Failed EGR control valve
• Inoperative fuel injectors
• Failed turbocharger
• Diamond Logic® engine brake malfunction
• Biased BAP, EBP, ICP or MAP sensors
• Power cylinder condition
Injection Control Pressure Possible Causes
Low injection control pressure
• Injection co ntrol pressure system leakag e
• Failed IPR wiring (power and control)
• Failed IPR valve
• Failed injector
• Cracked or porous high-pressure rail
• Injector oil inlet adapter O-rings
• Injector oil inlet adapter
• O-ring for high-pressure oil rail
• End plugs in high-pressure oil rail
• Low oil pressure
• Inoperative high-pressure oil pump
• Failed ICP sensor circuit
• Failed ICP sensor
• Inoperative brake shut-off valve of Diamond
Logic® engine brake
• Brake pressure relief valve (optional)
If relief v alve is leaking, the brake shut-off valve
is suspect.
• If ECM detect low boost pressure, an incorrect
feedback signal from APS or the ICP sensor,
the E CM commands the IPR valve to reduce
injection control pressure.
High injection control pressure
• Aerated lube oil
• Bias high ICP sensor – low duty cycle
Erratic injection control pressure
• ICP sensor
•IPRwiring
•IPRvalve
• Middle seal IPR valve
Brake control pressure
• Failed BCP sensor circuit
• Failed BCP sensor
• Inoperative brake shut-off valve of Diam
ond
Logic® engine brake
• Brake control pressure system leakage
EGES-270-1
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
Follow all warnings, cautions, and notes.
©August 2008 Navistar, Inc.
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