Navistar MaxxForce 15 - Step 1 Check for an exhaust system restriction by performing the following Exhaust System Restriction Test:

ENGINESYSTEMS17
cylinderhead.Theintakemanifoldisanintegralpart
ofthecylinderheadcasting.
IftheEGRcontrolvalveisclosed,onlylteredintake
airowsthroughtheETV,mixingduct,andintothe
intakemanifold.
Duringcoldweather,theColdStartFuelIgniter(CSFI)
rapidlyheatstheintakeairbyinjectingandigniting
smallquantitiesoffuelintothemixingduct.
Aftercombustion,gasesexitthroughthecylinder
headexhaustvalvesandports.Theexhaustgas
isforcedthroughtheexhaustmanifoldwhere,
dependingontheEGRvalveassemblyposition,
issplitbetweentheEGRsystemandtheexit
paththroughthehigh-pressureturbochargerand
low-pressureturbocharger.
Theexhaustgasesowfromthelow-pressure
turbochargerthroughthevehicleaftertreatment
systemtotheexhausttailpipe.
AirManagementComponents
Turbochargers
TheMaxxForce®15engineisequippedwithan
electronicallycontrolled,pneumaticallyactuatedtwo
stageturbochargingsystem.Thissystemprovides
highlevelsofchargeairpressuretoimproveengine
performanceandhelpreduceemissions.Becauseof
itsabilitytogenerateveryhighchargeairpressure
levels,thesystemisttedwithanaircontrolvalve
tocontrolover-boostandsurgingconditions.The
aircontrolvalveissuppliedcompressedairfromthe
vehicleairsupplytank.Thecompressedairowto
thewastegateactuatoriselectronicallycontrolled
bytheaircontrolvalvebasedonthePulseWidth
Modulated(PWM)signalsuppliedbytheEngine
ControlModule(ECM).Thehighandlow-pressure
turbochargersareinstalledasanassemblyonthe
exhaustmanifold,ontherightsideoftheengine.