Navistar MaxxForce 9 - Graph 3: Lug down Test (Engine Speed, Frp, and Frpd)

DIAGNOSTICMANUAL
10.3.GRAPH3:LUGDOWNTEST(ENGINESPEED,FRP ,ANDFRPD)
1.FuelRailPressureDesired(FRPD)
(psi)[Orange]
2.Engineload(percent)[Green]
3.AcceleratorPedalPosition1
(APP1)(percent)[Blue]
4.FuelRailPressure(FRP)(psi)
[Red]
Figure28Graph3:LugDownTest(EngineSpeed,FRP ,andFRPD)
GraphAnalysis:
Thisgraphshowsafuelmanagementsystemoperatingasdesigned.Thistestdoesnotgivepassorfailresults.
ItonlyallowstheusertovalidateFuelRailPressure(FRP)andFuelRailPressureDesired(FRPD)signal
valuesunderload.Asenginerpmincreases,FuelRailPressure(FRP)shouldsteadilyincrease.LowFRPwill
causelowIntakeManifoldPressure(IMP).DiagnoselowFRPconcernsbeforediagnosinglowIMPconcerns.
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