Fuel System

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MasterCraft University 2008-2009 • Fuel Systems • Page 1

2008 Millennium Fuel Pump Module Functional Description(Photos on following pages)

Fuel Flow Through Fuel Pump Module TheaccompanyingfiguresdescribethefunctionoftheMil-lenniumin-tankfuelpumpmodule.Thebottomofthismoduleremainsincontactwihthefueltankbottomatalltimes. Formostoperatingconditions,fuel ispresentunderthepumpmoduleand ispulledby the fuelpumps (A)throughtheinletfilters(B).Whenoperating,thepumpsreducethepressureinsidethelowerreservoir(C),whichliftstheinletvalves(D)andallowsfueltoenterfromthetank.Fuelispumpedintotheregulator-filterhousing(E)andintothebypassregulator(F).Fuelconsumedbytheenginepassesthroughthesmall-particle(10-12micron)filter(G)andexitsthemoduleattheSAEfitting(H).Theremainingpumpflow(bypassfuel)returnsottheupperreservoir(I)throughthehose(J).Thisbypassflowkeepstheupperreservoirfullandoverflowing. Uner“low-fuel”operatingconditions,thereisnofuelunderthepumpmodule.Theinletvalvesfallandcreateasealwiththebottomofthelowerreservoir.Thiscausesfueltobedrawnfromtheupperreservoir(I)throughthereservoirfilter(K)andacalibratedholeinthepumpplate(L). This allows for a continuous supply of fuel to theengineduring low-fuelconditionsas the in-tank fuel issloshingaway fromthereservoir inletandbackagain.Once fuel returns to the reservoir inlet, thevalvesarelifted,fuelisdrawnfromthetankandthereservoirbe-ginstorefillwithbypassflowfromtheregulator.

2009 Millennium Fuel Module

MasterCraft University 2008-2009 • Fuel Systems • Page 2

I

C

D

MasterCraft University 2008-2009 • Fuel Systems • Page 3

FG

J

KA

L

B

F H

E

G

Kj

Tank vent tube

Electrical connector

Fuel outlet to en-gine, need release tool to disconnect,

tube rotates 360 degrees

Service filter annually; remove

snap ring and cap assembly to

accessPressure regulator, vacuum reference tub not used; ser-

viceable by remov-ing snap ring

Fuel reservoir

Inlet filters; not in-tended to be serviced but can be

Stud to ground filter

and flange to pump ground

Serviceable fuel filter

Fuel supply from pumps

Fuel bypass flow from the regula-tor, directed downward into the fuel reservoir

MasterCraft University 2008-2009 • Fuel Systems • Page 4

Bypass pressure regulator

O-ring seals with cup; lube with oil when re-installing regulator

Bypass flow out

Removable snap-rings for filter and regulator replacement

Fuel outlet filter; replace annually

O-ring seals with cup; lube with oil when re-installing cap

Fuel flow to engine

Fuel flow in

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Fuel Module (Pump) Matrix 99-09

MasterCraft University 2008-2009 • Fuel Systems • Page 8

Fuel Module (Pump) Matrix 99-09