Mityvac MV5545 User Manual

USER’S MANUALHave a technical question?If you have questions, or require technicalservice, please contact our trained servicetechnicians at:1-314-679-

Flex Hose ConnectionsIn many cases it is convenient to connect the FST Pro into the fueldelivery system at a location where a flexible rubber hose is

Form 824127 Page Number - 11Principle of OperationFuel Delivery BasicsModern fuel injected engines rely on precision fuel delivery toperform at peak o

In regards to return fuel systems, knowing the pressure and flow atidle is a very good indication as to whether the fuel system isfunctioning properly

Fig. 20Form 824127 Page Number - 13When the valve is rotated to the BYPASS position pointing up, fuel isrouted through the bypass port located on the

Fig. 21Fig. 22Page Number - 14 Form 824127Types of Fuel Delivery SystemsFor the purpose of accurately applying and testing with the FST Pro,today’s fu

Fig. 25Fig. 24Fig. 23Form 824127 Page Number - 15Returnless fuel systems (mechanically regulated) were pioneered byChrysler in the mid-90s. Since that

Fig. 27Fig. 26Page Number - 16 Form 824127Electronically RegulatedFord began developing an electronically regulated returnless fueldelivery system in

Form 824127 Page Number - 17Fuel System ComponentsThe modern fuel delivery system is comprised of several criticalcomponents. A malfunction of one or

Page Number - 18 Form 824127A clogged inlet strainer can starve the fuel pump of fuel, causingit to cavitate. Cavitation will create rapid changes in

Fig. 28Fig. 29Fig. 30Form 824127 Page Number - 19Setup and InstallationDetermining Where to Install the FSTInline ConnectionRegardless of the type of

ContentsIntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Safety Precautions . . . . . . . .

Fig. 35reduce fuel spillage, whenever possible, try to select the requiredadapters before disconnecting the fuel line, and have them ready toinstall.S

7. Connect the hose extending from the flowmeter connectionlabeled “IN”, to the other end of the adapter (Fig. 36).8. Install the second FST connectio

Fig. 40Fig. 39Fig. 41Read topof floatPage Number - 22 Form 824127Testing and DiagnosticsTesting and diagnostic procedures vary depending on the type o

Fig. 42Fig. 43Form 824127 Page Number - 23At idle, the volume of fuel flowing through the tester should remainsteady between 0.3 and 0.6 gallons per m

Fig. 44Page Number - 24 Form 824127continues to experience symptoms of a fuel delivery malfunction, itcould be caused by contaminated fuel, faulty fue

Form 824127 Page Number - 25Under-restricting Fuel Pressure RegulatorAn under-restricting pressure regulator will cause the idle pressure inZones 1 an

Fig. 46Fig. 45Fig. 47Page Number - 26 Form 824127Returnless Fuel Delivery Systems(Mechanically Regulated)At this point, it is assumed that the FST has

Fig. 49Fig. 48Form 824127 Page Number - 27OPEN position.Peak Demand Test7. Note the vehicle’s engine size and maximum engine speed (RPM).Refer to the

Fig. 50A clogged inlet strainer can cause the fuel pump to cavitate becauseit is starved for fuel. Cavitation will create rapid changes in fuel densi-

Fig. 51Fig. 52Fig. 53After connecting the FST, it is normal to have air trapped in thefuel lines and flowmeter. Cycling the ignition switch (or cranki

IntroductionThe Mityvac FST Pro Fuel System Tester is an advanceddiagnostic tool designed for troubleshooting and pinpointingcommon automotive fuel de

Fig. 55Fig. 549. With the car idling, rotate the flow control valve past the 90°CLOSED position towards BYPASS (Fig. 54). Adjust the valve untilthe fl

ty, causing the float in the FST flowmeter to bounce up and downduring the peak flow and/or capability test. It can also cause the nee-dle on the pres

Fig. 56Fig. 57Page Number - 32 Form 8241275. Turn off the engine and immediately clamp off the FST inlet hoserunning to the tester from the fuel suppl

the hose is clamped, quickly disconnect the hose from the fuelsystem before the pressure has time to build. Try to keep a shoptowel wrapped around the

Page Number - 34 Form 824127Engine Size Engine Speed (RPM)liters CID 3000 4000 5000 6000 7000 80001.0 61 0.05 0.06 0.07 0.09 0.10 0.121.2 73 0.06 0.07

Form 824127 Page Number - 35Engine Size Engine Speed (RPM)liters CID 3000 4000 5000 6000 7000 80001.0 61 0.19 0.23 0.26 0.34 0.38 0.451.2 73 0.23 0.26

Page Number - 36 Form 824127ResultsScenarioIdlePressureIdle FlowPeak PressurePeak FlowPotential Causes1 Normal NormalGreater thanmaximum fuelvolume re

Appendix BReturn Fuel System Diagnostic GuideScenario 2Diagnosis:A restriction to the supply of fuel to the engine such as aclogged inlet strainer, in

Page Number - 38 Form 824127ResultsScenarioIdlePressurePeak FlowPeak Demand PressurePotential Causes1 NormalNormal.7 to 1.0 GPM(2.5 to 4.0 LPM)NormalL

Form 824127 Page Number - 39Appendix CReturnless (Mechanically Regulated)Fuel System Diagnostic GuideScenario 2Diagnosis:A restriction to the supply o

MVA5552MVA5549MVA509Standard Kit ComponentsPart Number Description824141 High Pressure Gauge824149 Pressure Relief Hose (1/8"/3mm ID x 6'/1.

Page Number - 40 Form 824127*See Appendix A for maximum engine fuel volume requirementInlet strainer/sockECM/PCMPressure Transducer/SensorFuel FilterF

Form 824127 Page Number - 41Appendix DReturnless (Electronically Regulated)Fuel System Diagnostic GuideScenario 2Diagnosis:A restriction to the supply

Page Number - 42 Form 824127Lincoln Industrial Standard WarrantyLIMITED WARRANTYLincoln warrants the equipment manufactured and supplied by Lincoln to

Form 824127 Page Number - 5Service PartsPart Number Description1 824182 Flow Tube Shield2 824177 Male Quick-Connect Fitting3 824176 Bypass Port4 82417

Description Applications Order No.ReferenceNo.GM/Chrysler Right AngleTest Port AdapterGM & some Chryslervehicles with7⁄16" x 20thread test po

Description Applications Order No.ReferenceNo.M16 x 1.5Ball Nose AdapterEuropean vehicleswith CIS fuel systemMVA51911A11BM16 x 1.5 Adapter GM Vortec M

AssemblyFor flexibility and ease of storage, the FST Pro features a modulardesign that is quick to assemble and breakdown. Proper assemblyfor testing

Fig. 9Fig. 11Fig. 10Fuel RailBanjoFittingBanjo BoltBanjo AdapterFuel FilterForm 824127 Page Number - 9To release the connection, press and hold the re