Guardian Technologies 4270 manual Test 38 Check OIL Pressure Switch

Page 57

Section 7

DIAGNOSTIC TESTS

NOTE: For units out of warranty, refer to Quicksilver Diagnostic & Service Manual - Diesel, P/N 082034 for further engine service information. This manual can be found at www.guardiangener- ators.com, under “Brochures,Manual & Specs - Recreational Vehicle - Manuals”.

TEST 38 - CHECK OIL PRESSURE SWITCH

DISCUSSION:

Also see “Operational Analysis” on Pages 18-23. The Low Oil Pressure Switch is normally-closed, but is held open by engine oil pressure during cranking and startup. Should oil pressure drop below a safe level, the switch contacts will close to ground the Wire 85 circuit. Engine controller board action will then initiate an automatic shutdown.

If the switch fails CLOSED, the engine will crank and start, but will then shut down after a few seconds.

If the switch fails OPEN, low oil pressure will not result in automatic shutdown.

Figure 7-23. – Oil Pressure Switch

PROCEDURE:

1.Check engine oil level. If necessary, replenish oil level to the dipstick “FULL” mark.

2.Set a VOM to its “Rx1” scale and zero the meter.

3.Connect the meter test leads across the switch terminals, with engine shut down. The meter should read “Continuity”. A small amount of resistance is acceptable.

4.Crank the engine. Oil pressure should open the switch contacts at some point while cranking and starting. Meter should then indicate “Infinity”.

5.If the contacts did not open in Step 5, remove the low oil pres- sure switch and connect an oil pressure gauge in it’s place. Start the engine and measure oil pressure. Pressure should be above 10 psi.

RESULTS:

1.In Step 3, if “Continuity” is not indicated, replace the switch.

2.If oil pressure checked good in Step 5, but Step 4 measured “Infinity,” replace the low oil pressure switch.

3.If oil pressure is below 10 psi, determine cause of low oil pres- sure. Refer to Engine Service manual No. 0E2081 for further engine service information. Verify that the oil is the proper vis- cosity for the climate and season.

4.If all steps check GOOD, go to Test 40.

TEST 39- CHECK CIRCUIT BOARD FOR

GROUND

DISCUSSION:

If the engine shuts down immediately after start switch is released, a possible cause would be the ground wire is faulty, forcing the unit to ground the cir- cuit board through the start/stop switch. Once the switch is released, the ground is removed from the board, causing the unit to shut down.

PROCEDURE:

1.Remove Wire 0 from the circuit board on Terminal 2.

2.Set a VOM to measure continuity.

3.Place one test lead on Wire 0, previously removed and the other test lead on clean ground. Continuity should be mea- sured.

4.Reconnect wire, making sure it has good contact on Pin 2 of the circuit board.

RESULTS:

1.If continuity was not measured in step 3, replace wire.

2.If continuity was measured in step 3, replace the circuit board.

TEST 40- TEST WATER TEMPERATURE

SWITCH

DISCUSSION:

This normally-open thermostatic switch has a sensing tip, which is immersed in engine coolant. Should coolant temperature exceed approximately 245-266 F, the switch contacts will close to ground Terminal 12 on the circuit board. Circuit board action will then shutdown the engine.

PROCEDURE:

1.Disconnect Wire 85 from the switch terminal.

2.Set a VOM to measure continuity.

3.Place one test lead on switch and the other on clean ground. Infinity should be measured.

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Contents Diagnostic Repair Manual Replacement Parts SafetyTable of Contents 57-59 Magnetism Electromagnetic FieldsElectromagnetic Induction More Sophisticated AC Generator Simple AC GeneratorGenerator Operating Diagram Field Boost Generator AC Connection SystemLine Breakers 120 VAC only Connection for 120/240 VAC Dual Voltage LIC Grit or Abrasive to Clean Slip Rings Rotor AssemblyBrush Holder Battery Charge ComponentsExcitation Circuit Components GeneralAdjustment Procedure Adjust POT LED162 Voltage RegulatorControl Panel Components Control Panel Component IdentificationEffects of Dirt and Moisture Cleaning the GeneratorDrying the Generator Insulation Resistance TestersStator Insulation Resistance Brushing and Vacuum CleaningCloth or Compressed AIR Stator SHORT-TO-GROUND TestsMegohmmeter Testing Rotor InsulationVOM MetersMeasuring AC Voltage Measuring DC VoltageMeasuring AC Frequency Measuring CurrentMeasuring Resistance Ohms LAW Electrical UnitsIntroduction Operational AnalysisCircuit CONDITION- OFF Circuit CONDITION- PRE-HEAT Circuit CONDITION- Cranking Circuit CONDITION-RUNNING Circuit CONDITION- Shutdown Circuit CONDITION- Fault Shutdowns Engine Control Circuit Board BatteryChecking Battery State of Charge Effects of TemperatureCharging a Battery Adding WaterSTART/STOP Switch Preheat SwitchAMP Fuse Starter Contactor & MotorFuel Injection Pump Engine GovernorFuel NOZZLES/INJECTORS Glow PlugsAdapter LOW OIL Pressure Switch LOW OIL Pressure Switch High Coolant Temperature SwitchEngine Protective Devices Overspeed ProtectionTroubleshooting Flowcharts Troubleshooting Flowcharts Problem 3 No Battery Charge Output Troubleshooting Flowcharts Troubleshooting Flowcharts Troubleshooting Flowcharts Troubleshooting Flowcharts Troubleshooting Flowcharts Test 1- Check NO-LOAD Voltage Frequency Test 2 Check & AdjustTest 4- Fixed Excitation TEST/ROTOR AMP Draw Test 3- Test Excitation Circuit BreakerRe-connect Wire 11 and Wire 22 to the Voltage Regulator Test 5- Wire ContinuityTest 6- Check Field Boost Set a VOM to its Rx1 scaleModel QP75D Test 7 Test Stator DPE WindingTest 9- Check Brush Leads Test 8- Check Sensing Leads / Power Windings159W 184WTest 11- Check Rotor Assembly Tance Tests ProcedureTest 10 Check Brushes & Slip Rings Test 12 Check Main Circuit Breaker Test 15 Check Battery Charge OutputTest 13- Check Load Voltage Frequency Test 14- Check Load Watts & AmperageTest 16 Check Battery Charge Rectifier Battery Charge Rectifier BCR is a full wave rectifierShort to Ground Set a VOM to read battery voltage 12 VDC Test 19- Test PRE-HEAT SwitchTest 18 TRY Cranking the Engine Test 20- Check Fuel PumpTest 23- Check Power Supply to Circuit Board Test 22- Check Battery & CablesDisconnect the connector from the wires of the fuel pump Test 21- Check 14 AMP FuseNot Activated Test 24 Check START-STOP SwitchTest 26- Test Starter Contactor Test 27 Check Starter MotorConditions Affecting Starter Motor Performance Pinion Checking the PinionTools for Starter Performance Test Measuring CurrentTachometer Testing Starter MotorTest Bracket Starter motor test bracket may be made as shown in FigureTest 30 Check Wire Test 29 Check Wire 14 Power SupplyIf Wire 18 checks GOOD, proceed to Problem 8 Section Test 28- Check Fuel SupplyTest 32- Test Preheat Contactor Test 33- Test Glow PlugsTest 34- Test D1 Diode Test 35- Check Valve Adjustment Remove the valve cover from engine Disconnect the batteryTest 36- Fuel Injector Pump Adjust the regulated pressure on the gauge to 80 psi If fuel is noted, proceed to next step in flowchartDown Test / Compression Test Repeat Steps 1 through 8 on remaining cylinderTest 38 Check OIL Pressure Switch Test 40- Test Water Temperature SwitchTest 39- Check Circuit Board for Ground Test 43 Check Wire 15 for Short to Ground If continuity is measure, replace the switchComponents for Short to Ground Major Disassembly Belt Tensioning RE-ASSEMBLYFAN Belt Line Corner UP Between 5˚ to 10˚Section Exploded Views / Part Numbers Stator Assembly Rotor AssemblyFlywheel Assembly Bearing Carrier, FrontBase Frame Drawing No D2357-A Door, Service Front Door, Service RearBase Frame Weldment Slide Latch FlushEnclosure Drawing No D2358-D Cover, Access Electrical Cover, Access LiftGasket, Electrical Access Decal, Battery +Views / Part Cover Plate, Scroll Weldment 25 26 Assembly Marine Control Board Assembly, Potted RegulatorRectifier, Battery Charging Wire Assembly #Intake and Exhaust System Drawing No D2362-B Chamber Air Intake Exhaust GasketAir Filter Hose, Air InletViews / Part Numbers Boot, Battery Cable Fuel Pump AssemblyCable, Battery Wire Assembly, Black #4 GroundCustomer Controls Assembly Drawing No D2364-D Switch, Pushbutton Spst Start / Stop SwitchBoot / Nut / Preheat Switch Boot, Circuit BreakerCamshaft Gear Camshaft AssemblyKEY Gear2630 Liter Diesel Cylinder Head Drawing No D2794 Liter Diesel Crankshaft, Piston and Flywheel Drawing No -B Spring Idler Gear AssemblyThrust Washer OIL Pump CoverIncludes ALL Components Shown below Rocker ARM AssemblyIntake Rocker ARM Exhaust Rocker ARMLiter Diesel Injector Pump Drawing No -C Tank Return Model 04270 To Injection Pump To Fuel Pump 27 25 19 18 HOUSING, Timing Gear 3114 Liter Diesel Water Pump Drawing No Charts Generator Specifications Engine SpecificationsType Quietpact Model ROTOR/STATOR Resistance ValuesPage Data Data Electrical Data C4945 Schematic Drawing No C4945-A ModelC4946-A ElectricalSheet 2 OF4996 REV. O
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