MI-04 & MI-07 Basic System Troubleshooting
Contents
1. Pin 3 to Pin 5 Resistance Specification 0 6KQ 30 Adjust your multi meter to the Ohms O setting to obtain the proper values Slide 1392. Basic Troubleshooting e Checking all other Emission Control Sensors and Components Lock Off Valve FTV Pin Pin Arrangement Arrangement A lock off valve can be tested fairly easily with a common digital multi A fuel trim valve FTV can be tested fairly easily with a common digital meter by performing a few simple resistance checks multi meter by performing a simple resistance check Adjust your multi meter to the Ohms Q setting to obtain the proper Adjust your multi meter to the Ohms Q setting to obtain the proper values Put you meter leads across Pin A and Pin B to obtain your values Put your ohm meter across Pin A and Pin B to obtain a reading reading Pin A to Pin B Specification Pin A to Pin B Specification 26 Q 29 20 29 Q Slide 134 Basic Troubleshooting e Checking all other Emission Control Sensors and Components Bosch Oxygen Sensor Pin Arrangement Sensor Heater White Sensor Ground Grey Sensor Signal Black Slide 135 An Oxygen Sensor can be tested fairly easily with a common Digital Voltmeter that has a MIN MAX AVG Function as well as a Bar Graph As Oxygen Sensors age they become lazy and slow to react The Engine Management System is constantly monitoring the reaction time and will store a Fault Code if necessary You can test an Oxygen Sensor for two readings to roughly determine if the Oxygen Sensor is Good or Bad These Te
3. TEE Fitting to the Atmospheric Side of the Mixer It will be the hose that is connected to the Intake Air Stream Top side of the Mixer This hose is called the Bias Line and it is approximately 1 4 in Diameter Hose Remove the Bias Line Hose end from the Mixer a the Fuel Inlet Hose End from the Mixer this hose is approximately 5 8 in in iameter Turn the Key Switch to the ON Position Slide 122 Basic Troubleshooting Checking the LP Gas Fuel Supply Fuel Filter and LP Gas Fuel Lock Off Blow into the Bias Line Hose End When you blow into the Bias Line Hose End you should hear and smell LP Gas Vapor escape from the Mixer Fuel Inlet Hose End If Fuel escapes from the hose end the LP Gas Fuel Lock Off and Pressure Regulator Converter are working If Fuel does not escape from the Mixer Fuel Inlet Hose End continue with the next step If Fuel Vapor did not escape from the Mixer Fuel Inlet Hose End 5 8 in Hose when you blew into the Bias Line 1 4 in Hose the next step is to check the LP Gas Fuel Lock Off Turn the Key Switch to the OFF Position Place your hand onto the LP Gas Fuel Lock Off Turn the Key Switch to the ON Position the SECM will perform a Throttle Spring Test and then activate the LP Gas Fuel Lock Off This takes approximately 1 5 Seconds You hand should feel the LP Gas Fuel Lock Off activate If you feel the LP Gas Fuel Lock Off activate with your hand it
4. of Pressure while Cranking the Engine to Start then the LP Gas Pressure Regulator Converter is good Slide 128 Basic Troubleshooting e Checking the MIXER e For 2 0 2 4L MMC Engines TIER II MI 04 and TIER III MI 07 with the N C For A55 500TR Mixer Remove the four 4 screw holding the Intake Air Stream System Elbow onto the top of the Mixer Look into the bore of the Mixer and make sure it is clean and free of any foreign debris oil that might bind the Air Valve Piston Turn the Key Switch to the Start Position You should see the Air Valve Piston pulsate while the Engine cranks to Start Once the Engine Starts the Air Valve Piston should move up and down as you press and release the Accelerator Pedal If the Air Valve Piston is not actuating as described above remove the Mixer from the Engine and clean it with warm water and a mild detergent or replace the Mixer as necessary GM 4 3L Engine TIER Il MI 04 and TIER III MI 07 with the N CA100TR Mixer Slide 129 Remove the Intake Air Stream Hose from the N CA100TR Intake Air Stream Inlet Place your finger into the N CA100TR Intake Air Stream Inlet and slide it along the top of the Mixer until you touch the Mixer Air Valve Diaphragm Material Turn the Key Switch to the Start Position You should fell the Air Valve Diaphragm Material pulsate while the Engine cranks to Start Once the Engine Starts the Air Valve Diaphragm Material should move u
5. A11 TIER Ill Only on the SECM there should be ZERO 0 Ohms e ifthe LP Gas Fuel Lock Off is activating and you believe it is clogged the LP Gas Fuel Lock Off will need to be removed from the LP Gas Pressure Converter and bench checked with a 12 volt supply and Shop Air Pressure 30 PSI Replace the LP Gas Fuel Lock Off as necessary e Ifthere is still no Vapor Fuel Release from the Mixer Fuel Inlet Hose End 5 8 in when you blow into the Bias Line Hose End 1 4 in then proceed to the LP Gas Pressure Regulator Converter and or Mixer Check Slide 124 Basic Troubleshooting Dither Valve Fuel Trim Valve FTV Inspection Slide 125 Inspect all of the hoses for kinks cracking and rotting Replace as necessary Inspect the routing of all of the Dither Valve Hosing Replace and re rout as necessary Visually inspect the Dither Valve FTV for abrasions or cracking Replace if necessary To ensure the Dither Valve FTV is not leaking a Blow By Test can be performed a With the Engine off disconnect the Electrical Connector to the Dither Valve FTV Locate the hose that connects the Dither Valve FTV to the Tee Connection on the Pressure Regulator Converter a Disconnect the Dither Valve FTV Hose from the Tee Connection on the Pressure Regulator Converter a Lightly blow through the hose into the Dither Valve FTV air should not pass through the Dither Valve FTV when it is de energized If you are able to
6. ODO Marea HAOUNG Eouirvet Tg 200158 BRR TO LA MI 04 amp MI 07 Basic System Troubleshooting Slide 120 Basic Troubleshooting The Woodward Tier II MI 04 and Tier III MI 07 Emission Control Systems are equipped with built in Fault Diagnostics Detected System Faults can be displayed by the Malfunction Indicator Lamp MIL as Diagnostic Fault Codes DFC or Flash Codes Items such as Fuel Level Plugged Fuel Lines Clogged Fuel Filters and Malfunctioning Pressure Regulators may not set a Fault Code by the Small Engine Control Module SECM Methods for troubleshooting Plugged Fuel Lines Clogged Fuel Filters Plugged or Leaking Vapor Lines and Cylinder Tank Problems apply to the Tier Ill and Tier Il Systems as they did with the Pre Tier and Tier Lift Trucks Use the following Procedures and Tips to aid you when troubleshooting the Tier III MI 07 and Tier II MI 04 LP Gas Emission Control Systems Basic Troubleshooting Checking the Ignition System for Spark Remove a Spark Plug Cable End from a Spark Plug on the Engine Get a New Spark Plug take it out of the box and plug it into the Spark Plug Cable End Make sure the Spark Plug and Cable End are making a GOOD Connection Connect the Base of the Spark Plug to aa GOOD Engine Ground Negative Bat Turn the Key Switch to the Start Position the Engine should begin to crank to Start While the Engine is cranking to Start watch the Ele
7. blow air past the Dither Valve FTV when it is de energized the Dither Valve FTV is bad and must be replaced TIER III MI 07 has two 2 Dither Valves FTVs and an Orificed Y Fitting in the Dither Valve Circuit In order to check the Dither Valves you have to block one valve off while you check the second one and then change Valves to check the second one The Orifice Y Fitting must also be checked separately Basic Troubleshooting e Tier Il MI 04 Dither Valve Fuel Trim Valve FTV Inspection e ABlow By Test may also be performed to ensure the Dither Valve FTV ri cycling properly Slide 126 Ensure the Electrical Connector is secure and has made a good connection to the Dither Valve FTV Using the Key Switch Start the Engine Touch the Dither Valve FTV you should feel the Valve being cycled if you do not feel it cycling continue with the check as listed below however you may also have an Electrical Problem with the circuit Locate the hose that connects the Dither Valve FTV to the Tee Connection on the Pressure Regulator Converter Disconnect the Dither Valve FTV Hose from the Tee Connection on the Pressure Regulator Converter Lightly blow through the hose into the Dither Valve FTV you should be able to blow air through the Dither Valve FTV while the Engine is running If you are unable to blow air through the Dither Valve FTV while the Engine is running check all of the fittings and ho
8. ctrodes of the Spark UG you should see a rhythmic Spark at the Electrodes of the Spark ug If there is a rhythmic Spark while Cranking the Engine to Start the Ignition System is working If there is No Spark or Intermittent Spark there is a problem in the Ignition Circuit and you must troubleshoot both the Primary and Secondary Ignition Circuits Slide 121 Basic Troubleshooting Checking the LP Gas Fuel Supply Fuel Filter and LP Gas Fuel Lock Off Inspect ALL Vacuum and Fuel Hoses for cracking abrasions or leaks Replace as necessary Check the LPG Fuel Tank Fuel Level if Fuel Level is low install a full Tank of Fuel on the Lift Truck Also ensure the LP Fuel Tank is installed with the LP Tank Bracket Locator Pin engaging the Alignment Hole Slot on the LP Fuel Tank Ensure the Service Valve Fitting and Swivel are fully engaged and tightly and properly coupled Ensure there is not an extra O Ring between the Service Valve Fitting and the Lift Truck Fuel Hose Swivel make sure the Service Valve has been properly opened and fully Backseated Check for Liquid LP Fuel at the inlet to the LP Gas Fuel Lock Off If there is little or no LP Fuel at the Inlet to the Fuel Lock Off check all of the hoses from the LP Fuel Tank to the Fuel Lock Off and Fuel Filter for blockages If Fuel is present proceed to the next step Locate the TEE Fitting on the LP Gas Pressure Regulator Converter find the Hose that runs from the
9. en Sensor when at operating temperature will output a signal that oscillates between 0 000 and 1 000 Volts You can see this oscillation on you voltmeter if you have the ability to record your measurements with a MIN MAX AVG Function As shown by the pictures to the left CLARK Basic Troubleshooting e Checking all other Emission Control Sensors and Components Temperature Temperature Resistance Resistance C F Ohms ci sieve 5896 4712 3792 A fuel temp sensor can be tested fairly easily with a common digital multi meter by performing a simple resistance check This sensor is known as a NTC Negative Temperature coefficient coolant temperature sensor where temperature increases resistance decreases As such use the table on page 2 to calculate the proper resistance based on your ambient temperature Adjust your multi meter to the Ohms Q setting to obtain the proper values Put your ohm meter across Pin A and Pin B to obtain a reading Slide 138 Basic Troubleshooting e Checking all other Emission Control Sensors and Components Pin 2 to Pin 6 Resistance Specification 0 7KQ 30 Pin 3 to Pin 6 Resistance Specification 1 4KQ 30 Pin 2 to Pin 5 Resistance Specification 1 3KQ 30 The Bosch electronic throttle can easily be tested with a common digital multi meter by performing a few simple resistance checks
10. he Engine is running If you are unable to blow air through the Dither Valve FTV while the Engine is running check all of the fittings and hoses connecting the Dither Valve FTV to the Pressure Regulator and also the opposite side connecting the Dither Valve to the AVV Port on the Mixer If all of the fittings and hoses are clear and in good condition then replace the Dither Valve FTV Slide 127 Basic Troubleshooting Checking the LP Gas Pressure Regulator Converter e Ifthe LP Gas Fuel Lock Off and Dither Valves FTVs are working properly then it will be necessary to check the LP Gas Pressure Regulator Converter and the Mixer e In order to check the LP Gas Pressure Regulator Converter you will need to install a Compound Vacuum Fuel Pump Pressure Gauge into the Expansion Chamber Pressure Check Port of the LP Gas Pressure Regulator Converter e Once the Vacuum Fuel Pump Pressure Gauge is installed into the Expansion Chamber Pressure Check Port turn the Key Switch to the Start Position With the Engine Cranking To Start and the LP Gas Fuel System inspected up to and including the LP Gas Fuel Lock Off you should have approximately 1 5PSI of pressure in the Expansion Chamber of the LP Gas Pressure Regulator Converter If there is not 1 5PSI in the Expansion Chamber the LP Gas Pressure Regulator Converter is bad and needs to be replaced e Ifthe Vacuum Fuel Pump Pressure Gauge reads 1 5PSI
11. is a fairly confident indication that the Fuel Lock Off is working properly and you should proceed to the Dither Valve Fuel Trim Vale Blow By Testing If you did not feel the LP Gas Fuel Lock Off activate with your hand when you turned the Key Switch to the ON Position then turn the Key Switch to the OFF Position and disconnect the Wiring Harness Plug from the Fuel Lock Off Using an approved jumper wire connect one pin of the LP Gas Fuel Lock Off to Battery Positive Using a second approved jumper wire connect the remaining pin of the LP Gas Fuel Lock Off to Battery Negative If when the jumper wires were connected to the LP Gas Fuel Lock Off you could feel it activate with your hand the problem is in the Lift Truck Wiring or the SECM If the LP Gas Fuel Lock Off failed to activate when the jumper wires were connected the LP Gas Fuel Lock Off is bad and needs to be replaced Slide 123 Basic Troubleshooting Checking the LP Gas Fuel Supply Fuel Filter and LP Gas Fuel Lock Off e Ifwhenthe jumper wires were connected to the LP Gas Fuel Lock Off you could feel it activate check the Red and White Wire in the Lift Truck side of the Harness Plug for 12 volts Bat when the Key switch is turned ON if you don not have 12 volts Bat check Fuse F8 the Main Power Relay and the Red and White Wire for problems Also check for continuity between the Black Wire in the Lift Truck Side of the Harness Plug and Pin
12. p and down as the Accelerator Pedal is depressed and released If the Air Valve Diaphragm Material is not actuating as described above remove the Mixer from the Engine and clean it with warm water and a mild detergent or replace any parts or the Mixer as necessary Slide 130 Basic Troubleshooting Checking the TMAP Sensor Verify the TMAP Sensor is mounted tightly into the Manifold Adapter If the TMAP is found to be loose remove the TMAP Retaining Screw and the TMAP Sensor from the Manifold Adapter Visually Inspect the TMAP O Ring Seal for damage Replace as necessary Apply a thin coat of an approved Silicon Lubricant to the TMASP O Ring Seal Re Install the TMAP Sensor into the Manifold Adapter and securely tighten the Retaining Screw For 2 0 2 4L MMC Engines TIER Il MI 04 TMAP Electrical Checks refer to Page 68 of the WOODWARD MI 04 2 0 2 4L LPG SYSTEM SERVICE MANUAL 91505B DRAFT For GM 4 3L Engine TIER II MI 04 TMAP Electrical Checks refer to Page 68 of the WOODWARD MI 04 4 3L LPG SYSTEM SERVICE MANUAL 91507B For 2 0 2 4L MMC Engines TIER III MI 07 TMAP Electrical Checks refer to the Corrective Actions for Fault Codes 331 to 353 on Pages 97 amp 98 of the WOODWARD MI 07 Integrated Engine Control System for 2 0L amp 2 4L MMC Engines LPG Fuel Systems 2007 Emission Certified Systems Service Manual 36520 For GM 4 3L Engine TIER III MI 07 TMAP Electrical Checks refe
13. r to the Corrective Actions for Fault Codes 331 to 353 on Pages 88 amp 89 of the WOODWARD MI 07 Integrated Engine Control System for 4 3L GM Engines LPG Fuel Systems 2007 Emission Certified Systems Service Manual 36516 Basic Troubleshooting e Checking the TMAP Sensor A IMAP sensor can be tested fairly easily with a common digital multi meter by performing a few simple resistance checks Adjust your multi meter to the Ohms Q setting to obtain the proper values Air Temp Signal Sensor PWR 5v ne Sensor PWR 5 Pin 1 to Pin 4 Manifold pressure signal Resistance Specification 2 4K 8 2K Q Pin 3 to Pin 4 Resistance Specification 3 4K 8 2K Q Pin 1 to Pin 2 See TMAP Intake Air Temp Table Slide 131 Basic Troubleshooting TMAP SENSOR IAT TABLE Resistance in Q OHMS Temperature FA E Temperature 20 f Minimum Normal Maximum DA o o o ss6 18 Du 40 ss sa 104 3 0 sa ss 6 68 2 30 338 e Checking the IMAP Sensor TMAP Sensor Pin Arrangement Slide 132 Slide 133 Basic Troubleshooting Checking all other Emission Control Sensors and Components Refer to For TIER II MI 04 2 0 2 4L MMC Engines use the WOODWARD MI 04 2 0 2 4L LPG SYSTEM SERVICE MANUAL 91505B DRAFT For Basic Checks refer to pages 40 to 46 For Electrical Checks refer to Pages 66 to 69 or refer to the Faul
14. ses connecting the Dither Valve FTV to the Pressure Regulator and also the opposite side connecting the Dither Valve to the AVV Port on the Mixer If all of the fittings and hoses are clear and in good condition then replace the Dither Valve FTV Basic Troubleshooting e Tier Ill MI 07 Dither Valve Fuel Trim Valve FTV Inspection e A Blow By Test may also be performed to ensure the Dither Valve FTV is cycling properly e TIER Ill MI 07 has two 2 Dither Valves FTVs and an Orifice Y Fitting in the Dither Valve Circuit In order to check the Dither Valves you have to block one valve off while you check the second one and then change Valves to check the second one The Orifice Y Fitting must also be checked a Ensure the Electrical Connectors are secure and have made a good connection to the Dither Valves FTVs Using the Key Switch Start the Engine Touch the Dither Valves FTVs you should feel the Valves being cycled if you do not feel it cycling continue with the check as listed below however you may also have an Electrical Problem with the circuit Locate the hose that connects the Dither Valves FTVs to the Tee Connection on the Pressure Regulator Converter Disconnect the Dither Valve FTV Hose from the Tee Connection on the Pressure Regulator Converter Lightly blow through the hose into the Dither Valve FTV you should be able to blow air through the Dither Valve FTV while t
15. sts are helpful in diagnosing the part before removing it from the Lift Truck The two Tests are 1 Sensor Switching Test 2 Sensor Heater Circuit Resistance check CLARK Basic Troubleshooting e Checking all other Emission Control Sensors and Components Sensor Heater White ko Sg Ka To test the Oxygen Sensor Heater Circuit Resistance unplug the Oxygen Sensor from the Truck Harness l NOTE Make sure the Engine is cool as close to Room Temperature as possible as this resistance value will change with temperature leaving you with a false bad reading The following readings apply only to the Bosch Oxygen Sensor 1 Set your Multi meter to the Ohms Scale Q 2 Place your Meter Leads across the Sensor Heater Spec 2 10 0 4 two heater Circuit Terminals Mei 3 3 The Heater Circuit Resistance Specification is 2 1 Q 0 4 Ohms Slide 136 Basic Troubleshooting e Checking all other Emission Control Sensors and Components Sensor Signal Black Sensor Ground Grey Average voltage of a good switching sensor is 400 450v Slide 137 TO VERIFY THE OXYGEN SENSOR IS SWITCHING Carefully back probe the Signal Black Wire and the XDRG Ground Grey Wire of the Oxygen Sensor This can be performed from either side of the connector Select DC Volts on the Voltmeter and make sure there are three Decimal Places to the right Example 0 450 Volts An Oxyg
16. t Code Corrective Actions for the specific Sensor or Component with the suspected Fault All of the Fault Codes can be found on Pages 54 to 64 in numerical order For TIER II MI 04 GM 4 3L Engine use the WOODWARD MI 04 4 3L LPG SYSTEM SERVICE MANUAL 91507B For Basic Checks refer to pages 40 to 46 For Electrical Checks refer to Pages 66 to 69 or refer to the Fault Code Corrective Actions for the specific Sensor or Component with the suspected Fault All of the Fault Codes can be found on Pages 54 to 64 in numerical order For TIER III MI 07 2 0 2 4L MMC Engines use the WOODWARD MI 07 Integrated Engine Control System for 2 0L amp 2 4L MMC Engines LPG Fuel Systems 2007 Emission Certified Systems Service Manual 36520 For Basic Checks refer to pages 65 to 82 For Electrical Checks refer to the Fault Code Corrective Actions for the specific Sensor or Component with the suspected Fault All of the Fault Codes can be found on Pages 94 to 110 in numerical order TIER Ill MI 07 GM 4 3L Engine use the WOODWARD MI 07 Integrated Engine Control System for 4 3L GM Engines LPG Fuel Systems 2007 Emission Certified Systems Service Manual 36516 For Basic Checks refer to pages 58 to 74 For Electrical Checks refer to the Fault Code Corrective Actions for the specific Sensor or Component with the suspected Fault All of the Fault Codes can be found on pages 85 to 99 in numerical order
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