DVNE PRODUT SERVE NORMTON SUBJET: Electronic uel Management (EM) System - Update No: 60 Revised DTE: 10/09 MODELS: M40/44/49 This PS is an update and replacement for PS #60 dated 5/09. t includes additional troubleshooting flowcharts. The Electronic uel Management (EM) System controls the position of the carburetor choke plate during engine starting and warm-up. The system is controlled by an Electronic ontrol Unit (EU) and a geared-down stepper motor that actuate the choke. thermistor attached to the cylinder head reads engine temperature while the program in the EU senses engine speed. Together, this information allows the EU to determine the appropriate choke position for starting the engine. 1
SSEMBLY 2 B 1. Electronic ontrol Unit (EU) 1. EU - Mounting Bracket 2. EU - Harness Plugs 3. EU - Part Number Label E B. hoke Link. Stepper Motor 1. Stepper Lever D. Speed nput onnection E. Power Harness (EM). onnection KH. uel Solenoid. Plug G. Thermistor H. able Tie. Engine Harness Plugs (2) D 1. Engine (6-pin) Harness onnector J. pplication (6-pin) Harness onnector G 2 1 B 1 3 H D J G 1 2
SERVE PREUTONS VOLTGE SPKES, can damage the Electronic ontrol Unit (EU). To avoid such damage please follow these instructions carefully. VOLTGE SPKE Voltage Spike or static electricity can damage the EU, during the following service activities: Disconnecting Harnesses Starting the Engine Before Making Weld Repairs Disconnecting the Battery onnecting the Battery harging the Battery Use the following procedures to avoid voltage spikes. Disconnecting Harnesses The ignition switch must be in the O position when disconnecting or connecting any wire harnesses (engine, application, or EM). TE: Never disconnect any electrical connection with engine running. Starting the Engine Never use a battery charger to directly start the engine. Use only a fully charged battery properly installed. Never start the engine if the battery cables are loose or poorly connected to the battery terminals. Never start the engine if any wire harnesses (engine, application, or EM) are loose or poorly connected. Before Making Weld Repairs 1. The ignition switch must be in the O position. 2. Remove EU bracket assembly and unplug harnesses from rear of EU. 3. Disconnect and remove the battery. 4. Disconnect (6-pin) harness plug (J) between engine and application. WRNNG Battery posts, terminals and related accessories contain lead and lead compounds - chemicals known to the State of alifornia to cause cancer and reproductive harm. Wash hands after handling. Disconnecting the Battery TE: Never disconnect the battery with the engine running. 1. The ignition switch must be in the O position when disconnecting the battery. 2. lways disconnect the NEGTVE ( ) cable first. 3. Disconnect the POSTVE ( + ) cable last. Off onnecting the Battery 1. The ignition switch must be in the O position when connecting the battery. 2. lways connect the POSTVE ( + ) cable first. 3. onnect the NEGTVE ( ) cable last. harging the Battery ( + ) ( ) 1. gnition switch must be in the O position. 2. lways disconnect the NEGTVE ( ) battery cable before charging. 3. lways attach the POSTVE (+) charger clamp to the (+) terminal of the battery first. 4. ttach the NEGTVE ( ) clamp to the ( ) terminal of the battery last. WRNNG DO T REMOVE OVER 3
GENERL TROUBLESHOOTNG Refer to SSEMBLY art on page 2 for (tem) references. Before performing troubleshooting procedures, check the EU part number (3). Does the number on the EU label match the part number for the engine model/application shown below? Engine Model pplication M40/44 Tractor 96350 M40/44 ZT-Mower (Zero Turn) 96351 M49 Tractor 96352 M49 ZT-Mower (Zero Turn) 96353 EU Part No. Replace the EU 1. Turn the key to the O position. 2. Disconnect the fuel solenoid plug (). 3. Disconnect the EM power connector (). 4. onnect an adaptor wire harness (L) (optional) into connector (). 5. onnect power source clips to the adaptor harness ends and attach to a 12V power source (K). 6. Rotate voltmeter selector to the V position.. onnect the test leads to the solenoid plug () pins. 8. Take reading. Short ircuited EU (Very little or no reading) Replace EU. EU OK (Reading between ~12-18 V) Perform a tractor harness troubleshooting procedure to locate the short. DOES THE ENGNE: T RNK? Turn ignition switch to the O position. s the main tractor fuse blown? L Using a voltmeter (M), check EU () for a short. heck battery condition, battery ground cable ( ) connection to tractor frame, ignition switch, electrical safety interlock switches. heck that the 6-pin engine /application harness connection (J) is secure. lso see troubleshooting procedures WRNNG DO T REMOVE OVER 12V K 12V M 0 10 20 30 O 300mV 10 V USED OM V V OM 4
DOES THE ENGNE: RNK BUT T STRT? s the carburetor flooded? 1. Turn the key to the O position. 2. Disconnect the fuel solenoid plug (). 3. Disconnect engine power harness plug () from the EM power plug () and connect it to the fuel solenoid (). 1. Turn the key to the RUN (On) position. 2. Raise the hood and manually open the choke. t will not damage the stepper motor to force the lever arm open. Note: s long as the key switch is not moved to the "Off" position, the choke will remain open. 4. Manually set the choke to start engine. OPEN HOKE OPEN 3. lose the hood and sit in the seat. 4. Turn the key to the STRT position. Engine is OK. See EM TROUBLESHOOTNG page 6. The EM system is OK. gnition arburetion ompression 5
EM TROUBLESHOOTNG Refer to SSEMBLY art on page 2 for (tem) references. Reconnect EM system to the engine, if previously disconnected. Stepper Lever (1) moves to ULL choke and stays. nitial actuation is correct. 1. Turn the key to the O position. 2. Manually move the choke to the OPEN position. Does the engine start / run correctly? Replace the Thermistor (G). Retest engine - OK? OPEN 3. Have an observer note the stepper lever (1) actuation as the key is turned to the Run/On position. Replace the EU. Stepper Lever (1) moves to ULL choke and stays. Retest engine - OK? or B Stepper Lever (1) moves to ULL choke but then immediately returns to OPEN choke. or Stepper Lever (1) does not move. The EM system is OK. 6
B Stepper Lever (1) moves to ULL choke but then immediately return to OPEN choke. Replace the Thermistor (G). Does stepper lever move to full choke and stay? Test wiring harnesses to ensure continuity between corresponding pins and plugs. f needed, repair/replace parts and reconnect harnesses. Replace the EU. Replace the Thermistor (G) Replace the EU (G). t this point the EM system is in working order. Stepper Lever (1) does not move. Replace the Stepper Motor (). Turn the key to the O position. Disconnect and reconnect the EM power harness () to make sure the connections are correctly plugged in and secure. t this point the EM system is in working order.