5. FUEL INJECTION SYSTEM MXU 500EXi/MXU500i SERVICE INFORMATION GENERAL INSTRUCTIONS Scooter services can be done with the engine installed in the frame. Be sure to relieve the fuel pressure before fuel pump or fuel hose removal. Bending or twisting the control cables will affect operation and could cause the cables to stick or bind, resulting in loss of vehicle control. Work in a fully ventilated area. Smoking or allowing flames or sparks in the work area or where gasoline is stored can cause a fire or explosion. Do not apply the Carburetor Cleaners to the inside of the throttle body, which is coated with molybdenum. Do not snap the throttle valve from fully open to fully close after the throttle cable has been removed; it may cause incorrect idle speed. Do not loosen or tighten the painted bolts and screws of the throttle body. Loosening or tighten them can cause throttle and idle valve synchronization failure. Seal the cylinder head intake ports with tape or a clean towel to prevent dirt and debris from entering the intake ports after the throttle body has been removed. Do not damage the throttle body. It may cause incorrect throttle and idle valve synchronization. Do not take the fuel pump on the ground downward. Always replace the packing when the fuel pump is removed. The electronic fuel injection system is equipped with the self-diagnostic system. If the Check Engine Lamp "CELP" illuminate while riding, follow the self-diagnostic procedures to solve the problem. A faulty AFI problem is often related to poorly connected or corroded connectors. Check those connections before proceeding. When disassembling the fuel injection parts, note the location of the O-rings. Replace them with new ones upon reassembly. Do not disconnect the battery negative (-) or positive (+) cable while engine is running, it may cause ECU damage. Do not disconnect or connect the ECU connector during the ignition switch "ON"; it may cause the ECU damage. 5-1