Precautions
Precautions on Fuel System Service
Service operation of any type performed on the fuel system involves a risk of fire and injury if proper precautions are not taken.
Be sure to take the following precautions when working around gasoline or servicing the fuel system.
●Disconnect battery cables except when battery power is required for servicing/inspection.
●Keep the working area well ventilated and away from open flame (such as gas heater) or sparks.
●Do not smoke or allow anyone else to smoke near the working areas.
Post a “NO SMOKING” sign.
●Keep a fully charged 002 fire extinguisher readily available for use.
●Always use appropriate safety equipment and wear safety glasses when working around a pressurized fuel system.
●To avoid potential fire hazards, do not allow fuel to spill on hot engine parts or on operating electrical components.
●Wipe up fuel spills immediately.
●Before loosening or disconnecting the fuel feed line, be sure to relieve the fuel system of fuel pressure by following the fuel pressure relief procedure.
●When disconnecting a fitting on the fuel line, cover the fitting with a shop cloth to soak up the small amount of fuel that may flow out from the disconnected fuel line. Put the used cloth in an approved container.
●Since fuel hose connections vary with the pipe type, connect and clamp each hose using the correct method for each specific connection.
After connecting a hose, check that there is no twist or kink in the hose.
●When installing hose clamps, position tabs to avoid contact with other parts.
●Be sure hoses do not contact rods, levers or other components with engine either operating or at rest.
General Description
Electronic Fuel Injection System Description
The fuel injection system used by the DF150AP/175AP/200AP is a speed—density, multi-point, sequential, electronic fuel injection type.
The fuel injection system is composed of the fuel line components, air intake components, and components for system control (ECM, sensors, switches, etc.)
Fuel Injection Control System Outline
Sensors are mounted at precise locations on the motor to monitor the current conditions of engine operation and send signals to the ECM.
Based on these signals, the ECM determines the optimum fuel injection time duration (fuel amount), fuel injection timing (multi-point sequential timing) and controls the injector operating signals accordingly.
In regards to fuel injection timing, the fuel injection end timing is set depending on engine rpm. The ECM calculates the amount of fuel injection based on the engines operating conditions, and determines the fuel injection start timing.
In the injection timing chart below, the injection end timing is set at 100° ATDC on the compression stroke.
