32100-ZY5-020 Honda SEE PART DETAILS - PRI; WIRE HARNESS ASSY., MAIN (Honda Code 8007858).

Engine Design
Type ... Six Cylinder, Four StrokeCombustion System ... Direct InjectionBore ... 98.43 mm (3.875 in.)Stroke ... 127 mm (5 in.)Cubic Capacity ... 5.8 liters (354 cu. in.)Compression Ratio ... 16 to 1Number and Arrangement of Cylinders ... 1-6Firing Order ... 1-5-3-6-2-4Rotation of crankshaft (as seen from front of engine) ... ClockwiseRotation of camshaft (as seen from front of engine) ... Clockwise Left side and right side of engine are as seen from flywheel end. No. 1 cylinder is the front cylinder of the engine.Engine Serial Number
ENGINE SERIAL NUMBER LOCATIONThe engine serial number is located on the left hand side of the block below the fuel injection pump on the auxiliary drive housing.The first two characters of the serial number stand for the engine family and type. TW stands for a naturally aspirated 6.3544 Engine. TU stands for a turbocharged 6.3544 engine. The next five characters are the parts list number. The next single letter is the country of origin. The next set of numbers is the production serial number, and the last letter is the year of manufacture.Fuel System
BASIC FUEL SYSTEM DIAGRAM 1. Fuel injectors (atomisers).2. Fuel return line from injectors.3. Cold start heater (thermostart).4. Fuel return line from secondary filters.5. High pressure fuel lines.6. Fuel injection pump.7. Fuel return line from injection pump.8. Fuel transfer pump.9. Fuel supply line to injection pump.10. Secondary filters.When the engine is turning, fuel is pulled from the fuel tank through a water separator by fuel transfer pump (8). When the fuel goes through the water separator, any water in the fuel will go to the bottom of the bowl. The fuel transfer pump sends the fuel at a low pressure to secondary filters (10). From the secondary filters, the fuel goes through line (9) to fuel injection pump (6). The fuel injection pump sends high pressure fuel through lines (5) to each fuel injector (1), and the fuel injector sprays fuel into the cylinder. Fuel not used by the injection pump goes through line (7) back to the inlet side of secondary filters (10).Leakage from the fuel injectors flows through line (2) to the top of secondary filters (10) and back to the fuel tank.The fuel injection pump needs fuel for lubrication. The precision parts of the pump are easily damaged. For this reason, the engine must NOT be started until the injection pump is full of fuel that is free of air.The system must be primed any time any part of the system is drained of fuel. For example, when the secondary filters are changed or a fuel line is removed, the inspection cover on the fuel injection pump is removed to check timing, or the injection pump is removed for service or repair, the fuel system must be primed (air removed).
FUEL SYSTEM COMPONENTS (SIDE VIEW)
1. Fuel injector. 5. High pressure fuel lines. 6. Fuel injection pump. 7. Fuel return line from fuel injection pump. 9. Fuel supply line to fuel injection pump.
FUEL SYSTEM COMPONENTS (TOP VIEW)
1. Fuel injector. 2. Fuel return line from injectors. 3. Cold start heater (thermostart). 10. Secondary filters.There is a small screen in fuel transfer pump (8). The pump also has a lever to prime the fuel system (remove the air). The orifice in the cover of secondary filters (10), to release air in the system, is in the inlet side of the filters. The orifice is connected to the fuel tank by return line (4).Cold start heater (3) is installed in the inlet manifold. It is controlled by the ignition switch.
Unless there is fuel flow through the valve body of the cold start heater, the unit will be destroyed. The fuel supply line to it must also be free of air, or damage will result. A cold start heater that's damaged will let fuel drain into the inlet manifold when the engine is running. This will cause exhaust smoke.
Fuel Injector Operation
FUEL INJECTOR
1. Outlet for return fuel (leakage). 2. Cap nut. 3. Fuel inlet line from injection pump. 4. Lift adjusting screw. 5. Compression spring. 6. Body. 7. Valve spindle. 8. Nozzle cap nut. 9. Nozzle needle valve. 10. Nozzle. 11. Orifices (four).Fuel, under high pressure from the fuel injection pump, goes through the hole in fuel inlet (3). The fuel then goes around nozzle needle valve (9), fills the inside of nozzle (10) with fuel and pushes against valve (9) and compression spring (5). When the force made by the pressure of the fuel is more than the force of spring (5), valve (9) will lift. When needle valve (9) lifts, fuel under high pressure will go through four orifices (11) into the cylinder. When the fuel is sent to the cylinder, the force made by the pressure of the fuel in the nozzle body will become less. The force of spring (5) will then be more than the force of the pressure of the fuel in the nozzle body. Valve (9) will move quickly to the closed position.
FUEL INJECTOR
2. Cap nut. 6. Body. 8. Nozzle cap nut. 10. Nozzle.Needle valve (9) is a close fit with the inside of the nozzle and makes a positive seal for the valve.When the fuel is sent to the cylinder, a small quantity of fuel will leak by the valve guide. This fuel gives lubrication to the moving parts of the fuel injection nozzle. This fuel then goes through a leak-off passage in cap nut (2) to outlet (1) and is returned to the fuel tank.Fuel Injection Pump
The fuel injection pump is a totally enclosed and pressurized system. The pump is of the single cylinder opposed plunger type and uses inlet metering at low pressure to control the volume of the high pressure fuel injection charges.A rotor turns inside the closely fit stationary cylindrical body and functions as a pump and distributor rotor. The opposed pump plungers carried in the rotor have displacement outward on the fill stroke because of internal fuel pressure. The pump plungers are driven inward on the pump stroke