Transcription

HondaProgrammed Fuel InjectionHow It Works 2006 American Honda Motor Co., Inc. – All rights reserved.

Table of ContentsSection 3 – Programmed Fuel InjectionProgrammed Fuel Injection System Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1Fuel Delivery System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2Fuel Pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2Fuel Pump Control Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2Fuel Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4Fuel Line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4Fuel Injectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5Fuel Pressure Regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7Idle Air Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10VFR800FI Idle Air Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-10GL1800 Idle Air Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12VTX1800 Idle Air Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14Engine Control Module (ECM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15PGM-FI Mixture Control Maps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-15How the Mixture Control Maps Are Used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-16ECM Self-Diagnosis Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-16Throttle Body . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-20ECM Inputs & Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-21Basic ECM Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-22Correction ECM Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-23Control ECM Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-24ECM Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-25Quick Reference: Normal PGM-FI Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3-27Additional PGM-FI Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-28Absolute Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-28Knock Sensor Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-28Emission Control Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-30Catalytic Converters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-30Oxygen Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-31

PROGRAMMED FUEL INJECTIONPROGRAMMED FUEL INJECTIONSYSTEM DIAGRAMProgrammed fuel injection provides each cylinderwith a precise amount of fuel to mix with theincoming air. This results in maximum fueleconomy and performance because eachcylinder is given only the fuel it needs.To further provide for economy and performance,the system has two computer generated maps.One map provides fuel for low speed low loadconditions, and the other map provides fuel forhigh speed high load conditions.The diagram below presents a graphicoverview of the programmed fuel injectionsystem. We'll examine the fuel deliverysystem first and then the engine controlmodule – after a brief look at the idle aircontrols which are not controlled by theECM. Next, we'll check out the basic,correction, and control inputs. And, finally,the ECM control outputs.CRANKSHAFT POSITION SENSORCAMSHAFT POSITION SENSORPROGRAMMED FUEL INJECTION3-1

FUEL DELIVERY SYSTEMFUEL DELIVERY SYSTEMFuel PumpThe fuel pump is located inside the fuel tank andis accessible through the bottom of the tank.Locating the fuel pump in the tank saves spaceon the motorcycle and keeps the pump cooler,preventing vapor lock. It is electrically operatedand gets its power from the battery through a fuelcut relay. The Engine Control Module (ECM)controls the relay in order to operate the fuelpump.The fuel pump operates: for two seconds when the key is firstturned on when the starter is operating when the engine is runningBefore fuel enters the inlet side of the pump, itmust first go through a mesh filter that preventsgrit and rust from entering the pump anddamaging it.Fuel Pump Control CircuitThe ECM controls power to the fuel pump byswitching the fuel cut relay on or off. The main(engine stop) relay supplies power to the fuelpump control (fuel cut) relay. The bank anglesensor controls the operation of the engine cutrelay by completing the ground circuit.NOTICEWhen testing PGM-FI fuel pumps, always disconnect the ECM connector toprevent possible damage to the ECM.3-2PROGRAMMED FUEL INJECTION

The fuel pump consist of an armature that spinsbetween two permanent magnets and turns animpeller. The impeller draws fuel in and throughthe pump body to the discharge port.MAGNETSA check valve in the pump discharge portmaintains residual pressure in the deliverysystem when the engine is turned off and thepump is not operating. Maintaining residual fuelpressure at the injectors aids in quick enginestarting. Fuel sealed in the system can'tevaporate or deteriorate during winter storage.PROGRAMMED FUEL INJECTION3-3

FUEL DELIVERY SYSTEMFuel Pump Control Circuit (cont.)A relief valve is located on the end of the fuelpump. This relief valve will open if the pressureinside the fuel pump becomes too high due to arestricted or blocked fuel line. When it opens, therelief valve sends fuel back into the fuel tankpreventing further pressure build up.Fuel FilterAfter leaving the pump, fuel flows through the fuelfilter. The filter's paper element is fine enough toblock particles that could cause an injectormalfunction, but not so fine that it restricts the flowof fuel.No replacement interval is given. Replace the fuelfilter when fuel flow is less than the service limit.Note:A replaceable fuel filter is not used on all models.Check the Service Manual for the model you areworking on.Fuel LineOn fuel injected models, the high-pressure hosefrom the fuel pump to the injector fuel rail can bedamaged if it is by mishandled by bending orstretching it too much. This damage is internaland you will not be able to see it. When servicingfuel injected models, avoid damaging the highpressure fuel hose. Lift the tank slowly, beingcareful not to overextend the fuel hose.3-4PROGRAMMED FUEL INJECTION

Fuel InjectorsFuel injectors are electrically opened on-offsolenoid valves. They are either fully closed orfully open. The amount of fuel injected isdependent on how long the injector is kept open.This amount of time is referred to as the injectordischarge duration. Each injector is opened by asignal from the ECM. Fuel is only injected when itis needed – during each cylinder's intake stroke.This is referred to as sequential fuel injection.Inside the injector there's a spring-loaded plungerthat closes against a valve seat. Once seated,the flow of fuel is blocked. When the solenoid coilwithin the injector assembly lifts the plunger, thepressurized fuel sprays into the cylinder. Thebattery supplies the power for the solenoid coil.The injector solenoid coils are a switch to groundcircuit. The ECM provides an electrical groundwhen it determines the injector should beopened.The injector tip's opening is designed to provide aspray pattern that atomizes the fuel to help it mixwith the incoming air.PROGRAMMED FUEL INJECTION3-5

FUEL DELIVERY SYSTEMFuel Injectors (cont.)In 2001 a new type of injector was introduced onsome models. This is a multi-outlet design with aball shaped plunger in place of the taperedneedle plunger. Both four and twelve outletinjectors are used in the new Programmed FuelInjection (PGM-FI) models. These provide a finerspray of fuel for better atomization.The choice of injector type is based onperformance, cost and availability at the time ofdevelopment.Injectors can have two types of failures; electricaland mechanical.There are three possible electrical failures for aninjector:Four Outlet Injector High resistance An open A shortSome models detect electrical failure whilerunning. Others detect it only on start up. The MILswitches on and the engine stops when aninjector failure is detected.There are two possible mechanical failures for aninjector: Leaking fuel (partial or complete) Blocked fuel discharge (partial or complete)Twelve Outlet InjectorPossible fuel leakage is indicated by: Dark spark plug color Fuel fouled spark plugsBlocked fuel discharge is indicated by: A cold exhaust pipe on that cylinder3-6PROGRAMMED FUEL INJECTION

Fuel Pressure RegulatorA fuel pressure regulator is used to maintain fuelpressure. The regulator is mounted to the fuel railand has a return line to the fuel tank. Excess fuelin the fuel rail flows back to the tank. Fuelentering the tank from the return line passesthrough a stainless steel wool pad to remove airbubbles.PROGRAMMED FUEL INJECTION3-7

FUEL DELIVERY SYSTEMFuel Pressure Regulator (cont.)To understand the fuel pressure requirements offuel injection systems, start by looking at theconditions at both ends of the injector. The outputend of the injector points into an intake port. Inorder to spray fuel into the intake port thepressure on the supply end of the injector mustbe greater than the intake manifold pressure.When the engine is running, a vacuum exists inthe intake ports. This is measured in inches ormillimeters of Mercury (Hg). A normal motorcycleidle vacuum pressure is about one inch of Hg., or4.9 psi.Fuel pressure is typically in the range of 32 - 50psi. The GL1800, for example, uses a fuelpressure of 50 psi. That is the pressure differencebetween inlet port vacuum pressure and fuelpressure as shown below. The fuel pressure isset at a fixed amount above the inlet port vacuumpressure. Therefore, changes in inlet portvacuum pressure have no effect on the amountof fuel that an injector delivers when it is openedfor a specific amount of time.3-8PROGRAMMED FUEL INJECTION

A spring presses the regulator valve closed andinlet port vacuum pressure pulls the valve open.These two forces balance to give a continuouslychanging fuel pressure that is a specified amountabove inlet port pressure.Note:Some models have a fuel pressure test port,others require a pressure test banjo bolt. Checkthe Service Manual for the vehicle you areworking on.PROGRAMMED FUEL INJECTION3-9

IDLE AIR CONTROLSIDLE AIR CONTROLSLet’s look at three different idle air controlsystems used on PGM-FI models: VFR800FI GL1800 VTX1800VFR800FI Idle Air ControlA starter enrichment valve controls airflow toeach cylinder at idle speeds. The starterenrichment valves allow air to bypass the throttlevalves at idle to keep the engine running andprovide a fast idle for engine warm up. TheVFR800FI is unique because the starterenrichment valves are adjusted to differentvacuum readings to compensate for differencesin exhaust length between cylinders.AIR CLEANER CASESTARTER ENRICHMENT VALVEWhen the starter enrichment valves are open, air flows from the air cleaner case,past each starter enrichment valve into each intake port.3-10PROGRAMMED FUEL INJECTION

Fast idle function is obtained by opening the airvalves further, allowing more air to enter theengine. On '98 and '99 models, a choke leveropens the starter enrichment valves.On 2000 and later models, the starter enrichmentvalves are open a predetermined amount at coldengine condition for fast idle. A thermowaxmechanism is used to automatically close thestarter enrichment valves gradually, based onengine temperature. Engine coolant heats thethermowax pellet, causing it to expand and closethe starter enrichment valves.Starter enrichment valve synchronization isrequired after disassembly of the throttle body, orif the idle becomes rough or uneven. The starterenrichment valve for cylinder 1 is the base and isnon-adjustable. There is no scheduledmaintenance interval for starter enrichmentvalve synchronization.PROGRAMMED FUEL INJECTION3-11

IDLE AIR CONTROLSGL1800 Idle Air ControlThe idle air control (IAC) valve, operated by theECM, controls the volume of air that enters theengine during idle to maintain an even idle speed.It controls idle speed fluctuations and adjusts thebasic idle speed by supplying air to the intakemanifolds according to the: engine coolant temperature alternator load throttle valve positionThe IAC also controls fast idle by providing moreair to the engine during warm up.An electromagnetic coil attracting a permanentmagnet on the end of the IAC shaft rotates theIAC valve shaft. As voltage in theelectromagnetic coil is reversed, the valve rotatesin opposite directions to increase or decreaseidle airflow.TURNCLOCKWISE3-12PROGRAMMED FUEL INJECTIONTURNCOUNTERCLOCKWISE

Two air screws control 5