Foton Series Light Bus. Instruction — part 7

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Figure 3-54 Check Water Pump

Figure 3-55 Check Silicon Oil Fan Clutch

3.7 Starting system

See figure 3-56 for the starting system of BJ491EQ1 multi point electronic fuel injection gasoline engine.

Figure 3-56 Starting System of Gasoline Engine

Ignition switch

Fuse

Starter

Battery

Terminal 30

Terminal 50

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3.7.1 Attraction test for starter

Disconnect excitation coil from C terminal (see Figure 3-57); connect the battery to solenoid, the pinion should

extend out at the moment. If the pinion does not act, replace the solenoid assembly.

Figure 3-57 Attraction Test for Starter

3.7.2 Maintenance test for starter

As per procedures, when the pinion is in extended position, disconnect negative lead and the pinion should

still be in extended out position. If the pinion retracts, replace solenoid assembly (see Figure 3-58).

Figure 3-58 Maintenance Test for Starter

3.7.3 Check retraction of starter pinion

As shown in Figure 3-59, disconnect negative lead from the solenoid switch body, and the pinion should

retract inwards. If the pinion does not retract, replace the solenoid switch assembly.

Terminal C

Terminal 50

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Figure 3-59 Check retraction of Starter Pinion

3.7.4 No-load performance test for starter

As shown in Figure 3-60, connect battery and an vlotage meter, and the pinion should extend out. Check if

the starter rotates freely and stably. Check the current, the value should be less than 90A.

Figure 3-60 No-Load Performance Test for Starter

3.8 Charging system

Model 65A/90A alternator with regulator is used in BJ491EQ1 engine’s charging system. Its connection is as

shown in Figure 3-61.

3.8.1

Check alternator connection for any abnormal noise during engine running. Dismantle to check if any.

● Warning: Never connect or disconnect wiring during engine running to avoid accident.

3.8.2

Check charging indicator lamp circuit. Start the engine and shut it down after it has warmed up. Turn off

all electrical accessories. Turn the ignition switch to “ON”, the charging indicator lamp should lit then.

Terminal 50

Terminal 30

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Figure 3-61 Charging System Circuit

The charging indicator lamp should extinguis after engine has started. Otherwise check circuit of charging

indicator lamp.

3.9 Crankcase ventilation

BJ491EQ1 multi point electronic fuel injection gasoline engine is equipped with positive crankcase

ventilation device, which sucks the exhaust gas leaking into the crankcase to intake manifold and then into the

combustion chamber (via vent valve) to burn again. This design tends to protect oil from contaminatded by fuel,

and protect component surface from corrosion due to anhydride formed from exhaust gas and water vapor.

Therefore, never remove the crankcase ventilation device.

The crankcase ventilation system is mainly composed of the positive crankcase ventilation device (PCV) that

is installed on the cylinder head cover, a vent pipe that connects vent valve to intake pipe, and a short pipe that

connects valve cover to air filter pipe.

● Note: During operation, be sure to prevent the vent valve from being clogged. No damage and gas leak on

connecting hose are allowed.

3.10 Clutch

BJ491EQ1 multi point electronic fuel injection gasoline engine adopts diaphragm spring clutch.

3.10.1

Check driven plate of clutch for wear or damage. Measure the depth of rivet head in friction plate. The

depth should not be less than 0.3mm, otherwise replace the driven plate (see Figure 3-62).

If necessary, replace plate and cover assembly of a clutch.

3.10.2

Check for run-out tolerance on the edge of driven plate (see Figure 3-63). The maximum run-out

tolerance is 0.8mm. If it exceeds this value, replace the driven plate.

3.10.3

Check diaphragm spring for wear. As shown in Figure 3-64, measure depth and width of wear on

diaphragm spring with a caliper. The maximum value: depth 0.6mm, width 5.0mm.

Fuse (5A)

Soft
connection
of battery

Fuse box

Charging
indicator lamp

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Figure 3-62 Check Driven Plate of Clutch

Figure 3-63 Check Run-out Tolerance of Clutch Driven Plate

Figure 3-64 Measure Wear on Diaphragm Spring

3.10.4

Installation of clutch: use the tools same as that used on inputshaft of transmission to install the clutch

driven plate onto flywheel. Align the mark on clutch housing with the mark at outer edge of flywheel, and then

evenly tighten the bolts. The tightening torque is 28~35N·m (see Figure 3-65, Figure 3-66).

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Figure 3-65 Installation of Clutch

Figure 3-66 Installation of Clutch

Check alignment of diaphragm spring end with a dial indicator. The maximum unflatness is 0.5mm. Adjust it

if the unflatness is too high.

● Note: Be careful when to repair clutch parts. Clutch parts contain asbestos fiber, excessive inhalation of

this fiber may cause serious harm to human body. Therefore, always wear a mask during service. Do not use

compressed air and dry brush to clean clutch parts, use special vacuum cleaner for asbestos fiber cleaning . Do not

use sand paper to grind the driven plate in case of harmful dust. If the friction lining of driven plate is damaged or

blurred, replace with a new driven plate. Collect the dust and dirt containing asbestos fiber into sealed bag or

container to protect you and others.

Special tool

Assembly mark

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Chapter 4 BJ491EQ1 Gasoline Engine

Fuel Injection System

4.1 Introduction of Delphi Electronic Control Fuel Injection (EFI) System

4.1.1 Overview

BJ491EQ1 multi point injection (MPI) gasoline engine adopts Delphi ITMS-6F MPI and direct ignition

technology control. ECM receives the signal from all the sensors like air intake pressure sensor and crankshaft

position sensor, and then calculates the optimal fuel injection quantity and ignition timing according to its internal

preset program. ECM outputs to actuating devices (fuel injector, ignition coil) will finally realize the gasoline

engine control functions like fuel injection, ignition and idle speed etc.

EFI system is mainly composed of sensors, control component, actuating components and cables that connect

all the components. Electronic control system composition of BJ491EQ1 MPI gasoline engine please see figure

4-1.

4.1.2 Power Supply of EFI System

EFI system adopts 12V DC power supply. The current from battery enters EFI system and ECM through

different circuits: one entering system through ignition switch is the main power supply; the other one entering

ECM directly through fuse supplies UPS to EFI system.

4.1.3 Fuel Injection System

Fuel supply of EFI system adopts close loop control multi-point group injection device.

Figure 4-1 BJ491EQ1 MPI Gasoline Engine EFI System Composition

Signal input

Crankshaft position sensor

Air intake manifold absolute

pressure sensor

Communication interface

Gasoline engine failure

indicator

Air conditioner

compressor

Canister evaporator

Idle speed air control

valve

Fuel pump relay

Ignition timing

Fuel injector

Control output

System control

Ignition energy

Fuel pressure

Fuel depurate

Three-way catalytic

converter

Coolant temperature sensor

Intake manifold temperature

Oxygen sensor

Voltage signal

Air conditioner on/off request

Air conditioner load signal

Throttle position sensor

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“Close loop control” refers to that ECM corrects and offsets in real time the fuel supply to improve three way

catalytic converter performance. ECM uses the actual air fuel ratio from oxygen sensor when the gasoline engine

is working.

“Group injection” refers to that gasoline engine cylinders are divided into two groups: 1-4 and 2-3; fuel

injector controlled by ECM will inject at air inlet port of certain group when this cylinder group reach to the

bottom dead center, and the cylinders at air intake stroke will suck mixed air; for the cylinders at working stroke,

the injected fuel will stay around the air inlet port and mix with air completely; and the fuel quantity needed by

each cylinder is injected at two times.

4.1.4 Fuel Supply System

Electric fuel pump supplies fuel to EFI system. ECM drives fuel pump relay to connect fuel pump power

supply after receiving gasoline engine rotating signal, and fuel pump then begins to supply pressurized fuel to fuel

supplying system. Before receiving the engine’s rotating signal, ECM will not drive fuel pump to work. This

would ensure the safety of fuel system.

4.1.5 Direct Ignition Device

Direct ignition device adopts grouping direct ignition technology (without distributor) that reduces energy

loss ignition system, while increasing the ignition coil secondary voltage and energy output. The secondary
voltage can reach 34KV. ECM controls ignition coil to ignite the corresponding spark plugs in 1-4 and 2-3
cylinder groups. After ECM unit has collected gasoline engine working signals, ignition timing could be
determined based on 1-4 cylinder’s TDC mark on crankshaft pulley (58X gear ring). Electronic fuel injection
system does need any adjustment, and do not need to consider the wear and carbon deposit in distributor system.

4.1.6 Idle Speed Control Device

The idle control system controls on idle speed by installing idle control valve on throttle valve body, so that it can

control the air input. ECM monitors the fluctuation of the engine speed, carries out closed-loop control on the actual idle
speed by adjusting the injection fuel quantity, ignition time and the opening of idle control valve. ECM also adjusts the
idle speed according to the coolant temperature and engine load at idle speed..

4.1.7 Canister Purge Control system

The canister purge control system controls the working time and speed of canister purging through canister

purge solenoid according to engine speed and load, ensuring a ratified fuel evaporation and engine performance.

4.1.8 Close Loop Control Self-learning function

The electronic system has self-learning function on its closed loop control. It can effectively cancel the

manufacturing difference between systems and other concerning mechanical components, improve the integrity of
a complete machine. It could remove the error resulting from wear during practical use.

4.1.9 Fault Diagnosis Communication Device

ECM controls the operation of all system components and carries out real-time inspection. Once any fault

occurs, the fault diagnosis communication system will turn on gasoline engine fault indicator light to warn the
driver to perform repair. Fault indicator light can also flash to indicate the fault codes, so that service technician
can perform emergency diagnoisis.

4.1.10 Air Conditioner Control Device

When turning on the A/C switch, the A/C control system will receive “A/C on request” signal, and make

preparations for A/C loading according to engine condition at the moment. The AC relay connects AC compressor
then. A/C control system could decide whether or not to connect A/C according to its protective need.

4.1.11 Electronic Anti Theft Device

The device is “plug to use” type. If the anti-theft device does not receive the correct code from ignition key,

ECM will control the system not to inject fuel and ignite so as to perform its anti-theft function.

4.1.12 Overflow Fuel Cut off Control

In the event of engine flooding, you can depress acceleration pedal al the way down and start the engine at

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the same time. ECM will stop fuel injection to discharge excessive fuel from running engine.

4.1.13 Deceleration Fuel Cut off Control

During decelerating, ECM will stop fuel supply. It will reduce harmful emission and improve the fuel

economy.

4.1.14 Electronic Fan Control

ECM can control the electronic fan at dual speeds. After-maket users can install another electronic fan to

improve the fuel economy and reduce over-heating.

4.2 Parts and Components of Delphi EFI System

4.2.1 Air Intake Manifold Absolute Pressure Sensor

Intake Manifold Absolute Pressure Sensor (MAP) monitors the intake pressure at the intake manifold. The signal

from the intake manifold absolute pressure sensor will be sent to the ECM, and it will help to decide fuel injection

amount and ignition advanced angle. Intake manifold absolute pressure sensor will be mounted with its end downward

and pressure hole has a 30°angle to avoid condensed liquid on terminal from being left over inside the sensor. (See

Figure 4-3)

Figure 4-3 Installation of Air Intake Manifold Absolute Pressure Sensor

1- Input voltage; 2-Output voltage; 3-Grounding

Intake manifold absolute pressure sensor is composed by one sealed spring diaphragm and one magnetic

core. They are put in the coil precisely. When it senses pressure, it will produce an output signal (0-5V) which is
postive ratio to input pressure

4.2.2 Intake Air Temperature Sensor

Intake temperature sensor measures the intake temperature and send its signal to the ECM to compute the

intake flow. Intake temperature sensor is installed at the front end of intake pipe. It is composed by one thermistor

(fixed in plastic socket) and one plug blade. The resistance of thermostor is negative ratio to temperature (see

Figure 4-1). MAT is shown in Figure 4-4

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Figure 4-4 Intake Air Temperature Sensor

Table 4-1 Thermistor Resistance and Temperature

Temperature

Resistance without load

100℃

178Ω±4.1Ω

128℃

81.65Ω±2.9Ω

4.2.3 Coolant Temperature Sensor

The coolant temperature sensor (CTS) monitors the coolant temperature and send the signal to the ECM. It is

not only used to compute the intake capacity, but also to ensure transient air-fuel ratio and idle rpm as well as

adjust the ignition advanced angle. It is installed on outlet of coolant pipe. It is composed by one thermistor (fixed

in plastic socket) and two plug blades. The resistance of thermostor is negative ratio to temperature. The resistant

is 81.65Ω±2.91Ωat 128℃.. Figure 4-5 shows a CTS.

Figure 4-5 Coolant Temperature Sensor

4.2.4 Crankshaft Position Sensor

The crankshaft position sensor (CPS) measures the engine Rpm and crankshaft turning angle. ECM

determines the ignition advanced angle and fuel injection timing in each cylinder according to the crankshaft
turning angle signal. It is installed on the cap of timing pulley, corresponding to 58X gear ring on pulley. It is
composed of one permanent magnet / coil. While the crankshaft is running, the tooth and notch on gear ring is
passing the sensor at different distances, causing the change of magnetic resistance to produce different output
signals (collected by sensor). The wave pattern of output signal indicates crankshaft turning position. Signal
frequency is positive ratio to crankshaft rotating frequency.

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The connecting wire of crankshaft position sensor has shield wrap, and it connects to the grounding lead to

avoid electromagnetic disturbance. The crankshaft position sensor is shown on Figure 4-6 and the installation

position shown on Figure 4-7. The principle of the crankshaft position sensor is shown on Figure 4-8.

Figure 4-6 Crankshaft Position Sensor

Figure 4-7 Installation Position of Crankshaft Position Sensor and Crankshaft Pulley

1-Crankshaft position sensor; 2-Crankshaft pulley ; A-20th tooth; B-1st tooth

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Figure 4-8 Working Principle of Crankshaft Position Sensor

1-Crankshaft position sensor; 2 -Pulley with teeth; 3-Signal corresponding with gap teeth; 4-Output signal

4.2.5 Oxygen Sensor

The oxygen sensor monitors residual oxygen concentration in exhaust gas. It compares transient air fuel ratio

with theoretical air-fuel ratio, thus ECM could send command fuel injection system to “increase or decrease fuel”

according to OS signal. This would keep engine operating at theoretical air-fuel ratio state.

Oxygen sensor is installed on the exhaust pipe. Oxygen sensor is not allowed to be collided. Protect its tip

from contanmination by oil, detegent, lead, coke or other organic material.

OS working principal: when the temperature is high than 300℃, zirconia can separate the oxygen ion from

the oxygen in the exhaust gas. In such case, different oxygen contents on two sides of sensor would produce

potential difference. In other words, this potential difference would in turn help to figure out oxygen content

difference in two areas (air side and exhaust gas side). The message will be sent to ECM unit, the unit will then

control fuel injecting amount, adjusting air-fuel ratio to the theoretical value as close as possible.

Figure 4-9 Oxygen Sensor

●

Caution: Notice: As lead restrains platinum oxidation. The gasoline with lead will make OS failure

quickly thus deteriorate emission. Therefore, BE491EQ1 gasoline engine can never use lead gasoline.

Oxygen sensor is heated type (see Figure 4-9). The connector pin, lead color and wire connection of oxygen

sensor are shown in table 4-2. Oxygen sensor output signal is shown on Figure 4-10.

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Figure 4-10 Performance Chart of Oxygen Sensor

Table 4-2 Connector pin, Lead Color and Wiring of Oxygen Sensor (also see figure 4-9)

Pin

Lead color

Pin and wiring

A

Dark brown

Oxygen sensor (grounding)

B

Purple

Oxygen sensor (output)

C

Brown

Heater

D

Brown

Heater

4.2.6 Electronic Control Module (ECM)

The ECM is a microprocessor (figure 4-11), composed of the circuit board and software. It processes

signals from various sensors, and judges the working condition of an engine, then sends best ignition and fuel

injecting signals to actuating mechanism, so as to keep the engine in good working condition.

Voltage

Rich mixed air

Lean mixed air

Air fuel ratio

Lean mixed air with too much air and low CO
volume

Ideal mixed air

Rich mixed air with less air and high CO
volume

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Figure 4-11 Electronic Control Module (ECM)

The installation of ECM requires dustproof, waterproof, and good heat dissipation. Its metal case must be

insulated form the vehicle body. There are two 32-pin sockets (see Fig.2-12) on the ECM circuit board, and two

corresponding ECM plugs on the gasoline engine harness. Be ware of the direction when to connect middle

harness ECM plug into the ECM sockets-- red plug to red socket, white plug to white socket. The lock plate of

harness plug should point to the locking projector on ECM socket. Plug in until a clicking sound is heard.

● Note:

(1)

Mistaken plugging in would burn out precious ECM .

(2) Although the ECM is damp-proof, do not use high pressure washer to wash the case.

External view of ECM is shown in Figure 4-11. ECM has two 32-pin socket J1 and J2. J1 is red, J2 is white,

see Figure 4-12.

Figure 4-12 Section View of ECM

4.2.7 Electric Fuel Pump Assembly

The fuel pump is a turbine single line / electrical type, driven by DC 12V. ECM controls the fuel pump through

fuel pump relay. There is a one-way valve at the outlet of fuel pump. While the engine is working, the fuel in the pipe

will not retrun to fuel tank to ensure restarting performance. The fuel pump is installed inside the fuel tank with a

bracket. The fuel inlet /return pipes are far away from high temperature zone such as exhaust pipe. Pipe connectors and

mounting flanges should be tight and sealed. There should be no fuel leakage to avoid fire and other accidents.

(White)

(Red)

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Structure of electric fuel pump is shown in Figure 4-13 and power connection is shown is Figure 4-14.

4.2.8 Fuel Filter and Fuel Supply Pipeline

The fuel filter is mounted on fuel passage between fuel pump and fuel rail. Use electronic fuel injection filter

to ensure filtering result.

Figure 4-13 Electric Fuel Pump

1-Outlet pipe; 2-Fuel return pipe; 3-Flange; 4-Fuel pump; 5-Fuel strainer

Figure 4-14 Electric Fuel Pump power connection

Fuel filter is composed of case and high performance paper element. It is a very important component as

injector is quite sensitive to impurities in fuel passage.

External view of fuel filter is shown in Figure 5-15.

Replace the fuel filter at every 6000km or when pressure in the fuel pipe is less than 300kPa.

Chapter 4 BJ491EQ1 Gasoline Engine Fuel Injection System

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Figure 4-15 External View of Fuel (Gasoline) Filter

4.2.9 Fuel Rail Components

Fuel rail system is composed of injector, fuel rail, fuel pressure regulator, vacuum pipe, fuel return pipe and

inlet pipe. (see Figure 4-16).

4.2.9.1 Fuel Rail Assembly

Fuel rail is composed by guide pipe, pressure regulating compartment, inlet/return pipe and fittings. It is

installed on the air intake pipe. It offers pressure adjusing capacity (hi-pressure fuel) and pipes to each injectors as

well as brackets for injectors.

4.2.9.2 Injector

The fuel injector is installed on the fuel rail. The injector is a electromagnetic switch controlled by ECM

through the injection paulse width signal. Fuel mist will be sprayed to intake valve when injector opens. (figure

4-16).

Figure 4-16 Fuel rail sets

1-Injector; 2-Vacuum air intake pipe; 3-Fuel pressure regulator; 4-Fuel rail; 5-Fuel return pipe; 6- Fuel Inlet pipe

The resistance of fuel injector coil is 12.0Ω±0.4Ω

4.2.9.3 Fuel Pressure Regulator

Fuel pressure regulator is to adjust the fuel pressure in the fuel rail, keeping its difference with that in air

intake pipe at around 300kPa, so as to remove any disturbance caused by these changes as fuel supply rate, fuel

supply of electric fuel pump and air intake vacuum. (See figure 2-17). It is installed on one end of fuel rail. Extra

fuel through the fuel pressure regulator will return to fuel tank through return pipe (see Figure 4-17).

It is assembled on one end of fuel rail. The extra fuel regulated by the regulator will return back to fuel tank

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