Chery Tiggo T11 LHD. Manual — part 50

Chery T11 Service Manual Electric Injection System

13

The fuel pump lubricating and cooling are

implemented with the help of the gasoline in

the fuel tank.

The fuel tank of this vehicle is a saddle-shaped

tank, with two fuel pump openings.

Decompression pressure: < 900 kPa

Operating voltage: 8 to 16 V

Fuel pump resistance: < 130 Ω

The injection pump in the reserve tank is used

to pump the fuel return to the main fuel tank.

Troubleshooting: The fuel pump failures are

generally

the

fuel

pressure

shortage,

non-pumping and etc. During the period of

troubleshooting, examine the fuel pressure of

the system is within the specified range, and

also examine the leakage of pipeline.

In addition, both the positive and the negative

pressure will make influence on the fuel

system.

8. Electromagnetic Injector (INJ)

Application: MT 20U employs the sequential fuel

injection technology. The sequential injection

signals are provided by the intake pressure sensor

(TEMP). If the TEMP is damaged, the mode of

grouping injection is applied to control the fuel

injection in accordance with the ignition sequence.

Based on the instructions from ECU, the fuel

injector injects the fuel within the specified time,

offers engine the fuel and atomizes them.

Structure and Principle: The ECU emits the

electrical pulse to the injector coil, which forms

the magnetic field force. When the magnetic field

force rises up enough to conquer the resultant force

of the return spring pressure, gravity force of

needle valve and frictional force, the needle valve

starts to rise, and the fuel injection process begins.

When the fuel injection pulse ends, the pressure of

return spring enable the needle valve to be closed

again.

Profile of a electromagnetic injector

T11 Fuel Injector Group

Circuit diagram of electromagnetic fuel

injector

Main Relay

Chery T11 Service Manual Electric Injection System

14

Installation Hint: For the specified fuel

injector, the specified plugs must be applied,

without mixing.

To install the injector conveniently, it is

recommended to apply the un-silicon clean

engine oil on the surface of upper O-ring which

connects to the fuel distribution pipe. Pay

attention not to let the oil contaminate the

interior of fuel injector and its injection hole.

During installation, the lower opening of

injector must be sealed at all times, otherwise,

it is possible to cause the intake system air leak.

Install the fuel injector on the fuel injector

mount in the direction vertical to the injector

mount, and then use the clips to fix the injector

on the fuel injector mount.

CAUTION: For the vehicle out of service for a

long term, due to the adhesive of gasoline in the

injector, the vehicle will be difficult to start up

after a long time of outofcommission. In this

case, please examine carefully whether the fuel

injector is adhesive.

Trouble Diagnosis: MT 20U electronic fuel

injection system doesn’t conduct the trouble

diagnosis on the fuel injector, but conducts the

trouble diagnosis on the fuel injector driver.

When there is short circuit between the fuel

injector driver and the battery, or short or open

circuit between the fuel injector driver and the

earth, or the fuel injector driver is overloaded,

its fault flag is set. In this case, the oxygen

sensor closed-loop control and its self-learning

precontrol shall be switched off, and the last

self-learning data is effective. The fault flag

resets after the completion of troubleshooting.

Pin:

1) No 1 for No 1 cylinder fuel injector control

electrode (to ECU 55#);

2) No 2 for No 2 cylinder fuel injector control

electrode (to ECU 70#);

3) No 3 for No 3 cylinder fuel injector control

electrode (to ECU 56#);

4) No 4 for No 4 cylinder fuel injector control

electrode (to ECU 71#).

The other wires of four injectors connect

together each other, power supply of which is

provided through the main relay of engine. The

ECU controls the injector earth.

Troubleshooting: Due to the long period of

engine operation, it generally results the bad

fuel injection and atomization of fuel nozzle.

Regularly rinse the fuel nozzle.

The short or open circuit of the internal circuit

of fuel nozzle will also cause the fuel injection

system failure.

The short or open circuit of the system wires

will cause the injection system failure.

Due to the long period of use of unqualified

fuel, the fuel will adhesive to the injection hole

of nozzle, which easily cause the fault of

unstable idle.

Operating pressure: 350 kPa

Resistance of fuel injector: 11 to 16Ω

Operating temperature: -40 to 130℃

Chery T11 Service Manual Electric Injection System

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9. Idle Actuator Stepper Motor (IDLE)

Function: Control the air flow area of bypass

channel in the throttle valve, and further control

the air intake quantity of the engine. Based on the

signals from all sensors, the ECU can control the

engine speed within the target speed range which

can be calibrated in accordance with the coolant

temperature.

Structure and Principle: In fact, a stepper motor

is a micro-motor. Since the coil of motor passes

through different directional currents, the motor

will rotate in different direction. The rotary shaft of

the motor will drive the threaded spindle

movement and indirectly control the opening of

the valve. MT 20U emits the digital square wave

signal to control the ahead-reverse rotation and

further control the stroke of the stepper motor.

Trouble Diagnosis: The ECU can monitor the

short or open circuit of two coils of the idle stepper

motor, and light the engine failure lamp when

these troubles occur, which means that the engine

switches to the failure mode.

It also monitors the short or open circuit between

the four wires of sensor and the ECU.

ECU can’t monitor the troubles generated by the

mechanical part of the motor.

Troubleshooting: Examine the short or open

circuit of four wires connection between the

stepper motor and the ECU.

Examine the jamming of the stepper motor.

Examine the short or open circuit inside the

stepper motor.

Disassemble the stepper motor, power on, and

then examine the flexibility of the stepper motor.

The carbon deposit and dirty material in the
intake system will make an influence on the
operating performance of stepper motor.

Resistance of motor coil: 58.3 to 47.7Ω

Operating voltage: 7.5 to 16V

Profile of idle actuator stepper motor

T11 Idle Stepper Motor

Circuit diagram of idle actuator stepper motor

Pin:

1) No 1 (B) for idle actuator stepper motor

control (to ECU 33#);

2) No 2 (A) for idle actuator stepper motor

control (to ECU 34#);

3) No 3 (D) for idle actuator stepper motor

control (to ECU 54#);

4) No 4 (D) for idle actuator stepper motor

control (to ECU 53#);

Air

Idle Control Valve

Throttle Valve Body

Chery T11 Service Manual Electric Injection System

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10. Ignition Coil (COIL)

Function: The ignition coil changes the low

voltage passing through primary winding to the

high voltage through the secondary winding,

creates the sparkle with the help of the ignition

plug discharge to ignite the fuel-air mixture in

the engine.

Structure and Principle: MT 20U adapts the

grouping ignition technology, which, based on

this principle that the mutual inductance of

electromagnetic coils can create higher energy,

controls the power on hours and power off time

of the primary coil. It applies the high voltage

generated in the secondary coil to break down

the ignition plug clearance, create strong

sparkle and ignite the mixture. Due to there are

many ionized airs, lower electrical resistance

during the stroke of engine exhaust, only lowest

voltage is required to break down the ignition

plug clearance. Thus, this system employs the

grouping ignition technology, which can’t waste

the energy and may save cost.

Trouble Diagnosis: The ECU doesn’t have the

function to conduct the trouble diagnosis on the

ignition coil. Thus, if the ignition coil fails to

operate, it doesn’t create any fault code. Only

examination of ignition coil resistance is

available to determine the normal operation of

ignition coil. In the normal condition, the

heating value of ignition coil is great during the

operation of the coil, but the over-high

temperature of the ignition coil will result in the

increase of its resistance value, and further

cause the unstable engine operation, automatic

stop operation and other failures. However, the

ECU can monitor the control wires of the

ignition coil:

1) Control wires short circuit to earth;

2) Control wires short circuit to power supply;

3) Control wires open circuit.

Profile of ignition coil

T11 Ignition Coil Group

Circuit diagram of ignition coil

Pin:

1) No 1 (C) for the coil primary winding (to

ECU 32#);

2) No 2 (A) for the coil primary winding (to

ECU 52#);

3) No 3 (B) for the coil power supply (to the

main relay of the system)

Main

Relay

High-Voltage

coil