Chery Tiggo T11 LHD. Manual — part 49

Chery T11 Service Manual Electric Injection System

9

1) There is the insincere battery voltage;

2) There are some insincere intake manifold

absolute pressure signals;

3) There are some insincere engine coolant

temperature signals;

4) The fuel injector driving level fails.

After the fault flag of the oxygen sensor is set, the

fuel quantitative closed-loop control closes, and

then the basic injection time stored in the ECU is

applied to determine the fuel injection quantity.

Installation Hint: The tightening torque of the

oxygen sensor is 50 to 60 Nm. After the oxygen

sensor is replaced, apply a layer of antirust oil on

the new oxygen sensor to avoid that the sensor is

difficult to be disassembled after rustiness.

Troubleshooting: Mainly examine the good

connection of several wires on the sensor, and the

short or open circuit among them.

The damage of sensor is generally caused due to

the lead or phosphorus poisoning. So, you shall

pay more attention to the fuel quality. At the same

time, the excessive consumption of the engine oil

also easily creates the sensor failure.

During the specified time interval, the number of

the oxygen sensor change shall not be less than the

specified number.

Any connection has four pins:

1) No 1 (A) for the oxygen sensor signal

low level (to ECU 6#);

2) No 2 (B) for the oxygen sensor signal

high level (to ECU 62#);

3) No 3 (C) for the power supply of the

main relay;

4) No 4 (D) for the sensor heater wire

control (to ECU 61#).

Chery T11 Service Manual Electric Injection System

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Rear Oxygen Sensor (RO

2

S)

The structure and detection of the rear oxygen

sensor are similar to the front oxygen sensor,

but the purpose that a vehicle equips with the

front/rear oxygen sensor is considerably

different

Purpose:

Front Oxygen Sensor is mainly used to detect

the oxygen content of the exhaust and further

determine the fuel injection quantity. The

sensor converts the oxygen content of exhaust

after combustion into the electric signal, and

then transmits the signal to the ECU. The ECU

utilizes these signals to control the pulse width

of fuel injection, regulate the air-fuel ratio, and

indirectly control the exhaust emission of the

engine.

Rear Oxygen Sensor is mainly used to detect

the oxygen content of exhaust after the

completion of three-way catalytic conversion.

The sensor converts this signal into the point

signal, and transmits it to the ECU. The ECU

compares the signals from the front and rear

oxygen sensors and then determines the

operation of the three-way catalytic converter.

The

trouble

diagnosis,

troubleshooting,

signal detection and other characteristics of the

rear oxygen sensor are the same as the front

oxygen sensor.

Internal structural diagram of a oxygen sensor

T11 Oxygen Sensor

Circuit diagram of rear oxygen sensor

Any connection has four pins:

1) No 1 (A) for the oxygen sensor signal low

level (to ECU 6#);

2) No 2 (B) for the oxygen sensor signal high

level (to ECU 38#);

3) No 3 (C) for the power supply of the main

relay;

4) No 4 (D) for the sensor heater wire control

(to ECU 64#).

Main Relay

Chery T11 Service Manual Electric Injection System

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6. Electronic Control Unit (ECU)

Application:

An ECU is an electric engine control center based

on the microprocessor, with the sensor signal input

interface and actuator drive circuit. It receives and

processes the engine status signals from any

sensor, and transmits the control signal to the

actuators to enable the engine to operate in

accordance with the preset procedure. It makes the

engine in the optimal condition and ensures the

better dynamics, fuel-effective and emission.

Normal operating voltage: 9 to 16V

Overvoltage protection: +24V/-12V < 60 s

Structure: with the shielded casing and PCB

(Printed Circuit Block). There are a majority of

electronic control units in a circuit board, which is

applicable for the control of electronic fuel

injection system.

Installation: Mounted under the water chute of the

front windscreen with the help of a support and

vehicle computer (ECU). Pay more attention to

waterproof.

Operating temperature: -40℃ to 105℃

Profile of a ECU

Functions:

Multipoint sequential fuel injection system;

Grouping ignition system;

Idle control;

Automatic knock closed-loop control;

Provide sensor with the power supply:

5V/100mA;
λclosed-loop control, with the self-adapting;

Dual oxygen sensors;

Emission canister control;

A/C ECU control;

Engine failure lamp;

Engine speed signal output;

Trouble self-diagnosis, with the flash code

function;

Receive the engine load signal.

Troubleshooting: ECU is an electronic

control unit. Due to its lower fault rate, in

general, it is not recommended to adapt the

ECU replacement to solve all problems.

Carefully examine the faults of the periphery

circuits, sensors and other components,

confirm that there is no fault in the periphery

components, and then it is considered to

replace the ECU.

Chery T11 Service Manual Electric Injection System

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7. Electric Fuel Pump (PUMP)

Application: With the specified fuel pressure and

flow rate, this pump transmits the fuel from the

fuel tank to the engine’s main fuel supply pipe, and

keeps the stable fuel pressure (by the fuel pressure

regulator).

Structure and Principle: The electric fuel pump

consists of the DC motor, vane pump, end cover

which

integrates

with

the

check

valve,

decompression valve and EMI components) and

other elements. The pump is installed coaxially

together with the motor, and sealed in the same

casing. The maximum pressure of the electric fuel

pump outlet depends on the decompression valve,

the range of which is 450 kPa to 650 kPa.

However, the pressure of the whole fuel system

depends on the fuel pressure regulator, and, for the

MT 20U electronic fuel injection system, the

pressure is generally 350 kPa.

CAUTION: In case that the fuel tank of a vehicle

is short or lack of fuel for a long time, the fuel

pump will be difficult to obtain the full lubrication,

which makes the fuel pump sintered. Especially,

for the engine taking CNG and LPG as its fuel, the

fuel tank of this kind of engine is generally in the

state of no fuel or lack fuel for a long time, and its

fuel pump fails to be fully lubricated for a long

time, which result in the damage of fuel pump.

The temperature of fuel makes more influence on

the performance of fuel pump. When the fuel

pump operates at the high temperature for a long

time and the temperature of fuel is greater than the

specified temperature, the fuel pumping pressure

of the fuel pump will drop steeply. Thus, if the

engine fails to start during the period of vehicle

warm up, please carefully examine and confirm

whether

the

high

temperature

operating

performance of the fuel pump is bad.

Profile of a electric fuel pump

Circuit diagram of electric fuel pump

Pin: The electric fuel pump has two pins

which connect to the fuel pump relay. There

are symbols “+” and “-“ stamped on the fuel

pump casing near these two pins, which

means the connection to the positive and

negative electrode respectively.

ECU 46# pin is applied to control the fuel

pump relay.

Main Supply

Dynamic Relay

T11 Fuel Pump Control