Chery A11. Manual - part 167

 

Maintenance Manual for Chery·Windcloud          

Marelli EFI System 

 

 

with fuel return interceptor to ensure no fuel 
return, and check if fuel pressure is formed 
rapidly.  

No Repair/ 

replace 

injector or fuel pipe 

Yes 

Repair or replace fuel 
inlet pipe 

14 

Check if leakage or clogging occurs in fuel inlet 
pipe 
 

No 

Replace fuel pump 

Yes 

Repair or replace fuel 
return pipe 

15 

Check if fuel return pipe is blocked up or bent. 
 

No Replace 

pressure 

regulator 

Yes 

Go to next step 

16 

Check if data of intake manifold absolute 
pressure and intake air temperature sensor is 
normal.  

No Replace 

sensor 

Yes 

Go to next step 

17 
 

Check if spark plug, high voltage line and 
ignition coil are in good condition.   

No 

Replace or adjust 

Yes Check 

air 

conditioning system 

18 

Check if caused by air conditioning system.   

No Replace 

ECU 

 
15). Air conditioning system failure

 

Yes 

Go to next step 

1 

Check if there is enough refrigerant in system, 
and if air conditioning belt, air conditioning 
clutch and pressure switch are working in good 
condition.  

No Troubleshooting 

Yes Eliminate 

failure 

displayed 

2 

Make engine run at idle speed, and switch on air 
conditioning switch. Check with scanner to see 
if failure of air-conditioning thermal resistor 
occurs.  

No 

Go to next step 

Yes   

Go to next step 

3 

Turn on air conditioning switch, connect 
commutator between ECU and wire harness, 
and then measure to see if there is signal input 
on air conditioning switch, air conditioning 
pressure of ECU.   

No 

Check wire harness 
 

Yes  

Replace  bulb  or 
repair wire harness 

4 

In case low-level control is adopted, check if 
air-conditionor still works when it is OFF.   

No 

Go to next step 

Yes  

Repair 

air 

conditioning relay 
and wire harness 

5 

Check if there is low-level output at ground 
terminal of pull-up coil of ECU air conditioning 
relay. 

No Replace 

ECU 

 

56

 

Maintenance Manual for Chery·Windcloud          

Marelli EFI System 

 

8. System Maintenance Safety Precautions 

1). Diagnostic maintenance safety precautions for EFI system 
(1). Controller dismounting requirement 
Controller shall be dismounted before electric welding or stoving varnish;   
When dismounting controller, ignition switch shall be pulled to OFF so as to avoid damage;   
Do not pull out power line from accumulator when engine is in operation or electric system is 
in use (with surge voltage);  
Do not use heavy current of charger to start engine;   
Caution: the ambient temperature of controller shall not exceed 80°

 

(2). Cleaning requirement: The following regulations shall be observed in a serious manner 
before operating on fuel supply system and fuel injection system:   
Dismounted parts shall be placed at clean site and well-covered with silk as appropriate 
instead of fiber-falling cloth;   
(3). Various wire harnesses and wire harness of scanner shall be unplugged and plugged after 
ignition switch is OFF;   
When measuring voltage or grounding on electronic control system, correct connection shall 
be ensured;   
Diagnostic and self-learning information stored may be lost due to power line pulled down or 
controller connector of wire harness unplugged from accumulator.   
(4). Precautions on fuel supply system maintenance 
When disassembling and assembling fuel pump on the fuel tank filled or partly filled with 
fuel, pay attention to the following:   
Before operation, device well enough to absorb leaking gasoline shall be installed 
neighboring fuel tank opening.   
Avoid direct contact of skin with gasoline.     
Before loosening a connection, make sure to clean thoroughly the part and its surroundings;   
In order to avoid fuel splash of loosen part, duster cloth shall be laid on the surroundings of 
the connection;   
If maintenance is not carried out immediately on unclosed part, the said part shall be covered 
or sealed carefully;   
Fittings shall be taken out from package prior to assembling, no fittings without package are 
allowed to be used;   
When installing injector, make sure not to damage O- ring; in order to facilitate assembling, 
apply small quantity of lubrication oil on the said ring;   
Do not use compressed air and do not move vehicle as far as possible after system is opened.   
2) Safety measures 
In order to avoid personnel injury as well as fuel injection and ignition device damage, pay 
attention to the following:   
(1). If engine is in operation or at starting rotating speed, do not touch or unplug ignition wire 
harness;  
If engine is to be droven by starting motor instead of starting itself, for example on occasion 
of compression pressure examination, wire harness plugs shall be pulled out from Hall sensor 
and crankshaft position sensor. 

 

 

57

 

Maintenance Manual for Chery·Windcloud          

Marelli EFI System 

 

 

Caution: the ECU plug of A-series engine is liable to have problem of interior looseness, 
in case such problem occurs while line, sensors and control unit are all normal, ECU 
wire harness shall be replaced or ECU plug shall be disposed of.   

 
 
 
 

 

58

 

Maintenance Manual for Chery·Windcloud   

MOTOROLA EFI System

 

 

1

Chapter One: Operating Principle for EFI 
Control and Execute Components 
 
1. Intake Pressure and Intake Air 
Temperature Sensor 

MOTOROLA EFI system adopts air 

measurement method of velocity and density to 

measure the air capacity entering engine so as 

to control fuel injection pulse width further 

accurately control engine power output.   

 

Pressure-sensitive element inside intake 
pressure sensor detects pressure signal on 

intake manifold via sensing hole connecting 

intake manifold, within which is a 

pressure-sensitive element, the resistance value 

varies with the changing pressure, after 

conversion of this signal, it will become an 

important parameter for the control of engine 

performance.  

 
Intake air temperature sensing element is a 

resistor of negative temperature coefficient 

(NTC), which is similar to water temperature 

sensor with resistance value decreasing with 

the increasing of intake air temperature. And 

engine ECU monitors the variation of intake air 

temperature via a comparison circuit inside.   

 

Failure diagnosis:   

Short circuit occurs on the sensor line circuit;   

Open circuit occurs on the sensor line circuit;   

Sensor detects intake pressure to be over upper 

limit;  

Sensor detects intake pressure to be over lower 

limit;  

 

Installation: to be installed on pressurizer.   
 
 

Troubleshooting: mainly check if there is 

short circuit or open circuit on the connection 

between 4 lines on senosr and ECU.   

If sensor’s sensing hole is pluged up.   

If there is short circuit, open circuit or 

grounding between sensor wire harnesses.   

 

 

Manifold absolute pressure /intake air temperature sensor 

 

Intake temperature /
pressure sensor

 

 

Circuit diagram of manifold absolute pressure and intake 
air temperature sensor

 

Pins: 1# connects with standard 5V power 

source (connecting ECU B22#); 

2# outputs pressure signal (connecting 

ECU B19#);   

3# sensor ground (connecting ECU 

23#);  

4# outputs temperature signal 

(connecting ECU B18#). 

 

 

Side view of intake pressure and intake air temperature 

sensor