49 

 

No. 029 Hard to stard engine when heating   

Malfunction Cause 

Solution 

Check battery voltage, whether it is normal. If the value is 
too low, shall charge and check charge circuit, as well as 
related components. 

Check starter, and maintain or replace it when starter coil is 
heated and short circuit. 

Low starter speed or sliding 

If motor idles, then the starter flywheel gear and motor gear 
slide when match, which results engine hard to start. 

Electric controlling system 
malfunction 

Connect Geely special decoder to check whether there is 
malfunction code. And inspect again if it shows malfunction 
code. Then check relevant component and circuit according 
to the indication of malfunction code. 

Spark plug malfunction 

Check spark plug electrode clearance and carbon deposit 
condition. Adjust or replace it when necessary. 

Check heating operation, whether there is high voltage 
spark. If not, check engine speed sensor, ignition coil, ECU 
and relating circuit. Maintain or replace them when 
necessary. 

Weak high voltage spark 

Check high voltage spark energy. If it is weak, check ignition 
coil, spark wire resistance. Replace them when abnormal. 

Cooling fluid temperature sensor 
malfunction 

Check cooling fluid temperature sensor. In different 
temperatures, its resistance shall vary according to specified 
standard. Replace it when necessary. 

Injector malfunction 

When heating, the expansion difference of valve seat and 
element   may affect injector pin valve and result valve 
seat and element stuck or leak, which relates with spark 
plug drown and primary fuel pressure lose and cause hardly 
to ignite. Check injector, replace it when necessary. 

Fuel quality problem 

Check fuel, whether it is polluted, or contains other problem. 
It is recommended that customers shall change the gas 
station, where they often attend. 

Engine cylinder, connect rod, 
crankshaft and camshaft bearing fit 
pressure is over normal value 

Engine cylinder, connect rod, crankshaft and camshaft 
bearing fit pressure is over normal value, the expansion 
when heating will result crankshaft stuck. Maintain relating 
part. 

Speed sensor output signal abnormal

Engine speed sensor resistance or output signal and signal 
tooth clearance abnormal, which results improper ECU 
ignition timing, as well as engine hard to start. Shall adjust or 
replace engine speed sensor. 

Air filter blocked 

Clean or replace 

Low fuel pressure 

Check fuel pressure, if it is too low, shall inspect fuel 
pressure controller, electric fuel pump, fuel filter and pipes. 

Intake pressure temperature sensor 
operates abnormally 

Intake pressure temperature sensor is heated, which results 
signal misalignment. 

Hard to start engine 
when heating 

ECU inner malfunction 

The triode in ECU controller is heated, and fails to input or 
output signal normally. Shall replace ECU. 

 

 
 

 

 

50 

 

Intake pressure temperature sensor operates 

abnormally 

ECU inner malfunction 

Low fuel pressure 

Air filter blocked 

Speed sensor output signal abnormal 

Engine fit pressure is over normal value 

Fuel quality problem 

Injector failure 

Cooling fluid temperature sensor failure 

Weak high voltage spark 

Spark plug failure 

Electric controlling system failure 

Low starter speed or sliding 

Hard to stard engine when heating 

Replace 

Check and replace 

Clean 

Check 

Check 

Check 

Check and replace 

Replace 

Clean and replace 

Replace 

Replace 

Replace 

Replace 

Blocked 

Low 

Lack 

Abnormal 

Abnormal 

Abnormal 

Abnormal 

Over fitted 

Abnormal 

Abnormal 

Abnormal 

Abnormal 

Abnormal 

Normal 

Normal 

Normal 

Normal 

Normal 

Normal 

Normal 

Normal 

Normal 

Normal 

Normal 

Normal 

 
 

 

 

51 

 

No. 030 Idle speed unstable   

Malfunction Cause 

Solution 

Improper throttle position sensor 
adjustment 

When idling, the action, such as open AC, operate steering wheel 
or open front lamp, will increase engine load. ECU will add 
injection quantity to remain engine running stably, as well as to 
prevent engine shut-off when engine load increased. Disconnect 
idle speed conducting point, while engine is not running in idle 
condition, determined by ECU, and it will remain injection quantity 
instead of increase it. Therefore, the engine speed remains as 
before, and ECU will adjust idle speed according to the order of 
oxygen sensor mixer. The malfunction is indicated by low engine 
speed when open AC or operate steering wheel in idle condition. 
When the throttle is closed totally, inspect idle switch of throttle 
position sensor by Geely special deNo.r, whether it is normal. 
Adjust or replace it when necessary. 

Idle speed by-pass pipe blocked

Check throttle and idle speed by-pass pipe, whether they are 
blocked. Clean it when necessary to ensure free-flowing air 
intake. 

Idle speed control valve or 
stepping motor malfunction 

According to engine speed, temperature, throttle open degree 
and AC signal etc., ECU will calculate and adjust idle speed 
control valve or stepping motor, as well as by-pass pipe, to 
decrease engine speed. If idle speed control valve delayed or 
stuck, as well as in the case of throttle malposition etc., ECU will 
fail to implement idle speed adjusting correctly, which results idle 
speed unstable. Shall clean or replace relating parts, sc. replace 
idle speed control valve and implement self-adaption on idle 
speed control valve or stepping motor by deNo.r, series Geely, 
when necessary. 

Electric controlling system 
malfunction 

Connect Geely special decoder to check whether there is 
malfunction code. And inspect again if it shows malfunction code. 
Then check relevant component and circuit according to the 
indication of malfunction code.   

Engine idle speed 
unstable 

Individual cylinder fails to work 

Check operating condition of each cylinder, whether there is 
individual cylinder, which operating abnormal. Particularly the 
spark plug, spark wire, cylinder pressure etc. Maintain or replace 
then when malfunction cause was found. 

 

 
 

 

 

52 

 

Intake pipe leak 

Intake pipe leaking and results incorrect flow rate decision on 
ECU, which will cause unstable idle speed. Check leaking 
position, particularly intake manifold gasket, injector seal ring, 
vacuum pipe and connector etc. 

It has not implement 
self-adaption, after engine ECU 
or battery was replaced. 

In case of replacing engine ECU, battery or disconnect battery 
power for a long time, it shall implement self-adaption according 
to Geely engine self-adaption procedure. 

Generator voltage abnormal 

Check running engine, whether the output voltage of generator is 
in normal value. If it is abnormal and results unstable idle speed, 
then check generator and relating circuit and parts. Maintain or 
replace them when necessary. 

Injector leak or block 

If the injector is leaking or blocked, and fails to inject according to 
ECU order, which results improper mixure gas viscosity, as well 
as individual cylinder operating abnormal and unstable idle 
speed, then shall replace the injector. 

Exhaust system blocked 

Gum deposit, carbon deposit, broken or such problems in 3-way 
catalytic converter result partly or random blockage, which will 
increase the backpressure when exhausting, as well as low 
vacuum of intake pipe, which results abnormal engine exhaust 
and intake performance, that relating with cylinder operating 
performance directly. Replace 3-way catalytic converter. 

Improper stepping motor gasket 
thickness 

Often appears on vehicle MR7131A, stepping motor gasket is too 
thin caused by manufacture process, and results motor operating 
abnormal. Exclude the malfunction by replacing gasket. 

Intake temperature sensor 
malfunction 

Check sensor data and voltage, replace it when necessary. 

Low fuel pressure 

Measure fuel pressure, check electric fuel pump, pipes and circuit 
when it is lower than normal value. Maintain or replace them when 
necessary. 

Improper spark plug and ignition 
advance angle, which results 
unstable idle speed 

Check spark wire cross firing condition, as well as ignition timing. 
Adjust or replace it when necessary. 

Engine bracket cracked 

Check vehicle, whether there is any sign of accident. Engine 
bracket cracked will cause engine vibration, and unstable idle 
speed. 

Oxygen sensor malfunction 

Check oxygen sensor signal, replace it when necessary. 

 

Canister valve malfunction 

Check canister control valve, replace it when necessary.