Table 3Section 2 Removal of the Engine Assembly from the Vehicle1. Avoid petrol overflowing (Disconnect from the fuel tank).
2. Remove the front wheel.Figure 1-5Engine AssemblyRemoval of the Engine Assembly from the Vehicle3-5CO
Normal
Low
HighHC
High
High
HighProblems
Bad idle speed
Bad idle speed
(HC reading fluctuates)
Bad idle speed
(Black smoke exhausts)Causes
1. Ignition fault:
Incorrect ignition timing;
Dirt, short circuit, or incorrect spark plug gap.
2. Incorrect valve gap.
3. Suction and exhaust valve leak.
4. Cylinder leaks.
1. Vacuum leaks.
PCV pipe . manifold;
Idle speed control valve;
Brake booster pipeline.
2. Spark lacks since the mixed gas is too thin.
1. Air filter is blocked.
2. PCV valve is blocked.
3. EFI system fails.
ECU fails.
Pressure regulator of fuel oil is out of order.
Water temperature sensor does not work.
Suction pressure/temperature sensor fails.
Injector fails.
The throttle position sensor fails.3. Discharge the coolant completely.
4. Remove the air filter assembly with hose (see Figure 1-5).
(1) Disconnect the joint of the temperature sensor and the wire
plug.
(2) Disconnect the vent duct from the hose of the air filter.
(3) Release the wire clip bolt on the air filter.
(4) Disconnect the hose of the air filter from the throttle body.
(5) Remove 3 bolts and the air filter assemblies.
5. Remove the battery.
6. Remove the fuel pipe sub-assembly.
7. Disconnect the water pipe; disconnect the water outlet pipe of the
heater from the air conditioner pipe.
8. Release the nut and remove the accelerator control cable. -
1 2 3 45-124replacing air cleaner, always ensure that no dirt enters air duct, never
use ungraded air cleaner.
(2) Simple measuring method:
(Remove joint) turn digital multimeter to ohm position, connect
two meter pens with regulator pin 1, 4 and 2, 3 respectively. Rated
resistance between 1, 4 and between 2, 3 at 20°C should be about
43.2 ohm.
9. Fuel injector
(1) ECU energizes coil of fuel injector to form magnetic field force. When magnetic field force increases to
sufficient to overcome pressure of return spring, gravity of needle valve and resultant force of frictional force,
needle valve begins to rise, oil injection process begins. When oil injection impulse cuts off, pressure of return
spring closes needle valve again.
Symptom
Poor idle speed, poor speedup, failure to start
(difficult to start)Possible cause
Since lack of maintenance, gum builds up in
fuel injector and leads to malfunction
Repair precautions:
1. there are many kinds of fuel injector, their appearance is the same, mountable fuel injector may not be the
exactly suitable one, part number of fuel injector used in repair must be consistent with original fuel injector, wrong
replacement is not permitted;
2. To facilitate installation, it is recommended to apply silicon free clean engine oil on O ring surface at upper
part connecting distributing pipe of fuel oil. Pay attention not to let engine oil contaminate fuel injector inside and
jet orifice;
3. To remove and reinstall fuel injector, O ring must be replaced, here do not damage sealing surface of fuel
injector;
4. if fuel injector has two slots, when mount buckle clamp, pay attention not to clamp in the wrong position,
refer to mounting position of original parts;
5. It is strictly prohibited to remove strainer, clean or replace strainer at discretion; 6. after removal, ensure
cleanness of fuel injector holder, avoid foreign matter ingressing the cylinder.
Simple measuring method:
(Remove joint) turn digital multimeter to ohm position, connect two meter pens with fuel injector pins
respectively, rated resistance at 20°C is 11-17 ohm.
Suggestion: use special cleaning analyzer to conduct thorough cleaning for the fuel injector per 20000km.
10. Electric fuel pump
(1) Fuel pump is a vane pump driven by DC motor, is placed in oil tank, immersed in fuel oil, utilizes fuel oil
for heat dissipation and lubrication. Storage battery supplies power to electric fuel pump via oil pump relay, the
relay switches on electric fuel pump circuit only at the time of startup and during operation of engine. When engine
shuts down due to accident, fuel pump stops running automatically.Symptom
Large running noise, poor speedup, failure to start
(difficult to start)Common cause
1. Gum builds up to form insulating layer;
2. Oil pump bushing is blocked with armature;
3. Fuel level sensor assembly is corroded etc.Engine EFI System-Engine EFI System
