Sym Citycom.300i, Service Manual

Page: 17 / 270

1. GENERAL INFORMATION
1-12
Troubles Diagnosis (Electronic Fuel Injection System)
A. Engine cannot be started or difficult to be started
To this chapter contents
Check and adjustment Fault condition Probable causes
cylinder compression pressure normal
Low compression
pressure or no pressure
Re-start by following the
starting procedures
No ignition There are some signs of
ignition, but engine can
not be started
Remove the spark plug
again and check it.
Dry spark plug Wet spark plug
1. Fuel injector Defile or blocked
2. Malfunction of throttle valve operation
3. Malfunction of a djust and press the valve
Press the fuel sprayer feed pipe and
confirm whether there is petrol in the
feed pipe
The petrol amount of the fuel
injector is supplied with
sufficiently
Have not supplied with the
fuel for fuel injector
1. Check the fuel amount in the fuel tank
2. Check the supply of the fuel, gasoline
hose and the vacuum tube are blocked or
not.
3. Malfunction of fuel pump relay or wiring
badly
4. Relay damage of the fuel pump or wiring
badly
5. E.E.C system tube are blocked
6. Malfunction of fuel pump
Piston ring seized
Malfunction of cylinder valves
Worn cylinder and piston ring
Cylinder gasket leak
Sand hole in compression parts
1. Malfunction of throttle valve operation
2. Air sucked into intake manifold
3. Incorrect ignition timing
Remove spark plug, install it into
spark plug cap, and perform a
spark test against engine ground.
Perform cylinder compression
pressure test.
Check if sparks Week sparks or no spark
at all
1. Malfunction of spark plug.
2. Defile of spark plug
3. Malfunction of ECU.
4. Malfunction of the AC generator .
5. Ignition coil is in open or short circuit
6. Ignition coil leads open or short circuit
7.
Malfunction of main switch