General Precautions of EFI System Maintenance
F-104
5. Difficult start of engine at any time with normal rotation speed.
General malfunction Locations: 1. Water-containing Fuel 2. Fuel pump 3. Coolant Temperature Sensor; 4.
Fuel Injector ; 5. Ignition Coil; 6. Throttle Body; 7. Air intake passage; 8. Ignition Timing; 9. Spark Plug; 10.
Mechanical Part of Engine
General Diagnostic Flow:
S/N Operating Steps Test Result Follow-up Step
1
Inspect whether or not air filter is blocked, and whether or not
air leakage exists in air intake passage.
Yes
Air intake
system to be
inspected and
repaired
No Next Step
2
Link up the fuel pressure gauge (the linking point to be on the
front end of the oil inlet pipe for the fuel rail assembly), start
the engine, and examine whether or not the fuel pressure is at
about 400kPa under the idling speed operating condition.
Remove vacuum tube on fuel pressure regulator, verify
whether pressure is about 450kpa.
Yes Next Step
No
Fuel system to
be inspected and
repaired
3
Pull out the cylinder connection from one of the cylinders,
link up the spark plug, cause the sparking-plug electrode to be
about 5mm away from the engine body, start the engine, and
examine whether or not there is blue and white high voltage
flame.
Yes Next Step
No
Ignition system
to be inspected
and repaired
4
Inspect spark plugs of respective cylinders, and observe
whether or not their models and clearances are compliant with
specifications.
Yes Next Step
No
To be adjusted
or replaced
5
Pull off the joint of coolant temperature sensor, start the
engine, and observe whether or not engine is successfully
started at this point.
Yes
Line to be
inspected and
repaired or
sensor to be
replaced
No Next Step
6
Gently push down the throttle, and observe whether or not it
is easily started.
Yes
Throttle valve to
be cleaned
No Next Step
7
Demount the fuel injector, and use special cleaning analyzer
for fuel injector to examine whether or not leakage or
blockage exists.
Yes
Fuel injector in
malfunction to
be replaced
No Next Step
8
Inspect the fuel status, and observe whether or not
malfunction symptom is caused just after fuel has been filled.
Yes
Fuel to be
replaced
No Next Step
9
Inspect the pressure situations of respective engine cylinders,
and observe whether or not pressure deficiency exists with
engine cylinders.
Yes
Mechanical
malfunction of
engine to be
removed
No Next Step
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