
d. Pressure in oil passage is too low;
e. Irrational starting operation.
f. Throttle position sensor is damaged or circuit of throttle position sensor is broken, no signal is returned to ECU.
g. Ignition system fails.
h. Compression pressure of the engine is too low.
(3) Fault diagnosis and elimination
a. Firstly check oil storage in the oil tank, then turn on ignition switch. If the pointer of gasoline gauge does not move or oil
level alarm lamp illuminates, there is no oil in the tank, now fill in oil.
b. Check whether electric petrol pump works or not. Use a lead to make two detection jacks of electric petrol pump shorted,
then turn on the ignition switch, now sound of petrol pump operation should be heard from the port of oil tank; or when you
pinch the oil outlet pipe, you may feel pulsation of oil flow; or dismantle oil return pipe on fuel pressure adjuster, gasoline
should flow out; or if fuel pressure gauge is mounted, it could be determined directly.
If electric petrol pump does not work, firstly check whether main fuse, main relay, fuel pump relay, fuel pump control circuit
and ECU are normal or not. If they are all normal, then check whether circuiter of fuel pump is open-circuited or shorted,
whether check valve is damaged or not, if there is any problem, repair or replace in time.
c. If there is no injection sound in injector, firstly check whether there is fault in the control circuit of injector, use a test lamp
of large impedance to connect the plug of injector harness. Close ignition start switch, if the test lamp illuminates, the
injector must be damaged, replace it; if the test lamp does not illuminate, then check whether main fuse, EFI relay, fuse,
ignition switch and ECU terminal are normal, if not, repair or replace it.
d. If fuel pressure is too low, fuel injection volume must be too small for the engine to start. Now check
whether fuel filter in the oil passage is clogged or not, whether safety valve of fuel pump is damaged, whether fuel pressure
adjuster is started within normal range, otherwise repair or replace it.
e. Generally, electric injection engine adopts “contact” type start engine.
f. Check whether circuit of throttle position sensor (TPS) is broken or not.
g. Firstly check whether there is any fault code, if there is, check according to fault code; if no, check the strength of high
voltage spark, if it is too weak, check whether there is fault in spark plug, high voltage wire, high voltage coil and distributor
cap etc. If any faults are found, repair or replace it.
h. Check compression pressure of the cylinder. Insert compression pressure gauge into the spark plug hole, open the
throttle completely, measure compression pressure while starting the engine. When revolution of the engine is over
250r/min, if compression pressure is less than 980kPa, dismantle the engine, check and eliminate fault.
3. With Ignition Signs, it Still Fails to Start
(1) Symptom of fault:
When starting the engine, the starter could drive engine to rotate normally, there is some ignition signs, but cannot start.
(2) Cause of fault:
a. Ignition advance angle is not good;
b. Ignition sequence is abnormal, there is false fire;
c. High voltage spark is too weak;
d. Fuel pressure is too low;
e. Fuel pressure adjuster leaks;
f. Idle control valve is damaged;
g. Water temperature sensor is damaged;
h. Vacuum pressure sensor fails;
161
Содержание JL481Q
Страница 1: ......
Страница 9: ...5 Fig 3 Components Assembly Drawing of MR479Q MR479QA Engine ...
Страница 10: ...6 Fig 4 MR479Q MR479QA Engine and Its Power System ...
Страница 11: ...7 Fig 5 Assembly Drawing of Engine and Its Auxiliaries MR479Q MR479QA ...
Страница 12: ...8 Fig 6 Electronic Control Fuel Injection System in Engine MR479Q MR479QA ...
Страница 13: ...9 Fig 7 Front view of Engine JL481Q MR481QA ...
Страница 14: ...10 Fig 8 Sectional elevation of Engine JL481Q MR481QA ...
Страница 15: ...11 Fig 9 Electronic Control Fuel Injection System in Engine JL481Q MR481QA ...
Страница 21: ...17 Fig 13 Exterior Feature of JL481Q Engine Power Me N m Torque Pe Kw ge g kwh Fuel Consumption Ratio ...