Maintenance manual for sunray hfc4da1-2c china-IV diesel engines
101
Chapter IV Engine Diagnosis
Section I. Precautions
1. Removal/Installation Requirements for Electronic Control Unit (ECU):
z Remove the controller before welding or baking finish;
z When removing the controller, turn off the ignition switch and disconnect the battery from the system at the same
time, in order to avoid damaging the ECU.
z It is not allowed to remove power cord from the battery when the engine or the electrical system is working.
z Large-current equipment such as charger is not allowed to be directly connected to the starting motor.
z Note: The ambient temperature of ECU should not be greater than 75 degree.
2. Cleaning Requirements:
Please observe the following rules before the operation of fuel supply system and fuel injection system:
z The removed components should be placed at clean field and properly covered by the cloth other than fiber type
(cotton cloth or gauze cloth)
3. All types of harness connectors and the connector for diagnostic instrument should be
connected and disconnected only when the ignition switch is turned off:
z When measuring the power voltage or ground wire of the ECU, please ensure the wiring sequence and method is
correct.
z Disconnecting the power cord or the ground wire of the battery from the system or removing ECU harness
connector will result in the loss of diagnosis and self-learning information stored in ECU. (If the vehicle model is
different, the time of retaining Pleas of the ECU is also different after the loss of power.)
4. Please pay attention to the following points when maintaining the fuel supply system (fuel
supply pipe, fuel pump and fuel injection system):
z Please be very careful during installation/removal of fuel pump on the fuel tank with fuel.
z Prepare proper materials around the fuel tank opening to absorb a lot of fuel leaked from it timely..
z Avoid the fuel contacting your body.
z Thoroughly clean the part and its surrounding before loosening a connector.
z Please prevent any fuel from splashing from the loose part and place a rug around the connector.
z If the disassembled parts could not be timely repaired or properly treated, store the parts properly.
z Take the spare parts out of the package only when they are needed to be installed. Do not use unpacked spare
parts and the spare parts in severe damaged package
z Do not damage the O-ring of return pipe when assembling fuel injector return pipe. Coat a little diesel oil on the
O-ring for assembling convenience.
z Do not use the compressed air and do not move the vehicle after the fuel supply system is disassembled.
5. Safety Measures
To prevent the maintenance technicians from being injured and the fuel and ECU being damaged, please pay attention
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