After the fourth national motorcycle discharge must be applied to the electronic injection technology, compared with the structure of carburetor motorcycle has a big change, once the need for maintenance, the present is bound to be complex pipelines and joints! Many old maintenance masters for this new technology, will also feel at a loss, but if we master some of the basic principles of the new technology, in addition to follow some of the previous diagnostic technology, we can accurately and quickly find out the fault!

（1）, outside and then inside

In the event of an engine failure, the possible fault areas other than the electronic control system should be examined first. In this way, it can avoid a fault that has nothing to do with the electronic control system, but carry out complex and time-consuming and laborious inspection on the sensor, ECU, actuator and circuit of the system, that is, the real fault may be easy to find but cannot be found.

Air intake system, for example, ECU according to the main air flow meter measured air flow or inlet pipe pressure measured intake manifold pressure sensor to control the fuel injection quantity, so the air intake system and untight seal leakage causes engine imbalance, causing unstable idle speed, easy to stall, dynamic performance and acceleration, to the influence degree of the system is much bigger than the carburetor engine.

When the fault of the intake system is diagnosed, the basic diagnosis procedure without electric control components should be checked and eliminated firstly. If the fault is still not eliminated, and it is confirmed that the air intake system has a fault, the air filter should be removed first, visual inspection, to eliminate some general fault factors. The inspection includes the following items:

1. Check the filter element and its surroundings for dirt, impurities or other pollutants, and replace if necessary.

2. Check whether the intake pipe is broken, leaky, aged or crushed.

3. Check whether the wiring harness connecting each sensor to the computer is loose or disconnected, whether the wires are worn or short circuited or open, whether the wires are plugged in place, whether the wires are corroded, etc.

4. Check whether there is any obvious damage to each sensor.

（2）, first simple then complex

Possible fault areas that can be examined in a simple way are examined first. For example, intuitive diagnosis is the most simple, we can use visual inspection methods such as seeing, touching, listening and so on to find out some relatively obvious faults quickly.

If the fault is not found in the visual diagnosis, it should be checked first if it is easier to be checked by means of instruments or other special tools.

（3）, cooked before cooked

Due to the complex structure and working principle of the electronic injection system, different models of the electronic injection system often have great differences, in the inspection and elimination of the fault of the electronic injection system, it is necessary to understand the working principle and structure characteristics of each electronic injection system, refer to the need to repair the detailed technical data.

In addition to the use of different environment and other factors, the engine may be a fault of some assembly or parts of the most common failure, these common fault should be inspected first. If the fault is not found, then examine other possible parts of the fault that are not common.

（4）. Code first

As the electronic injection system is more and more complex, it is more difficult to judge the fault location when the fault occurs. In order to facilitate maintenance, modern motorcycles generally have a fault diagnosis function. When the eAF engine is running, after the fault is detected by the fault diagnosis system, the fault is stored in the memory of the computer in the form of code, and at the same time, an alarm is given to the rider through the warning light.

Repair, therefore, should be preferred by means of fault diagnosis of ECU interface (socket), according to the specific procedure using artificial jumper or using fault diagnosis, fault code from the ECU memory out, and, in the form of light or directly by the diagnostic instrument display screen is displayed in digital form, thereby helping to maintenance personnel to quickly judge fault type and scope of correctly.

After the fault indicated by the fault code has been eliminated, if the engine fault phenomenon has not been eliminated or the trouble-free code output has begun, the possible fault parts of the engine are checked.

After troubleshooting, the fault code stored in the ECU memory is also cleared by manual method or with the help of a diagnostic instrument, in accordance with a specific procedure, in order to record and store new fault codes. If the old fault code is not cleared, when the engine fails again, THE ECU outputs both the old and the new fault codes, so that the maintenance personnel do not know which is the real fault of the engine and which is the fault that has been eliminated before, which causes the confusion of the old and new fault codes and brings difficulties to the maintenance.

（5）Think before you act

As we all know, random demolition and blind touch can only turn a small fault into a big fault, or even cause irreparable situation, bring undue losses. Therefore, it is necessary to first analyze the engine failure phenomenon, understand the possible reasons for the failure, and then conduct fault inspection.

Only in this way can the blindness of fault inspection be avoided: neither will invalid inspection be done to the parts that have nothing to do with the phenomenon of fault, but also can avoid missing inspection of some relevant parts and can't quickly eliminate the fault.

（6）. Prepare before use

The performance of some parts of the electronic injection system, the electrical circuit is normal or not, often to its voltage or resistance and other parameters to judge. Without such data, system failure checks would be difficult and replacement methods would often have to be adopted, which sometimes resulted in steep maintenance costs and labor costs. Therefore, in the maintenance, should be ready to repair the model of the relevant maintenance data.

In addition to collecting and sorting out the maintenance data from maintenance manuals and professional books and periodicals, another effective way is to use trouble-free vehicles to measure the relevant parameters of their system and record them down as the test and comparison parameters of the same type of vehicles for future maintenance. If we pay attention to this work, it will bring convenience to the fault inspection of the electronic injection system.

Special attention: the failure of the eJECTION engine is not always due to the Ejection system. If an engine fault is found and the fault warning light is not on (failure code is not shown), in most cases, the fault may not be related to the EJET system. In this case, the fault should be checked according to the basic diagnostic procedure as if the engine were not equipped with the EJET system.

Otherwise, it may encounter a fault that has nothing to do with the ELECTRONIC injection system, but it takes a lot of time to check the sensor, actuator and circuit of the electronic injection system, while the real fault is not found.