Electronic fuel injection (EFI) system is a precise and complex system, and it has a great influence on the performance of engine. Whether ECU, the control circuit, any other sensor or actuator is failed, it will affect the engine, running stability, performance or fuel cost to some extent.
If EFI engine does not work or work normally, it may be caused by the electronic control system or other problem, like mechanical problem. And different models of EFI system often have a big difference, so the extent of difficulty for the fault inspection is also different, then that will also bring certain difficulty to check and eliminate faults.
If we can follow some basic principles of fault diagnosis for the EFI motorcycle accessories, it will be easy to diagnosis and eliminate the failure. The basic principles of fault diagnosis can be summarized as follows:

If there is failure with the engine, first, you need to check the outside of electronic control system. This can avoid some glitches which are caused by something unrelated with electronic control system fault, so you don’t need to check the system of sensors, ECU, actuators or lines which is complex and time-consuming, while finally the real failure may be easier to find but failed to find it.
Let’s take the air intake system as an example. ECU controls the fuel injection quantity according to the air flow measured by air flow meter and intake manifold pressure measured by intake manifold pressure sensor. So the bad sealing of air intake system will cause engine imbalance, unstable idle speed, easy to stall, and dynamic performance and acceleration because worse, which will cause worse influence to the system compared with the carburetor engine.
When diagnosing air intake system failure, you should first check according to the basic diagnostic procedures not installed electronic components, if the failure is not eliminated, then you need to confirm whether the problem is caused by the air intake system, and then remove the air filter, do the visual inspection, and eliminate some general problems.

Check the following items:
(1) Whether there is dirt, impurities, or other contaminants around the air cleaner filter, replace it if necessary.
(2) Whether the air inlet pipe is burst, leak, aging or crushed.
(3) Whether the electric wire connected sensor and computer is loose or disconnected, wires have torn or line is short or open, wire plug is in place, any corrosion and so on.
(4) Whether the sensor is obviously damaged.