Injector Failure Phenomenon and Good or Bad Detection Method

From: http://www.sinocmpinjector.com

In the process of using the injector, we will encounter many problems. Let us learn and understand the Injector failure phenomenon and good or bad detection method.

Injector Failure Phenomenon:

If the engine fuel system lacks maintenance (regularly clean the injectors), it may cause glue accumulation inside the injector and the valve hole will be blocked or the needle valve stuck.
Blocked injector valve holes will result in the inability to inject fuel (full blockage) or poor injection atomization (partial blockage), and stuck needle valves will cause dripping after injection, resulting in engine idling instability, poor acceleration or difficulty in starting. This phenomenon will also seriously affect the emission performance of the engine.
In addition, the water inlet of the injector connector will cause a short circuit, which will make it impossible to inject fuel. Care must be taken when cleaning. The engine fails to start, the engine runs erratically, and the exhaust gas emits severe black smoke. These are all symptoms of a broken injector.

The main fault types of injectors:

1. The valve hole is blocked and fuel injection or atomization is bad.
2. The needle valve malfunction causes flow error or leakage after injection.
3. Unable to inject fuel due to the open/short circuit of the connector.

Injector performance check method:

 1. Listen to working sound detection:

When the engine is running or starting, check the working sound of the injector with a noise stethoscope or similar tool. The operating sound cycle of the injector changes with engine speed. in case no sound or abnormal sound is heard, check the injector circuit (wiring or connector) or injector.



 

2. Resistance check:

Turn off the ignition switch and disconnect the injector connector. Use a multimeter to measure the resistance between the two terminals of the injector. It should be 12Ω at 20 ° C (68 ° F).





                                                                  3. Flow and leak inspection:

(1) Assemble the injector and transfer tool.
(2) Install a suitable vinyl tube to the injector to prevent fuel from splattering during the injection.
(3) Put the measuring cylinder under the injector.
(4) Run the fuel pump and deliver fuel to the injector.
a. Connect the tester to the DLC and execute the "component test" mode to drive the electric fuel pump to work.
b. Disconnect the fuel pump relay connector, and short the two terminals of the fuel pump relay with the maintenance wire to force drive the electric fuel pump.
(5) Use the accumulator to apply voltage to the injector for 15 seconds, measure the amount of fuel sprayed with a graduated cylinder, and measure 2-3 times per injector. The reference value for fuel injection is approximately 46cc / 15sec. If the measured value clearly exceeds the technical specifications, replace the injector.
(6) Check the leakage of the injector nozzle. Do not run the nozzle during this check (but the fuel pump should work). If the fuel leakage exceeds 1 drop/minute, replace it.

Introduction to the inspection method of the fuel injector

1. When the starter drives the engine to rotate, use a long-handled screwdriver or stethoscope to listen to whether the fuel injector has a "click, click" working sound. , At the same time of auscultation, the method of unplugging and reconnecting the injector harness plug can be used to identify whether the injector is working.
2. If the fuel injector does not work, connect the test lamp to the fuel injector's harness plug before starting the engine. If the test light flashes, the injector control system is working normally and the fault is in the injector. To check the injector, use a multimeter to measure the resistance of the solenoid coil. If the resistance value is normal, it means that the injector is blocked, the needle valve is stuck, etc., the injector should be repaired, cleaned or replaced; if the resistance value is abnormal, the injector must be replaced.
3. If the test light is off, the control system or circuit of the injector is faulty. In this regard, you should first check whether the relevant circuit of the injector is intact, and make sure that the computer is faulty under the condition that the external circuit is good.

Injector maintenance precautions:

1. Using a special cleaning analyzer to thoroughly clean the injectors on a regular basis can greatly improve the life of the injectors, and the power, fuel consumption, and emission performance can be maintained in good condition.
2. The top of the injector uses a rubber seal to connect with the fuel rail to form a reliable pressure fuel seal. The bottom also uses a rubber seal and the engine intake manifold to seal the air. Both of these parts must be replaced when the injector is disassembled.
3. When installing the injector or fuel supply pipe, first lubricate the O-ring with gasoline.
If you want to know more about the injector's failure phenomenon and more ways to check the quality of the injector, please contact us！