Contents: Removal ↡ Installation ↡
Warning! When checking the operation of fuel injectors, never place your hands or any part of your body under the jet of fuel coming out of the injector. Fuel comes out of the injector under high pressure and can penetrate the body through the skin. It is recommended to entrust the work of checking the injectors under pressure to a specialist.
When the engine is running, the fuel injectors wear out and after 100,000 km, it is necessary to repair or replace the fuel injectors. Checking, repairing and calibrating the fuel injectors should be done by a specialist.
To determine a faulty injector, you need to make sure that the engine is in good condition and the compression level is the same in all cylinders.
Start the engine and warm it up to normal operating temperature.
Loosen the fuel line nipple nut on the injector being tested. Note whether the engine speed has changed. Perform the same test at fast idle.
If the fuel injector is in good condition, there will be a clear decrease in engine speed, accompanied by uneven operation. If the injector being tested is faulty, the change in engine speed will be insignificant and will disappear if there was an extraneous knocking noise before.
Removal
Caution: Keep the area clean when working with fuel injectors.
Fuel injector
A – fuel injector; B – gasket; C – high pressure pipeline; D – return fuel line; E – plug
1. Remove the ground cable from the battery.
2. Remove the intake manifold.
3. Clean the area around the fuel injectors and fuel line union nuts (see picture). Loosen the clamp and remove the fuel return hose from the fuel injector.
(Article text obtained from the website: «MercedesMan»)
4. Loosen the union nut securing the high pressure fuel line to the top of the fuel injector.
5. Loosen the union nut securing the high-pressure fuel line to the top of the high-pressure fuel pump. Unscrew the union nuts and remove the high-pressure line. Protect the injectors and the high-pressure line from dirt.
6. Unscrew the injector and remove it from its socket in the cylinder head.
7. Remove the gasket from the fuel injector, noting its location.
Installation
1. Install a new gasket into the cylinder head. Screw in the fuel injector and tighten it to the specified torque.
2. Install the high pressure pipes and secure them with union nuts, tightening them to the required torque.
3. Connect the fuel return line to the fuel injector and secure it with a clamp.
4. Connect the ground wire to the battery and check the engine operation.