Bad injectors can also be detected by loosening the high pressure fuel line union nuts one by one while the engine is running at high idle. If the engine speed remains constant after loosening the union nut, the corresponding injector is faulty. It can be checked with a pressure gauge in the workshop. Injection pressure value 134±4bar.
The first signs of damage to the injectors are the following:
- misfiring (outbreaks) in cylinders;
- knocking in one or more cylinders;
- engine overheating;
- reduction in engine power;
- strong black smoke from the exhaust pipe;
- high fuel consumption.
Removing
Disconnect the negative cable from the battery.
Attention: This will erase the data from the electronic memory blocks. See instructions «electrical equipment».
Thoroughly clean the high-pressure fuel lines and fuel return lines with special cleaner or clean diesel fuel. If the high-pressure fuel line brackets are removed, mark their installation position.
Completely remove the high pressure fuel lines by unscrewing the cap nuts with a special cap wrench.
Attention: Do not change the shape of the fuel lines. Put on suitable protective caps on the injectors and on the high pressure pump so that dirt does not get inside.
Carefully pull off fuel return lines (3) from nozzles. These fuel lines connect the injectors to each other. At the last nozzle, i.e. closest to the gearbox, there is a blind cap.
Unscrew the injectors with a 27 mm deep socket. Protect the nozzles at the bottom against dirt with protective caps.
Attention: It is necessary to ensure that the nozzles do not fall out.
Take out the heat shield (1).
Installation
Be sure to use heat shields between the cylinder head and the injectors. The recess must point upwards, with the arrow pointing towards the cylinder head.
Tighten injectors to 75 Nm.
Tighten union nuts for high-pressure pipes to 20 Nm.
If they were removed, insert the fastening brackets in accordance with the marking made earlier.
Install fuel return lines.
Connect the negative cable to the battery. Set the clock and enter the required codes.
Start the engine and check the fuel system for tightness.