Injectors — removal, inspection and installation (VW Transporter T4)

Faulty injectors can cause severe engine detonation, very similar to the noise of failed main bearings. If such a malfunction occurs, let the engine idle and sequentially unscrew the union nuts of the fuel supply lines to the injectors. If the detonation disappears after unscrewing any nut, then this injector is faulty.

A faulty injector can also be identified by unscrewing the union nuts of the pipelines (consistently) when the engine is running at high idle speed. If the engine speed does not change after unscrewing any nut, then this injector is faulty. Injectors are checked using a special pressure gauge at a service station.

Checking the injectors

Engine	1X, DAV	ABL
New injectors	130 – 138 bar	155 – 163 bar
Wear limit	120 bar	140 bar

The first signs of faulty injectors:

• irregular ignition of the fuel mixture;
• detonation in one or more cylinders;
• engine power loss;
• excessively black exhaust plumes;
• high fuel consumption.

Removal

1. Clean fuel lines with cold cleaning agent.

2. Remove the fuel lines as a whole. To do this, unscrew the union nuts with an open-end wrench, such as HAZET 4560.

Attention! Do not change the shape of the pipeline bend. Remove the pipeline block completely.

3. Unscrew the injectors using a 27 mm socket wrench.

Installation

1. Always install new heat insulators between the cylinder head and the injectors. With the indentation facing upwards, the arrow points to the cylinder head.



2. Tighten the injectors to 70 Nm.

3. Tighten the pipe nuts to a torque of 25 Nm.