How to replace a Diesel Injector Nozzle

                PLEASE READ THIS INSTRUCTION NOTE FULLY

These Instructions are for your guidance only and any repair work carried out is at the risk of the repairer. 

Prior to removing the Injectors, thoroughly clean the area you are working on.

As each injector pipe is removed from the Injector, fit the plastic cap supplied over the Injector inlet to eliminate contamination. Leave these caps on until Injectors have been cleaned.

Once removed from the engine the injectors can be cleaned with a wire brush and washed in a light oil solution.

Carefully remove the injector nozzle cap nut, remove and inspect the old nozzle. If fuel contamination is suspected as cause of failure (needle seizure) then this must be addressed before installing serviced Injector.

The carbon deposit in and around the nozzle retaining cap nut can be removed with a wire brush, washed and blown off with an air line.

Wash the nozzle sealing face on the Injector body, blow across the face with an air line and inspect for damage. Also inspect for any damage to the nozzle locating dowels where fitted.

Remove the plastic cap from the Injector inlet connection and blow through the Injector with an air line, and immediately refit the protective cap.

Unpack the new nozzle being careful to keep the needle inside the nozzle (match fit).

Wash the nozzle and needle in a light oil solution and ensure the needle moves freely within the nozzle.

Fit the new nozzle ensuring to align the relevant holes with the locating dowels (where fitted).

There will be a gap between the nozzle face and body, this is normal as there is spring tension against the nozzle needle, refit the nozzle cap nut. Torque values depends on application and can be obtained from this site, however a typicle torque value for a screw in type injector is around 90Nm.
The Injector can now be ‘pop’ tested at your local DFI workshop and the pressures set to manufacturer’s specification. They normally make a nominal charge of a few pounds for this service.

Alternatively you may decide to refit the Injector (pressure will not deviate far from the original setting). The choice is entirely yours.
Refit Injector but prior to removing protective cap, clean around the high pressure Injector pipe nut and olive, Crank engine until fuel is injected from all of the pipes thus ensuring we have complete cleanliness when reconnecting the high pressure pipe to the Injector.

 * Relates to Injectors where a pressure adjusting screw is used, rather than the more commonly used pressure adjusting shim.

Finally fit seat washer and protective cap over nozzle until the Injector is ready for use. Only remove the protective cap from the inlet connection after installation into the engine and following cleaning of the pipe connections.