I recently picked up a set of injectors for my Focus 1.6 TDCI, very cheap. They came off a car that had done 116k and suspect the cam belt had snapped. I believe they are Siemens. 

Occasionally, I get the 'learning limit reached' code on my focus which is at 160k. In the past I have added injector cleaner but for the last couple of years I've just filled up with the premium diesel every 6 months and have not had the fault code since. So I was over the moon to pick up the spares. 

Now, like everyone else, I have watched several YouTube videos on injector servicing and apart from the special tools involved, I'm not seeing anything particularly difficult. Especially, with the bottom end and nozzle cleaning. Actually, in all the videos I've watched so far, they just seem to strip the injector down, clean it and reassemble it. 

So, my question is, what is involved in injector servicing and has anybody on this forum successfully serviced the Siemens injectors themselves? 

 

 

Ok, so I called a couple local injector specialist to ask advice about getting my spares serviced. 

Interestingly, they told me that Siemens do not sell spares for their injectors and if you buy Siemens Injectors that claim to be reconditioned, then they are either using spares from another injector, or they have just stripped, cleaned, reassembled and tested them. 

As to servicing them yourself, the dark art seems to be having the extortionately priced equipment to test them. In one of the videos I watched, the test equipment uses 150volts when connected to the injector (this scuppers my idea of using a 12volt battery!!!). They test, the capacitor and resistance and use a micrometer to measure how far the head moves as well as a whole heap of other test. I believe that they then use this data to shim various parts within the injector. 

My car is at 160k now, so I guess when you consider how many squirts of diesel the individual injectors have done over this mileage, it's not a bad part compared to other seemingly simple parts that regularly break down. 

I think I'll send my spares to be tested and keep them stashed away for the inevitable 'learning level reached max'.