Originally Posted by Diesel911

My opinion and some experience; one has to believe or accept the below:

I worked in a Bosch Certified Fuel Injection Shop for 5 years and at that time the Guy I worked for had over 20 years experience not just with Bosch but multiple makes of Fuel Injection equipment.

Also Bosch had a Catalog with the Pop/Opening Pressures referenced by application and the Nozzle Number that listed the Pop Pressure they wanted their Injectors set at.

Neither my Bosch trained Boss or the Bosch Catalog say anything about having the Injector Opening Pressure set slightly Higher.

What I believe he is actually doing is merely setting the opening pressure above the 135 bar pressure stamped on the Injector Body. Mercedes allows a Pop/Opening Pressure range of 135-143 bar that he can work in when installing new Nozzles.

Part of his job is sales and it sounds to me like he is trying to think he did something extra for you and that he has some special knowledge about your Injectors that other Bosch Certified shops do not have.

When you are a new as I was when I stated working in Fuel Injection; Rebuilding Injectors is the first job they start you off at in a Fuel Injection Shop because it is the easiest to do.