As you guys would be aware, I am carrying out a valve grind and de-coke on my Astral Silver 6.9. Prior to dismantling, the car was not exactly a sparkling performer in the acceleration stakes, but a lovely and effortless cruiser on the freeways.
As part of the work, and prior to re-installlation in the inlet manifold, I was able to get the injectors tested. To say that the result of the testing was a disappointment, is putting it mildly. Out of the eight, from memory only one was holding pressure properly and providing a satisfactory spray pattern. The other seven, in one form or another, are in some way faulty - to the degree that one would waste their time refitting them to the engine. Really, it is a surprise that the car ran at all.
Therefore, what is one to do ? Clean them and, if so, how ? Somewhere I have seen one of S-Class' pictures of ultrasonic cleaned injectors. They looked like new, but did they work after cleaning and what were they like prior to cleaning. As it stands, the internals of the injectors have a tiny coneshaped filter, and a spring loaded metal valve retained by a collet similar to a normal valve. My contact that tested the injectors maintains that they cannot really be cleaned as there is no way of cleaning the filter and no way of blowing back any dirt particles on account of the spring loaded valve. Anyone have any thoughts on this ?
What I found also was as follows - and it relates to storage of spare injectors. In my opinion, they need to be stored in some sort of lubricant to stop the internals from drying out. I had quite a lot of 'dry-stored' injectors, mainly the brass type, but only three out of about twelve passed the pressure and spray test. Some of them didn't work at all. Tapping them sometimes made a difference, but not good enough to refit them with peace of mind. I also had about twelve steel type injectors that had been sitting in a petrol/oil filled container, and all bar one tested well enough to be re-used. Thus, I am really looking forward to how the silver car performs once the job is completed. There should be a considerable improvement. Regards Styria
As part of the work, and prior to re-installlation in the inlet manifold, I was able to get the injectors tested. To say that the result of the testing was a disappointment, is putting it mildly. Out of the eight, from memory only one was holding pressure properly and providing a satisfactory spray pattern. The other seven, in one form or another, are in some way faulty - to the degree that one would waste their time refitting them to the engine. Really, it is a surprise that the car ran at all.
Therefore, what is one to do ? Clean them and, if so, how ? Somewhere I have seen one of S-Class' pictures of ultrasonic cleaned injectors. They looked like new, but did they work after cleaning and what were they like prior to cleaning. As it stands, the internals of the injectors have a tiny coneshaped filter, and a spring loaded metal valve retained by a collet similar to a normal valve. My contact that tested the injectors maintains that they cannot really be cleaned as there is no way of cleaning the filter and no way of blowing back any dirt particles on account of the spring loaded valve. Anyone have any thoughts on this ?
What I found also was as follows - and it relates to storage of spare injectors. In my opinion, they need to be stored in some sort of lubricant to stop the internals from drying out. I had quite a lot of 'dry-stored' injectors, mainly the brass type, but only three out of about twelve passed the pressure and spray test. Some of them didn't work at all. Tapping them sometimes made a difference, but not good enough to refit them with peace of mind. I also had about twelve steel type injectors that had been sitting in a petrol/oil filled container, and all bar one tested well enough to be re-used. Thus, I am really looking forward to how the silver car performs once the job is completed. There should be a considerable improvement. Regards Styria
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