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Hello everyone, it has been a considerable time since my last post.
My 2007 W639 Vito 111 CDI has begun to have fuel-related troubles. Exiting the conversation!
The background is as follows: after performing repairs on an injector blow-by and the hold-down bolt threads, the car began to leak gasoline from its leak-off system. I suspected that I had been too forceful with the press-down clips on the plastic pipe fittings attached to the spigot pipes emerging from the side of the injector.I conducted a leak-off test and discovered that three of the injectors were defective, exhibiting excessive fuel leakage. Consequently, I acquired a whole set of replacement injectors, Honda copper washers, and new stretch hold-down bolts, and I replaced them together with an entirely new leak-off pipe system.

after a run test drive i noticed it was leaking yet again but this time knowing full well the leak off was just a dribble and the leaking wouldnt start until at lease five mins of running ,i then purchased another pipe set believing it must of been a dud set i had previously got and fitted another new set ,another test run and another leak ensued so this time i thought it must be having trouble to leak back into the in-tank pumped supply line where it is plumbed into via an alloy y adapter ,having looked at it i considered it could either be a clogged filter (where the in tank pump brings the low pressure supply into) or maybe a locked up non return check valve which is in the new replaced leak off pipe so i checked the valve using air line and a peice of stiff wire all good replaced filter and test drive ,still leaking fuel out of the weakest point of the rubber leak off sections between the injectors , this tells me the pressure of the system where it is supposed to bleed into is far too high ?

There must be someone available who can assist.
Kindly or
Is this forum as inactive as it appears?

Appearance?

The forum is quite active. Do you believe that such a statement is more likely to elicit assistance?

I sincerely apologise if my post caused offence. Based on my experiences over the years, it appears that very few individuals are willing to contribute or assist others. When such assistance does occur, it is undoubtedly invaluable, yet it remains challenging to connect with someone who possesses the requisite knowledge.

This site is free to use, and your post was made less than 24 hours ago. Individuals provide responses here at their convenience and leisure.

Increased participation on the forum would reveal that many users are consistently engaging with others and offering precise and prompt assistance on various topics.


Your observation on the statement "few if any want to contribute or help" is intriguing, given a brief review of your postings reveals that they mostly solicit assistance without any indication of your own contributions.

I thought his post rather caustic.

The fluid in the return line consists only of that which is not used during injection, namely the leak-off.

The common rail maintains constant pressure, with the injector using it as needed; ideally, there would be no return flow. However, we should anticipate some.
Consider doing an additional leak-off test to see whether any injector exhibits significant leakage. In compared to the others, it should serve as a respectable demonstration, given its novelty.


Inserting the plastic leaks into the injector may be challenging; I had difficulties with the new 'O' rings being very thick. Have you perhaps solved one?

What is the pressure on the rail? Have you verified the reading?

Is the leak occurring at the T fitting or at the top of the injector?