2.2 TDCI leak off issue

[Kilo82]

Hi all it's been a while! I've recently come across a problem and I've not found a solution as of yet hence the post.

In short i have replaced injector number 4 washer seal and got everything apart/back together without issue but when I started the car it's developed a small leak at the final junction of the leak off pipe run before heading back to the fuel filter. This was not an issue before I started the work so now I'm scratching my head as to what I could've done??

Basically pressure has built up in the leak off pipes running from Injectors 1-3 as I have disconnected number 4 completely from the circuit and blanked off it's connection to the leak off circuit and it's still being forced past my blanking plug and there shouldn't be that much pressure in that circuit to the point it leaks.

Now what I have already tested; No 4 leak test- not excessive (approx 15-20ml)

Fuel filter output- Good flow so not blocked

Changed pipe over in case its old/cracked etc- Same with brand new pipe and connector.

All related pipework-nothing noted.

Haven't done- Leak off test on injectors 1-3- I don't want to leave it undriveable on my drive as the connectors will break (No 4 has a new one) I know all 4 need testing to be accurate.



I'm at a loss for now as to why it's doing this since the washer change but any help or advice or knowledge will be appreciated!!

Cheers
Steve

This is the last junction where it leaks when running-

[Grisleigh]

There is a youtube video by a chap called "Alan Howatt" that had a similar issue with a MK5 Mondeo 2.0 TDCI

If I remember correctly it was a faulty Module??

https://www.youtube.com/@alan4x