Hi

I have ford transit connect 1.6tdci 2014. 

I have an issue where engine is running rough when everything is connected as is should be. 

I did injector leak down test and while doing it engine was running perfect.  I have eliminated injectors, all 4 running at the same numbers. 

When the injector return fuel line is disconnected engine is perfect, when connected back in again engine is running rough/ knocking sound from around 1200 to 2000 revs. All this goes away when the return fuel line is disconnected. 

I got the second hand return fuel line but that hasn't solved the problem. 

Is there something else I should be looking at? Where could be the problem?

I really appreciate all the help.

I was going to suggest a kink or blockage in the return line.  But if two are the same then it can't be that.

Possibly a blockage on the connector where the end of the return line is?  Are there any valves after the return line that could be stuck closed? 

10 hours ago, TomsFocus said:

I was going to suggest a kink or blockage in the return line.  But if two are the same then it can't be that.

Possibly a blockage on the connector where the end of the return line is?  Are there any valves after the return line that could be stuck closed? 

Thank you for your suggestion.  I had a good look at the lines and there seems to be a valve, right passed the double connector. Maybe I am just very unlucky to have 2 sets of lines that are blocked? I have used sirange to force some diesel into the line and a lot of black diesel came out. I have left it overnight with the injector cleaner to see if that helps. 

I will attach the picture of the line from the interent. There seems to be a one way valve just pass the double connector. 

I will update on the progress.

Hi

How did you get on??