[Engine] Knocking sound like engine stops for a split second when driving

[robertlaurenson]

Hi all, 
I have had my 57 plate berlingo 1.6hdi for a year now, I did the timing belt a year ago at 110000 miles, had 2 oil and filter changes since. I noticed a problem early on in the fuel system. If the van gets below half a tank it starts spluttering do I just havent let it get down that far but more recently this new problem has started, I changed the fuel filter at the back of the engine a few months ago after having what I thought was fuel starvation issues but turned out to be the issue I mention of going below 1/4 tank. Anyway its like a similar issue now, driving just the other day and at 60mph, it feels like a jolt, no drop in revs but it feels like the engine stops for a split second. That's the issue now, I wonder if it is maybe a fuel issue still, possibly a problem with the pickup or sender unit etc, any help or ideas would be much appreciated. 
Thanks 
Robert

[Broken arrow]

maybe the tank breather is blocking, as the fuel goes down it creates a bit of a vacuum in the tank and the pump has trouble pulling it through for a second or two...does the fuel cap make a whoosh noise when you open it with the tank low on fuel?

[robertlaurenson]

maybe the tank breather is blocking, as the fuel goes down it creates a bit of a vacuum in the tank and the pump has trouble pulling it through for a second or two...does the fuel cap make a whoosh noise when you open it with the tank low on fuel?

No whoosh sound at all I'm afraid, is there a pump in the tank on these units? Or is it all done from the main HP pump?

[jj9]

EGR valves can often give that split second loss of power but that's normally low down in the rev range and when you are pulling away from rest, could be worth checking out though.

Temporarily fit a blanking plate to the EGR and see if the problem is still there. 


.

[robertlaurenson]

EGR valves can often give that split second loss of power but that's normally low down in the rev range and when you are pulling away from rest, could be worth checking out though.

Temporarily fit a blanking plate to the EGR and see if the problem is still there. 


To be more specific it seems to be lower down the rev range as you say, and a lot of time when strain comes on, overtaking, going up hill etc, drop her down a gear she does it, ill try a blanking plate on the EGR and see what happens though.