D4D, Doin Me Head In

[deedar]

evening all,

hope someone can help me out with this problem,

I own a D4D 2004, 91000mls on clock, the car drives ok when driving round town, but when I get on motorway an go over sixty mph within 10mls I lose power, I can put my foot flat to floor an it just about holds the speed, but if I take it out a gear an coast down hard shoulder for a couple a hundred yards, it picks up again an runs as normal.ive had my mate who is a fitter ov 20yrs, sat next to me with a laptop plugged in , an when it dies the reading on laptop comes up as normal, not a singal problem comes back, time after time, nothing lights up, ive put new fuel filter on, then had full service, still does it, its doin me head in, please can anyone help

cheers in advance neil

[Badgersdad]

Sounds like fuel starvation,check fuel cap vent is not blocked,try driving with fuel cap loosened to allow air in .

[avensisd4d786]

does it only do it when its up to temperature, or just over 60 regardless of temperature.

my first point of call for these d4d for powerloss with no codes is to inspect/clean egr valve and replace if necessary.

[deedar]

does it when sat at sixty, but saying that we came back from Horncastle an I was on an off the gas due to back roads an it still managed to do it twice, its so irregular you cant pin point it to a certain pattern, when we had laptop plugged in we went from Donny to goole to blyth, idid half a tank a derv that night, an it played up after 2mls at sixty,then it went ok for 10mls, then it went ok for 6mls, I found if I dipped clutch an revved it, it coughed abit then kicked in again , let clutch out an off ya went , but now it doesent always do that now, tonight I came down A1 from A639 at ponty to A635 Barnsley rd turn off cant be more than 8 mls did it twice pulled up at round about revved it sem,t ok pulled off, nowt ther then in a split second ya off like a rocket, I will try fuel cap tmoz, an wat is egr valve please, thanks for the replies neil

[gjnorthall]

There are a few possibilities but in the first instance I would follow the recommendation to clean the EGR valve and add a can of BG244 to the fuel tank. Theres a plethora of stuff on cleaning the EGR - use the facility to search this forum. Presumably you've checked for stored fault codes?

[deedar]

yes no codes stored, put a couple a different addatives in [redex] will try EGR thanks neil

[steve_lj]

I had similar issues as what you describe but did get fault codes/mil light on. New SCV valves sorted it out.

[IMweasel]

Had similar experiences a few years back. The main causes of this behaviour are indeed the EGR,SCV valves,VRV/VSV valve(s). Possibly there's a combination going on. SCV replacement and EGR cleaning cured my car for 2/3rd

The VRV/VSV cleaning did the rest. These are the easiest to begin with,just take the hoses off one by one and clean them out using WD40. You wouldn't even have to take them out.

But if you want to do more extensive testing, see how they behave (on your desk) when 12V 1A power is applied, they are basically 3-way valves that have either a path that allows air to flow between a and b OR b and c. If the mechanical part inside does not work properly, vacuum cannot get/stay in the vac chamber, which controls the actuator for the turbo valve. And when this is going on, you will indeed have lack of power, with zero chance of seeing faulty values with your laptop. And indeed revving the engine can overcome it. (probably because the vacuum is increased)

[sich1]

if it is sticking turbo vanes archoil6600 sorted mine out nicely