Lumpy Idle after motorway drive

[El Grobboss]

Transit Mk7 2.2 FWD T280 Euro 4 2007

Hello all,

Van is running really well other than diesel knock when cold and very slight hunting after a good long drive on motorway. I had EGR mapped out but didn't put blanking plate in , wondering whether with the excessive force gases could be escaping through if valve is loose, even though its been permanently closed before mapping?

Also seeing air in fuel lines, not sure if related as van starts on the button. SCv and PRV done and learns pass every time.

Any ideas greatly appreciated

[El Grobboss]

Forgot to mention, replaced fuel filter and injector leak off test was done at time of map and all kosher

Cheers

[DanMK7uk]

Normally recommend blanking and mapping.. are you showing any codes atall such as MAF codes ?

Air in the high pressure side will cause problems.

Were the SCV and PRV genuine ford or denso? Many a knock off denso are unfortunately floating around…

What brand of fuel filter is fitted?

You mentioned air, normally this will cause starting problems when cold… when left overnight fuel syphons back to the tank. You say yours starts well so unlikely…

One thing to check, the clear hose from filter housing to fuel pump can pin hole if rubbing so check that as it can only happen if it moves and allows the hole to be open ie resting on another hose.


Id probably put live data on and check fuel rail pressure when its acting rough, it should be 230 bar or very close to this at idle. If its hopping about, that will need rectifying.

[El Grobboss]

Hi mate, cheers for reply,

No engine management lights/limp mode or anything like that , just sometimes van is a bit "surgey" like Peter rabbit up the road and knocks when cold. No smoke whatsoever, so egr blanking and remap deffo doing its job and pulls great, just got these very slight fuel pressure fluctuations on idling when I pull up at a services after good run on motorway.

Will have a look on live data on forscan although going to be difficult to replicate near my house as it seems to be after a good run at 70 odd mile an hour. I've ordered a blanking plate so will fit that when it arrives.

SCV and PRV are both from Ford, im sure PRV is sound else it wouldn't drive so sweet but I guess SCV could be premature failure starting to misbehave? Part will be still under warranty do you think i should try and exchange with Parts plus saying its faulty?

[DanMK7uk]

It’s unlikely but possible.. that is where looking at the rail pressure would help diagnose mate.

Get the blank in, if you have forscan maybe do a run of fuel learns again. Easy to do.