I've got a massive headache in that I'm struggling to understand why my car won't run as it should!! HELP PLEASE???

The history

Cars an 06 vrs and has been stood for a few months now and was running fine when I left it.

I've now come to try & get it running / MOTd and found a world of problems.

The problem

Car starts & idles fine but when I try to rev it it just stutters & the engine shakes violently & pours out clouds of black smoke. If I try to pull away it just dies!!

Diagnosis so far

If I disconnect the vac pipe on the EGR valve it revs cleanly & appears to drive ok (up &down the drive at least)

I've had the EGR valve off, given it a damn good clean and no real change!!

I've tried disconnecting battery overnight to reset things, again no change.

What I don't understand

The EGR appears to be operating due to the fact connecting & disconnecting it changes how the car revs so it's not faulty right??

With it connected it seems like the car is running solely on exhaust gas as you rev it thus poor combustion.

Simply pulling the vac pipe off & plugging it will throw a mil light at some point soon won't it??

Could the vac unit be doing something strange?

Could the problem be something else non EGR related?

I dont have the small gasket yet but don't see how this would solve the problem completely!

Has anyone any bright ideas as to what the problem is? I've been through many threads but can't find any inspiration!!

Unfortunately I don't have the ability to read any of the codes & the cars stuck on the drive so running out of options :( help help help please?

Best thing to do would be to try a different EGR valve. I was having erg issues low boost, weirdly a lack of black smoke and crap mpg. After some advice from Andy at Blacksmoke I got a non leaking EGR cheap off a golf tdi gt. I cleaned it with oven cleaner until it shined, put it on and my word it pullls very hard now. I cant belive the problems egr's can cause. My car also did not like the EGR delete for some resaon so im stuck with cleaning it out now and then but hey i did not like the idea of pumping out nox everywhere anyhow. Also make sure none of the vac lines are persihed or pinched where they are clipped. Could also be a faulty n75 vac box.

Edited 6 September, 201213 yr by RAPTURE

Best not to guess what the problem is and get the ecu read for error codes. If the EGR valve is the problem the codes will tell you.

Disconnecting the battery will have deleted all the learnt values on the ecu. Driving the car is the only way for the ecu to relearn.

Has the diesel gone stale or gummed everything up?

SN

Edited 6 September, 201213 yr by Steve Neate

It sounds like the EGR is being opened by the Vac box as you say! One of methods I use to disable the EGR function gives exactly the same results if the Vac pipe is not disconnected, and that fully opens the valve.