hello
biz here --recently a had similar symptoms -my buddy mechanic replaced the MAF and all good ---i was key drooling at EGR valve thinking that it needs a clean or worse but i was wrong .

 

The MAF monitors the correct working of the EGR system so occasionally a MAF fault can show up as an EGR fault.

 

Cheers guys, I already changed the MAF, MAP & N75 & I'm happy that they are operating properly.

Van still limps when given the beans though and I found that the EGR cooler valve cannot be operated by vacuum. Yesterday I found that I can push the valve over with a screwdriver and it will happily stay in any position I place it. I would have assumed that it was pulled into one position by vacuum with the other position achieved by a spring once the vacuum is no longer present. What I'd like to know is - with the EGR cooler valve rod all the way over to the right, is the flap open or closed? From looking at various pictures I now get the impression that with the rod over to the right the flap is closed meaning that I am probably not loosing boost pressure through it ( drat ).

I do have a blanking plate which I might throw in to discount this valve altogether but I'm a curious chap and would rather understand the problem fully.

I'm going to give her a run today with the EGR cooler flap in the other position ( rod fully left ) to see what kind of performance I get.
I was curious to know if anyone could explain to me how the EGR cooler flap should operate so that I can get on and find an economic way to fix it ( new EGR cooler from vw is over £400 ) or discount this red herring & move on with my lack of performance investigation.

To summarise:
What is the default position of the EGR cooler flap? ( open / closed ).
What position is the vacuum operated arm in to achieve those positions e.g. fully right = closed, fully left = open.
Could it be possible that a faulty EGR cooler flap might cause underboost?

Cheers Guys

 

This can't be helping I:

 

Hi I have an egr and cooler I removed from my engine when I mapped it. Let me know if you need it. Removed at 108k

 

Hey thanks Chris, much appreciated mate.


Van is in the workshop at the minute, when it returns I'll also have a spare EGR valve and cooler
And hopefully a van that works!

 

I modified a vacuum device from a 1.9 tdi Passat to fit my BNZ. Fairly easy job, all sorted in about 45 mins. Still going strong after 2500 miles T:

 

Cool, I love repairs like those T:

 

This EGR Cooler Valve flap thingy.

Mine BNZ 2.5 2006 the ball joint to the cooler is not movable by hand. It must need some serious vacuum to open / shut it.
Is suppose to be difficult to move or like the turbo attuator where you can move it 5-10 mm?

Nik

 

Mine moves very easily with 1 finger, it sounds like your egr manifold flap is sooted up by the sounds of it.

 

Yep I agree, should move easily.

I noticed that mine was very stiff but I was able to loosen it up with some wd40 and by opening and closing it several times.
I'm not sure if mine got stiff and helped to split the diaphragm or if the diaphragm split leaving the flap sat in one place for so long that it simply sooted up.

Here's an easy test you can try: When you start the engine the rod should pull across to the left, if it doesn't I would stick a vacuum hand pump on it and see if it can hold a vacuum. When the engine is shut off the arm will return to the right, you can hear it move from the cab on my van.

The pumps are really cheap on the internet, I used mine to check various parts of the vacuum system including the VNT.

Cheers,
Daz

 

Mine was deffo stuck (shut or open?)

Anyway I had to take the pipe from the cooler to the inlet off to examine the flap. Slightly sooted but not restricting.
I got a flat screwdriver and I could just get it between the elbow and the external flap stop. It started to slightly move, added WD40 to the inside and wiggled the elbow until it moved more and more and would shut on its own. Took about 30 mins of wiggling open and shut to allow it to fully open and shut when released.

So from this I guess either the pipe is not supplying pressure (need to see if it will move on rev). Leak if so.

So if this has been shut all the time and wouldn't open, what would the issue?

Is this flap utilised as a wastegate?

 

I've just tested to see if the actuator is moving the arm to the egr cooler flap on reving and it doesn't seem to be moving it.
If it's not moved for a while suggests why it was seized shut.

Is it suppose to move on acceleration?

Pipes from the actuator go to a sensor, not sure what that is and that seems to go or finish up at the N75.

Faulty N75
Faulty other sensor?
Pipe leak?

I do have a spare N75, so it could be that.

 

After research 1K0906283A EGR Vacuum Solenoid Valve is the other component

 

On idle the egr flap should be open (rod pulled to the left looking down from above) to allow exhaust gas into the inlet system, this decreases NOx levels.
With the engine on boost the valve closes (rod settles to the right looking down). If the egr flap has stuck open you could have been losing boost pressure back into the exhaust system.
If you just rev the engine at standstill I wouldn't think the valve would close.

 

That's right, revving at a standstill doesn't change the position of the flap.

All you need to do is start the engine, the rod should move across to the left, when you turn the engine off the rod moves back over to the right.

To test mine I pulled the vacuum line out, attached a hand operated mechanics vacuum pump, tried to pull a vacuum and couldn't ( the rod stayed over to the right ). So in my case I needed to replace the vacuum pull rod. You can't seem to buy these separately from the rest of the egr cooler but fortunately the vac rod from a pattern cooler I brought for £110 fitted straight on so I didn't have to go to the trouble of changing the cooler ( at the time ). I've since changed the cooler as well but that's a different story!

 

Cool thanks for the info.
Mine is engine OFF, fully extended and pushed to the right. Engine ON and it's in the same place to the right.
So I guess it's shut all the time and as the actuator has a spring to push it to the right and is bust as in this post then it needs renewing.
So a full unit is required. Great

 

Isn't the flap used for direction rather than open / shut. Does it either allow the gas to go direct or via the cooler.

It's the valve in the EGR that allows it back into the inlet.

So if this flap isn't working and the gas is going directly without cooling. The engine could overhead?

 

I'm not sure how the flap works, it's not air tight that's for sure because I was able to blow through the cooler with the flap in either position.


Mine was stuck like yours too and it never overheated.

 

Yep, the more I research the flap in this cooler the more I don't find a purpose for it.
The cooler itself doesn't look big enough to cool it down fast enough.
If open or shut it doesn't change the engine note.

I could probably understand if this assists any over boost when the turbo is assisting regen but I'm not sure you would get EGR when in regen?

Is it restricting?
Does it allow quicker warm up when shut?

 

I'm not sure how it works but I did find this generic description:

'The cooler bypass (operated by a vacuum diaphragm) is only in the closed position when the engine is cold'
Once mine is back I'll run it up to temp and see if the flap moves over.

 

Yep, I've looked at other cooler diagrams and some suggest the flap is for additional cooling.
So by default you get 50%, I guess allows the engine to warm up quicker?
If hotter then opens the flap to allow 100% cooling.

That said I always thought the EGR valve before the intake only opened while the engine was cold?