TDI EGR Valve disable

[muddyboots]

OK - I'm muchos confused now. Where exactly is this anti-shudder thing? Looking on my parts catalogue I have something called a "damper" on the front of the engine, with a round ball on top of it, and a vacuum pipe coming off it. I hope this drawed on pic makes sense?

Item number 15 is the vacuum reservoir.

The ASV and EGR are in the same housing.
EGR is operatied by the UFO on the top, ASV is operated by a small arm at the rear. Both have vacuum pipe connections (ASV = pipe 22, EGR = pipe 9).

Item 5 is the small metal pipe that connects the exhaust to the inlet, the EGR operates a small flap to open/close the end of it.

 

[basstard]

perfect explanation Lee,,, I'm **** at english when it comes to technical,,,

If you blank the #4 gasket or remove the EGR arm as Nic did in the pic I posted I guess the ecu will believe the egr is working and won't throw a CEL,,, what do you guys reckon?

 

[cheshire cat]

perfect explanation Lee,,, I'm **** at english when it comes to technical,,,] wish my Italian was half as good

[ Quote=If you blank the #4 gasket or remove the EGR arm as Nic did in the pic I posted I guess the ecu will believe the egr is working and won't throw a CEL,,, what do you guys reckon?

Egr valve and seat and diaphram and spring rather than "arm"
P.S. Carlo, did you get the pic with the "heater" in it or did it get lost?? again

 

[basstard]

Egr valve and seat and diaphram and spring rather than "arm"

that's why I said I'm **** at tech english,,, and then what would you do with knowing italian? plus bear in mind italian is a very complicated language compared to english,,,

Yes, I got the other pic, didn't understand much of it cos it was quite blurry [time for a new camera I guess ] but I made myself an idea,,, I'd like something similar on my beeza but I'm concerned about all the stuff you plan to do to wire it up to the electrical system,,,

 

[devonutopia]

So, it looks like if I remove the EGR unit as a whole then, it will be removing the anti shudder as well? How does the anti shudder work? If its also got a vacuum pipe connected as well? Hmmmm.

Oh well, time for me to get used to some shuddering then. LOL

 

[cheshire cat]

when the ingnition is switched off it sends vac from the res' to the diaphram, closes butterfly and then runs out of vac and resets to open for next start some high milage ones stay shut/no start next time

 

[muddyboots]

How does the anti shudder work? If its also got a vacuum pipe connected as well? Hmmmm.

Well, as you probably know, diesel engines generate much higher cylinder compression than petrols do.
Also, petrol engines have a throttle, so at idle (throttle almost shut), not much air is going in, so there's not much to compress, and when the engine is switched off, it comes to a fairly gentle halt.

In a diesel, there is no throttle - so even at idle, it's still having to compress the full volume of air, and because of the high compression ratio this is hard work.
So when you switch off and the engine slows to a halt, there will be powerful kick-back as the engine can't complete one of it's compressions and the partially compressed air in the cylinder forces the engine to turn backwards. This would make the engine rock quite violently. (Incidentally, I believe this is why the TDIs usually have one-way clutches in the alternator pulley).

So to avoid this problem, they stuck in the anti-shudder valve, which is basically a throttle that shuts off the intake when you switch off, to reduce the amount of air being compressed and therefore prevent kickback.
It operates off vacuum, actuated by a valve (The N239, or Item 10 in the diagram) and manages to stay shut for a few seconds after the engine has stopped turning because of the residual vacuum in the vacuum reservoir.

Here endeth the ASV lesson

 

[devonutopia]

But there's no way I can keep the ASV and remove the EGR - thats what it sounds like to me.

 

[basstard]

devon, are you reading posts or not?

block the egr pipe [replacing gasket #4 is ok as I see it] or do as Nic did, juast saw off the egr bits into the egr assembly,,, both ways keeps the asv in place and working but no egr,,,

and again, it's ONE HELL of a shudder on shut down, I assure ya,,,

 

[mwragg]

1. With the engine warmed up and running at idle in neutral and all accessories turned off (air conditioning radio etc)

2. Connect the scan tool cable and start upthe software.

3. select Engine Control module

4. Login in as 12233 (as access code)

5. Select "Adaptation" and go to block 3

6. Give accelerator a quick blip to open Egr Valve. should show 250mg/stroke (give -/+ 20mg)

7. The default number is 32768 change value to 33768

8. Select "test"

9. should change to about 350-370mg/stroke!

10. unplug, have a drive!

It is really simple, 2mins to do

Hi there

Recently got an Ibiza Cupra TDI 160!!

Just reading on www.seatcupra.net about disabling the EGR. I take note of your points, however, I fail to see how VAG-COM can turn the EGR off or down when it is in actual fact controlled by inlet vacuum at part-throttle. Anyway, would like to try your method...do you know where I can get VAG-COM, for free? I know it is available at www.ross-tech.com but this is only shareware and, without paying for the full-unlocked program, will not allow you to SAVE new adaption values.


Marcus

 

[muddyboots]

As far as I know, the EGR is controlled by the ECU, not by inlet vacuum at part throttle.

Mainly because - there is no throttle on a diesel and therefore no vacuum

 

[mwragg]

EGR query

Thanks, but there is a hose which runs from the air filter box to a vacuum unit from which a black plastic rod connects to the EGR valve spindle...

Anyway, that aside, do know know where I can get VAG-COM?

 

[muddyboots]

Because there is no inlet vacuum, because there is no throttle, there is a vacuum pump combined with the fuel pump.

This pump provides a vacuum supply to the black box on the suspension turret, and the ECU controls the distribution of said vacuum to the various devices hanging off the black box, of which the EGR is one. Which is how the ECU controls the EGR operation.

You might try asking about vag-com in the vag-com forum on here, as a thread about TDI EGR valves may have a limited audience

 

[mwragg]

EGR query

Thank you!!

That is really helpful. It is slowly staring to make sense now. I am confused, however, that previously when I disconnected and plugged the EGR hose to the vacuum unit the ASV seemed to stop working (the engine ran on a little as I turned off the ignition). At the risk of sounding totally stupid, I do not see how the EGR vacuum could affect the ASV vacuum...unless, of course, I have got the EGR and ASV mixed up and inadvertently disconnected the ASV. Do you have a photo you could post?

 

[sssstew]

the ASV is a small black plastic unit behind the back of the EGR. if you want to pop the pipe off you need to disconnect the one leading the large silver cap at the back left of the engine, sounds like you are disconecting too early in the system or the wrong item.

 

[muddyboots]

The ASV and EGR are in the same section of pipe and can be easily confused.
But the EGR unit is the circular metal disc thing on top of the inlet pipe, and the vacuum hose connection is quite obvious.
The ASV is fitted on the side, slightly more obscured from view.

Sounds like you got the wrong pipe.

You can tell which is the ASV, because when the engine is switched off you'll see the operating arm move, then move back to rest a few seconds after the engine has stopped.