Unplugging EGR valve

[Chriseybaby]

So the garage I took the car to thought my rev bouncing was caused by the EGR (I'm not convinced)

I am right in thinking I can just unplug it and the car will run as normal but throw a light and keep the EGR closed?

Can someone confirm this for me before I disconnect it?

Thanks

[MarkTM]

Have you had it scanned?

You can't just unplug it to my knowledge, you can blank it off which will throw up an error which you will need to have mapped out for it to disappear.

[Chriseybaby]

Yes it was scanned with no faults. Sorry I read about disconnecting the maf to disable egr.

i might buy a blanking plate for a few quid to test out whether it is egr related

[zollaf]

you cant just disconnect the maf. i think you need to get it diagnosed properly.

[Chriseybaby]

It was an Audi specialist but Every garage I've spoken to doesn't seem to try too hard to diagnose and I don't want to just throw parts at it.

[MarkTM]

If the scanned with VCDS then they would have had the ability to run an output test on the EGR

16785/P0401/001025 - Ross-Tech Wiki (http://wiki.ross-tech.com/wiki/index.php/16785/P0401/001025)

As the above links show there are specific fault codes for EGR faults.

It is possible to run an engine without the MAF (I think Gups did) but probably not for any serious length of time, since a 5 minute job I'd probably advocate giving that a try, if it runs better disconnected then it narrows things down.

[stevo16]

Whats the MAF got to do with the EGR anyway cant just unplug like others have said blank and map out unplug and will possibly go into limp mode.

[Chriseybaby]

If I blank the egr will it go into limp mode or just throw a light on the dash?

i have been looking at mapping options but it's hard to know who to trust

[Gazwould]

C6 2004+ will throw an eml if egr interfeared with , holed blank , remap or egr adaption won't if done correctly .

But for best results , egr disable , blank and remap .

[Golf TD]

I had my car remapped and I got the egr delete I've had no problems

Sent from my SM-G930F using Tapatalk

[gupsterg]

@ChriseyBaby

I have been running by A6 3.0 TDi with MAF disconnected for probably over 3yrs now. For MOT time I have a neat little manual intervention/VCDS trick which clears the EML and allows car to pass (EGR valve still don't open with this trick, so no collected soot hits engine).

As you are aware I had idle rev bounce, as you probably know I threw a lot of parts at car:-

1. Throttle body (was on the way out at the time)
2. New MAF
3. New Battery (was orig factory when removed ~6-7yrs old)
4. New starter motor (as it died later)
5. Full set of injectors (as MVB were showing leaking plus white smoke at idle)
6. Latest VAG ECU SW done
7. Throttle body adapter clean

I have:-

1. spare EGR cooler/top intake manifold cleaned (2nd hand via ebay.de = very cheap)
2. lower manifold butterflies (a gift courtesy of SRT88)
3. lower manifold motor arms

Ready for swapping when clean lower intake manifolds, just haven't been _ _ _ _'d to do it :) .

When the MAF is disconnected ECU disables EGR system, so EGR valve stay closed. The ECU then reverts to a predefined set of calcs for injection IIRC, thus you may have a slight hit on MPG, I never noticed it (check my fuelly account). The car responds so well that if it's sipping a bit more juice I'm not fussed :D. Everything behind the EGR valve is collecting the sooting muck as it's closed, hence spare parts I have.

As you also know prior to the idle issue I had chain rattle and choose the route of bank account annihilation = full engine out with full set of chains.

My advise disconnect MAF and enjoy ;) , as long as you have VCDS I will explain trick via PM and you can always get car MOT passed. Only issue is when you gonna sell you'd have to have got enough work done so EML is not there. I have vowed I won't sell Zesty the A6 as she will probably break the new owner :D , so she's either gonna die under my ownership or I'm gonna go with her! LOL

[Chriseybaby]

Good to hear zesty is still going strong. Did you every think about mapping out the egr or don't you think that's what's causing the issue?

I don't have vcds so i may go down the remap route with egr delete.

Tempted to unplug the maf now and see what happens, she's just had an mot so no worries on that front for a while. I guess the mil can't be cleared by just plugging the maf back in then?

[gupsterg]

Yep she's well :) .

Did think about getting it mapped out, contacted a forum sponsor (haven't checked to see if they are still one). When speaking over the phone, discussing process, the guy asked me if I knew where the EGR valve was :bigeyes:, at that point I decided it wasn't the place for me.

Then I contacted MRC Tuning, was all set to go but IIRC my relocation hindered me finding time to go. After the move I just got way laid with things to do at the new place. I decided to just keep the £££ for any other maintenance. IIRC just like if a car has a DPF from factory and removing it is fail I would thing mapping out EGR would also be, but dunno really.

I forgot to add to the list above that I also replaced the glowplugs, I also have a new genuine EGR cooling flap unit sitting around, bought it off ebay for <£50 IIRC. I also checked MOTs and done ~30k miles with MAF unlplugged.

I believe the idle bounce is down to something related to charge air & egr systems, I spent so much of my own time and £££ on trying to sort it that nearer the end I was not prepared to invest more of both. Post 236 (http://www.vwaudiforum.co.uk/forum/showthread.php/138282-BMK-3-0-TDi-hunting-erratic-idle-revs-%28-Have-I-got-the-most-lemon-A6!!!-%29?p=782290#post782290) of the BMK 3.0 TDi hunting erratic idle revs ( Have I got the most lemon A6!!! ) thread has info to where I got with things and left it. With the MAF unplugged I get no idle bounce = not doing my head in. She drives so well (maybe better IMO) that I think can I be bothered?

[Sambor11]

So! You just unplage MAF sensor and you don't have any warning lights on dushbord? Or you done something else?

[gupsterg]

Unplug MAF = warning light on dash.

No way to remove warning light permanently other than have ECU modified with EGR delete.

I can remove warning light so vehicle pass UK MOT but:-

a) requires VCDS.
b) requires some manual mods to keep EGR valve closed so accumulated soot is not fired into engine intake system.
c) you have a time/number of starts as when the warning light will reappear with my method of fooling system, so it's not a permanent solution of removing warning light.

By unplugging MAF my car does not have idle rev bounce which gets on my nerves.

With my mod I can have vehicle pass UK MOT but is not permanent solution or best all round solution as EGR delete from ECU.

[snapdragon]

Hi Gup - I never had rev bounce but have EGR insufficient flow errors and so used your videos and posts and links to other threads to clean it - thanks for that!
When I eventually got it off it wasn't that dirty and lower intakes were replaced in 2010 just before I had bought it and were cleaner than many but still cleaned them up.
The intake ports in the head were worst - 2 were about 50% blocked.
I also found the EGR cooler flap broken off inside and also the pivot for it allowed smoke/fumes to escape into the engine compartment due to slop.
New one fitted and everything else cleansed up - I still get the same errors. I also broke the plastic vacuum pipes as they had gone hard and brittle like macaroni and are about £90 a set of 3.
I'll be troublseshooting the vacuum systems next, but spent enough this month.
In the interim, I disabled my EGR with a ball bearing in the vacuum pipe in the rubber pipe off the T peice on the vacuum pump.
The return spring keeps it shut and there is no vacuum to open it - it now just powers the brakes, not the EGR or cooler bypass flap.
The EML comes on about half way through the second 8 mile journey with no EGR function.
I also found without EGR, the engine is a bit noisier when coming back on the throttle after overrun.
Good luck everyone.

[boidy]

2 months ago i had a re map and egr delete. in nearly 5 years of ownership this is the best it's run by far.
should have had it done from day 1

[Gazwould]

It's a shame this emission control device to reduce NOx has to feed exhaust poo poo back into the engine to reduce combustion temps to produce less NOx .

Less early boost from bleed off exhaust gasses that should be spooling the turbo .

Less performance and mpg as the non combustible exhaust gasses replace oxygen .

All I've got to say is oxygen burn baby burn .