Audi a3 1.8T turbo issues bit of help please.

[PowellyEG]

Hi guys looking for a bit of help.

I bought a 1.8T A3 last night, on the test drive a few days ago it was fine but after picking the car up / on the way back i noticed it wasn't wanting to go over 3K revs, also got a bit juddery going into 3rd at 3k.. so thought this is strange..Limp mode maybe?

Upon further investigation I found that the the boost had been turned up (over flow valve?) was unscrewed all the way out (see pics) and from what I can gather was a fail safe as it was running something like 20psi? maybe?? so fail safe maybe?

What ive done is Screwed it back in most of the way but left room for overflow (does any one have a guide on how many turns is safe, for better boost on these valves?) but heres where my problems start:

Since doing this it drove fine for about 10 miles, I got on to an open spot of road and gave it some boost (as ive only had the car a few hours wanted to give it a run) then from nowhere it began making a sound like the exhaust was blowing / like I had no back box, its was very loud exhaust noise. So I pulled over and it was like the exhaust had blown... now its get wierd, I turned the car off, jumped out had a smoke whilst I had the bonnet up left it for about 5-10 mins jumped back in thinking daymmnnn Exhaust blown and the noise suddenly disappeared? Faulty cat maybe, but whats strange is there was no faults on the dash lights. Has any one had same issues?

Another issue Ive found is when spooling up in 2nd it gets to about 4k-4.5k and has the slightest of hesitations 0.1/0.2 of a second when running through the boost range, is this normal?

All help greatly appreciated guys, as im an Audi noob, just made the jump from JDM to Vag having owned many Honda Civic's.

Thanks

 

[PowellyEG]

Just looking for some advice peeps thanks

 

[s3dave]

I would get the bleed valve removed and put the n75 valve back in, and go from there...

 

[<tuffty/>]

What Dave said...

Judging from the MAF housing in the first picture you have an AGU engine code... these engines are more tollerant on bleed valves but... if not done right they will cause trouble...

Do you know if the car has been mapped? if not then its a little dangerous to be running 20psi as your fuelling may end up going lean and the ECU is too dumb to know whats going on...

Fit the N75 back on (assuming you have it) if not then just remove the bleed valve connecting the pipes directly together which will mean you will run on actuator pressure until you can get the car to a specialist (not a normal garage or a main dealer) to get the car checked over...

If you want to have a go yourself though (and why the hell not!! ) then you should invest in VCDS so you can log the ECU and check for fault codes... its the best investment you can make if you plan to do your own work...

<tuffty/>

 

[Metro]

Another issue Ive found is when spooling up in 2nd it gets to about 4k-4.5k and has the slightest of hesitations 0.1/0.2 of a second when running through the boost range, is this normal?

Well, I've got a similar issue to this, I've been told its just what happens with these engines... Audi had a look in to it when the ignition coils were changed, but it seems to have gotten a lot better since... Phone your local audi dealership and ask if your car was recalled for the ignition coils? Free and a free health check + valet

 

[<tuffty/>]

Well, I've got a similar issue to this, I've been told its just what happens with these engines... Audi had a look in to it when the ignition coils were changed, but it seems to have gotten a lot better since... Phone your local audi dealership and ask if your car was recalled for the ignition coils? Free and a free health check + valet

Its an AGU so won't have the push in coil packs that are part of the recall... If its remapped/got a bleed valve then the last place you want to take it is an Audi dealer...

Get the car scanned for fault codes as a start point... MAF does just about everything on an AGU so could be this adding to your issues but that daft bleed valve won't help and MBC/bleed valves are ****e on part throttle response too...

So...
Get the N75 put back on..
Get the car scanned for fault codes...

Start from there and post any faults etc that come up (if they do of course)

<tuffty/>

 

[Metro]

Its an AGU so won't have the push in coil packs that are part of the recall... If its remapped/got a bleed valve then the last place you want to take it is an Audi dealer...<tuffty/>

Sorry Boss, Ive only been on the audi scene for 2 weeks now, cheers for the info though! atleast im learning!

 

[<tuffty/>]

Sorry Boss, Ive only been on the audi scene for 2 weeks now, cheers for the info though! atleast im learning!

No worries fella... its something I wouldn't have known 3 years ago when I got my S3 either

<tuffty/>

 

[PowellyEG]

Thanks guys had similar advice from friends about taking the bleed valve off and run an oem pipe. Ill do a search on the N75 valve but can I run it without any valve i.e just run another oem pipe?

I am unsure whether the cars been mapped as ive only had it like 24 hours and tbh I bought it off a young girl who didnt do much with it, her fella fitted the BMC induction kit and the dump valve/ boost gauge? < will having the dumvalve / Boost gauge add to my issues here?

 

[s3dave]

You need to do some work:

Bin...or put to one side:
bmc, dump valve, bleed valve/MBC

Shopping trolly :

jetex air filter, audi BOV or an uprated one like forge 007, N75 valve...... then you should see normal behavior , when all is good you can start thinking about MBCs etc.

Do you know if it has been mapped?

 

[PowellyEG]

Car hasnt been mapped can i use a straight pipe instead of an N75 valve?

 

[<tuffty/>]

Car hasnt been mapped can i use a straight pipe instead of an N75 valve?

For now yes... this will allow the turbo to run on actuator pressure until you can get it sorted...

Sounds like someone has had a real hack about under the bonnet... not surprised you are having issues if its not been mapped...

As suggested by most above, better off returning the car to std spec components, eliminate the issues and start again..

<tuffty/>

 

[PowellyEG]

Exactly, what still confuses me is the exhust blowing type noise for exmple:

Driving normally its as quiet as a mouse, then giving it boost up to around 4k revs its fine but when giving it some through second & third in boost it is if the exhaust tone dropes to what I can only describe as having no back box, very loud like a straight through, then mysteriously when ive slowed down, and pulled up let it cool down it goes away?

Now ill try removing the bleed valve / pipe work tonight but im still concerned over the exhuast tone.

 

[aragorn]

maybe a cracked weld on a box or something that moves when your giving it some??

 

[PowellyEG]

Ok guys So heres what im looking

So i take it thats my n75 valve on the right and coming out of the pipe is the bleed valve to the left, am i right in thinking, remove the valve and reattach the pipe??

 

[<tuffty/>]

Ok guys So heres what im looking

So i take it thats my n75 valve on the right and coming out of the pipe is the bleed valve to the left, am i right in thinking, remove the valve and reattach the pipe??

Yep... result

<tuffty/>

 

[PowellyEG]

Were gunna swap that over then check for codes/ boost leak

 

[PowellyEG]

Ok so issue 1 has been resolved, I now have boost back, shame its raining as i would take it for a full on blast. Ive been advised as well to swap all the breather pipes as some have minuscule hairline cracks. Ill take it for a good blast see if i still get the exhaust noise / issue failing that could be a cat issue / down pipe issue??

 

[<tuffty/>]

Gaskets are the first port of call tbh... manifold to turbo and/or turbo to downpipe are favourite...

<tuffty/>

 

[PowellyEG]

Funny enough im down you neck of the woods wednesday, gotta meet a lad to sell some rims @ Michael Wood services lol

Thanks for your help, ill get these issues checked out we just ran out of time earlier got too dark.

 

[badger5]

get a smoke test done, as it will easily find your potential leaks in one go... might save you some time/££ on swapping stuff trial and error stylee

 

[Routledge]

Hey Powelly welcome to the boards. Recognise your username from CRX-UK

 

[PowellyEG]

Was gunna pm you on crxuk didnt know u had an audi

 

[PowellyEG]

Ok im still getting the exhaust problem.

Gaskets turbo/ downpipe, faulty Cat, smoke test, cracked weld all seem viable options but when giving it boost up to around 4k revs its fine but when giving it some through second & third in boost I hear a whoosh like boost leak sound, then it is if the exhaust tone dropes to what I can only describe as having no back box, very loud like a straight through, then mysteriously when ive slowed down, and pulled up let it cool down it goes away on its own?

Its very strange and intermittent, only happens when in high boost feels like somthing pops get like a whooosh noise like boost leak then the exhaust tone drops to as described no back box noisy.. no dash lights,

Ive found this thread similar symptoms - Fourtitude.com - Boost Drop/Exhaust Note Changem having a read now but any one had a similar problem??

 

[<tuffty/>]

Gonna be a tricky one to diagnose without seeing/hearing the issue tbh... if yo have checked all the hoses/pipes/exhaust/fault codes etc then all thats left is to take it somewhere with experience in this kinda thing...

I have seen lots of cars that have been checked over by the owner who have found nothing for it to be staring you in the face....

The only way to start diagnosing issues like these is to be systematic and eliminating potential issues as you go... its not unusual for stuff to be missed if you are not sure what you are looking for... all been there

<tuffty/>

 

[Gops]

My cousin had a problem similar to the exhaust sound.. Was fine when he was cruising but when he put his foot down then it'll sound bit like a scooby.. Is that the sound your getting? If so his problem was his coil pack.. If not then sorry I can't be much more help! Hope u get it sorted mate!

 

[PowellyEG]

Gops, Its intermittent mate, its fine normal smooth driving until I give it some in 2/3rd over 4k ish, then out of nowhere exhaust tone will change to a low burble / like having no back box, the only way to describe it is as above, Im asking a few local folk if they have Vag com, ill get it plugged in and try to replicate the problem whilst with the specialist.

Thanks Tuffty, im thinking this may be a specialist job, ill try and find some one local that has Vag Com.

 

[PowellyEG]

vwrescue.co.uk

midlandvw.co.uk


Both have been recommended, any one had any experience with them?

 

[Gops]

Ahh i see! well good luck! Midland VW is a good garage, my WHOLE car history (i counted almost £8k) worth of maintenance was from Midland VW and Jodi is a top guy! Where are you based mate?

 

[PowellyEG]

near J2 off the M5 Sandwell/Dudley ways.

 

[A3Tom]

Midland VW will see you right

Give them a call and get it booked in and they'll sort you out.

The problems you've got could be anything really so getting it up to Midland and scanned/checked over will save you a load of time (and money maybe!).

 

[PowellyEG]

Still havent had chance to get this checked out, in fact ive decided to sell. Ill post a FS thread up.

 

[PowellyEG]

Once again thank you so much for all your help everyone, sorry that my stay here was short lived.