A3 1.8T AGU - Few Questions

[Scottie7]

Hi All,

First of all let me first say I've been through the stickies and I still have a couple of questions, and secondly I've been around Audi's for a long time, 2.5 V6's TDI's VR6's 4Mo's etc in a previous life I had a nice 2.5 v6 TDI running close to 300BHP i know Audi's to a degree. However this my first petrol Audi turbo, I've done some work on these before but not enough to know enough in my opinion, also I am not in the UK anymore.

So i have a 1.8t AGU engine, with what i am assuming is still running the stock K03 turbo, however the person i bought this of said it had been "revised".

From what I can see the AGU has no MAP sensor, and appears to have the least amount of vacuum lines out of all these 1.8t's.

I am not looking for huge power, just reliability. I've picked up a thermostat this week as the car will not get to 90c etc.

AC fuse by the battery had melted and that was a quick fix, to get the AC back up and running.

All in the all the car drives well, pulls hard to the redline and boosts well from what i can tell, actually a little surprised about how quick it was for a 150BHP, car has 108,000KM on the clock.

I am going to weld up the clutch pedal plate soon as I've experienced the awful *PING* "what just went flying past my head" *clutch pedal on the floor scenario in my 4Mo*.

Anyway on to my questions:

1. The car idles just fine, however takes a little while to find the idle sometimes almost like its a little ****** and trying to point at 900rpm and misses to 1100rpm and 700rpm till it finds it, its pretty random, a "none car person" probably wouldn't notice it.

2. The car has a noise of what i can only assume is a vacuum leak, at idle and lowish revs - here's a video:
https://photos.app.goo.gl/PEuhP77eLLlellik2 You can hear I am blipping the throttle to change the sound, this isn't the car idling. I am struggling to find it with the limited tools I have right now.

3. The car can lurch a little bit on and off the throttle, more so when cold, again its not massively noticeable.

4. I have some questions about deleting vacuum lines and how this affects the car in terms of its refinement and daily drive-ability, not to mention health for of the turbo, i am struggling to find a guide that is for the AGU and what does and doesn't apply, I don't need a full tutorial but some advice would be great.

And obviously can't start a thread without a picture of the car in question:

Any help would be great, Cheers.

 

[Warsuperior]

fix leaks in system and most problems you descriped should go away.
Few ways to find leaks in intake system: use car cold start spray, leak and idle goes up or car chokes. Some use smoke test on pipes to see where smoke comes out.

Clean your throttle body and do adaptation, this will fix most likely idle too. Adaptation can be done without any tools. Open up hood, put ignition on but dont start. Wait 3min approx. DONT TOUCH GAS PEDAL!

This is helpful too if you ever run out of battery. Usually after embty battery car might start but doesnt rev=do adaptation.
3. "can lurch" what do you mean by that? sorry Im not native english

Dont touch vacuum lines unless you have something broken and dont want to replace

I dont hear anything wrong in video, sounds pretty much same as my a3 agu engine.

AGU doesnt have map, it uses MAF, IAT etc.
AGU engines have M3.8.2 or M3.8.3 engine management.

I have very good tune program for that engine. Really makes big difference how it acts. I calculated by air flow that should have 171whp or near 190hp from engine.
With this tune I have driven over 60 000km without problems. If you are interested about tune, please PM me.
AGU m3.8.x needs to bench flashed since it misses 12v pin from OBD

 

[Scottie7]

Hi Mate,

thanks for taking the time to reply,

Since I've picked up the car i have engine wise i have:

changed the thermostat
properly flushed coolant
cleaned MAF
cleaned TB sensor
swapped a vacuum line and added clamps where missing.
TB off and cleaned w/ new gasket.
sealed the diptick

All fluids are clean, ill do a oil change at some point soon.

Your tip on the adaption / re calibration of the throttle body was a good one, I am not sure if its perfect or not, and if i am honest i left the car and came back 10 minutes later and done something else, i didn't listen for calibration, but the car drives better, especially between the gears the revs don't drop like a stone anymore, making for much better changes, also the car was extremely dead under 1.5k. I always assumed i'd need vag-com for this one, the car recently had a new battery so i knew the TB would be all over the show, so taking it off and cleaning couldn't do much harm.

I'll pick up some vag-com soon and see whats what.

("Lurch" is when you lift off the throttle and its not smooth)

In regards to the video i was talking about the high pitched noise, doesn't seem normal to me.

Cheers,

 

[Warsuperior]

You dont have to listen to calibration. It does it on its own and you cannot do anything to change it different so its "perfect" always.
If you change battery, car usually loses the TB adaptation, same with low voltage.

That high pitched noise is most likely your altenator, mine does same noise and its altenator whine. Cannot be 100% certain since so lot other noises on video too. Nothing to be worried about really.
Otherwise your car sounds almost 100% same as mine.

Change spark plugs if they have lot of mileage, could help getting smoother idle and stop "lurch"

 

[Scottie7]

Cheers. It's tricky to tell when I have more time I'll try and find the noise, pull the aux belt and bits and pieces see where i get.

Have you removed the evac system or any other parts of the vacuum lines?
Plugs are on the list along with filters etc.

 

[Warsuperior]

nope, my car is 100% original condition, except for tune.
AGU has pretty simple vacuum system so I kept it original.

 

[Scottie7]

I would tend to agree with you on that one.

Cheers