tuccatucca

Hi Guys ( I have this post in the C5 A6 section too, but you guys have my same motor so posting also in the S4 category out of despiration!!!) Mods if this is not cool please let me know.

As the thread title says - HELP! 2001 2.7T motor.

I have had some codes for boost leaks made more noticeable after chipping, and have pressure tested the vacuum hoses at the back of the engine (near the EGT sensors, basically under where the MAF would be)

Pressure testing has revealed a leak in the passenger side line of what I believe is the control pressure hose, running from the side of the boost control valve (N75?) through a rubber line, via a T fitting, to the hard metal lines that run down to the wastegate actuators on driver and passenger side turbos.

The issue that I have is that the top of the lines blowing / sucking on the hoses are not vacuum or pressure tight, there is a pretty noticeable leak on the passenger side - driver side is tight.

I have traced this leak through testing unfortunately to this line, but below the car, to the small short rubber section of line that goes from the hard metal line on the turbo directly to the little nipple on the wastegate actuator. You can see in the pics, its covered in some type of foil wrap I beleive to probably keep the heat from cooking the soft line. This area is kindof coated in oil and when I have someone supply air through the line with our compressor, I can actually see some of the oil droplets bubble around the end of the line kindof between the foil and the actual pressure line, so I think its the line that maybe got cooked and melted thru or cracked.

I am REALLY hoping that maybe someone has done this before on their S4 2.7T?? is this common or possible without dropping the motor? If so, how did you do it??

It looks to me like I would have to probably 1) put the nose in service position 2) take out the inlet pipe for the passenger side turbo 3) probably pull out the motor mount on the passenger side as well, just to get at this section of hose...

Does anyone know of an easier way? Thanks !!!

TGK

Haha I know how you feel! The A6 2.7t's are all going the way of old yeller. Like all things with this car, I assume it can be done with engine in, but will be nice and difficult! Good luck

BTW, at least you know where your leak is coming from! I've been chasing my craptastic leak for a year!

TGK

I'd say head over to the 2.7t section, but ahh....hmm

KarmannSport

LOL...did this line today to correct an overboost issue. It can be done but it is NOT easy. The line is about $130 from audi.

tuccatucca

Well, I have the line off, and under this foil sleeve there is a huge tear, prbly half way through the diameter of the hose. I wonder how long its been like that!

I'll be checking with the dealer to get the line since couple of the ends have a factory crimp or band style fastener from the metal to the silicone lines.

Thanks for the post!

Oh, and yeah, nose in service position so I could move the turbo inlet pipe out. Also had to drop the sway arm and the bracket and motor mount on the passenger side. Good times

KarmannSport

Yeah...thats what I did. didnt take off the motor mount though...just dropped the sway bar and remover the motor mount bracket.

tuccatucca

Alright ... so in effort to put this issue to bed here is the update, and the problem is fixed.

Here is the code that this problem was responsible for:

Tuesday, 23 November 2010, 17:11:07

VAG-COM Version: Release 409.1-S



Control Module Part Number: 4B0 907 551 AA

Component and/or Version: 2.7l V6/5VT G01 0001

Software Coding: 06712

Work Shop Code: WSC 26130

Additional Info: WAUED64B91N047196 AUZ7Z0Y1562177

1 Fault Found:

17963 - Charge Pressure: Maximum Limit Exceeded

P1555 - 35-00 - -

---------------------------------------------------------------------------





Tuesday, 23 November 2010, 17:32:59

VAG-COM Version: Release 409.1-S



Control Module Part Number: 4B0 907 551 AA

Component and/or Version: 2.7l V6/5VT G01 0001

Software Coding: 06712

Work Shop Code: WSC 26130

Additional Info: WAUED64B91N047196 AUZ7Z0Y1562177

1 Fault Found:

17963 - Charge Pressure: Maximum Limit Exceeded

P1555 - 35-00 - -

---------------------------------------------------------------------------

As you can see this code came back pretty fast after it was cleared, so this was a definite source of a significant boost leak.

This is part number 078 145 718 AA - it is the entire line, hard line, with the factory crimped / banded silicone hoses on either end. In Canada from Audi dealer (sit down guys) it takes about 10 days to get in, and it costs $275 plus tax, without installation, without a free coffee, and without aplogies neither words of encrouagement. haha

SO - needless to say - I fixed the line myself. Here is a picture of it in its torn condition, but I dont have any pics of it fixed. I basically used the same diameter silicone hose, replaced the bottom section by cutting off the factory bands with my dremel.

Then there is a tit and a nub on the end you can slip the new hose over and clamp it. I used some avaiation style high pressure fuel line clamps, and once I had this, I heat wrapped the entire section with 1500 degree resistant heat tape, and then also slipped the factory cloth heat sleeve back overtop.

Installed in the car, tested, vacuum holds beautifully. I then basically bolted the motor mount / bracket back in, sway bar, turbo inlet pipe on the pass. side, all that other good stuff. This in total took me probably 15 hours or so because of how difficult it was to access. The only way I figure I can get screwed on this is if my clamps somehow fail, but, the previous design was the same I just have one more clamp on the end that used to be factory, so I dont see it happening.

After this was done, cleared codes, checked in stock / chipped modes, all is good and happy, no codes returning and boost response feels much much better.

Also - I think our factory wastegates are set to what, 6 or 7 PSI? I'm wondering as an aside how much pressure this line actually sees.

Thanks for the verification guys, I'm sure others have been thru this before but not alot of posts about it.

B5in

Holy Shizzz I have been trying to track this same thing down for a year now. I purchased a boost leak tester and it won't hold anything past 5psi and I can hear the air leaking out behind the motor and I get the same code "P1555"

It seems like a LOT of work for just a simple line, I think I might have a pro do it. I can't believe how expensive that line is, even at ECS it's almost $200

TGK

I've hooked my mityvac upto the T fitting up top for the wastegates, I pump it to ~10 in/hg...And the vacuum slowly leaks all the way down...The vacuum should hold correct? Still can't find my source of boost loss...I'm wondering if a bad wastegate line could be my problem...

tuccatucca

I made the line myself, its wayyyyy too expensive in my opinion for simply a piece of hose. I have (knock on wood) not a single problem since repairing this line in the fashion that I did it, I think this is a good permanent fix and it cost me about $25 in parts.