Air Intake Leak

Gts2811

2.0tdi S-line Quattro
Guys, need some help/pointers.

Audi A3 2007 2.0tdi Quattro (170 bmn)

I've got an intermittent air intake leak that's breaking my heart.

In recent weeks I've replaced the following, some by advise from garage.

Intake manifold (fitted bkd one from darkside)
Both lower boost hoses (1 was defo burst)
MAP sensor
Used forte system cleaner
And wynns turbo cleaner

Yet I still have this problem, air intake leak.

When this happens the coil light flashes and sometimes the EML comes on.

This morning car was fine , then after football got most of the way home then it jumped back into limp mode.
Noticed when it's going to do this it gets hesitation around 2000rpm sometimes pushes through it, sometimes not.
Also noticed that in the morning sometimes I get to work ok, then it pops up before I leave the car park going home.

Used easy start around all air lines etc, no up take in the revs to give an indication.

And only seems to happen when engine under load, ie I can sit at the house and rev to 3k rpm and it doesn't register the leak.

When running ok, turbo seems to spool ok and it pulls like a train.

Initially this only came about around 5/6 weeks ago, I noticed when swinging a left turn the coil light flashed, then when straightened up all was ok.

Is there something I'm missing ?
Or anyone seen/heard this before ?

Apologises, I know this is a long post. And thanks for taking the time to read if you get to here.
 

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NHN

Retrofitter - Audi - VW - Skoda - Seat
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VCDS Map User
I would try using vcds aswell to be sure.

Pressure test the intake system with a smoke machine, when warm intake likes become more supple hence allows the smallest of holes to open up whereas cold they're rigid imho.
 

Gts2811

2.0tdi S-line Quattro
got it going into DH Automotive in Falkirk on Wednesday, hopefully Dave there finds the problem
 

NHN

Retrofitter - Audi - VW - Skoda - Seat
Site Sponsor
VCDS Map User
Report back with the solution ;)
 

doce

Registered User
First and before any replacement, check the wiring of the map sensor. It can be broken wire deep in insulation.
 

Gts2811

2.0tdi S-line Quattro
First and before any replacement, check the wiring of the map sensor. It can be broken wire deep in insulation.

Thought about a poor connection, but the old sensor was giving crazy readings(flat lining). New sensor seems to be providing more stable readings
 

Gts2811

2.0tdi S-line Quattro
Update guys.

Just picked car up from garage, told it's my turbo actuator that's not holding a vacuum.

Recommended to replace the turbo unit. Price is costly, around £1000 .

Can the actuator be replaced on it's own ?

Seen a few youtube vids suggesting so, but that's with the turbo out.

Can this be done with the turbo in place ?

And does anyone know the part number for the actuator ?
 

doce

Registered User
I don't know is it possible on TDI but one guy actually fixed actuator on 1.4 tsi caxa himself. Look at this video from 18min 40sec.

 

Gts2811

2.0tdi S-line Quattro
Been a while, but car is just only now fixed so thought I'd give an update on this 4 month drama .
Bit long winded, so please bear with me.

1st garage
Said it was the intake manifold (leaking), replaced - didn't fix it.
Back and forward with no results.
Inbetween this, the following were replaced.
2 x lower boost hoses
MAP sensor

2nd garage
Said it was my turbo actuator and that I needed a new turbo as you cant replace the actuator. (Cost £1000 parts and labour)

3rd garage (turns out I knew the guy) the following were replaced.
Turbo actuator (defo not holding vacuum)
And can be replaced !!!
boost hose near turbo (was starting to fail)
N75 valve

Still this problem persisted.

Back to 3rd garage, and a fair bit of head scratching.
Egr valve - replaced.
Still the problem persisted, granted with every replacement things got a little better. Although when turning left (where this whole problem started) bang, back into limp mode.

More investigating.....

Eureka. ....
Theres a broken wire that runs down to the plug of the MAP sensor.

Kinda explains why everytime the car was plugged in it would say air intake leak and a poor reading from the MAP sensor even after being replaced, although this could easily be confused with that being the sensor that's picking up that theres an issue.

So there it is....problem now fixed
 

nluk100

Registered User
Lol, didn't you read post #6? Would of saved you a fortune in time and money. Both MAF (on the petrols) and MAP sensor wiring seem to fail on these cars.
 

doce

Registered User
Unfortunately, I also made a similar mistake. In the end I fixed the problem myself as I advised in post #6.
 
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