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auh
04-05-2013, 01:17 PM
I'm not sure what my problem could be here. I chipped my car about 6 months ago, and noticed this problem the day after I put it back together.

My first test drive after the chip and my car over boosted at 30+psi and blow off my intercooler hoses, so my drive home from my garage was an easy one. The next day it started doing this, at low RPMs when my turbo spools up it bounces from 16-19psi. At high RPMs my car sits at about 15psi. I changed the N75 with one and it worked normal for a few days and my problem developed again. Changed it with another N75 valve out of a junk yard and I still had my problem. Eventually I upgraded my N75 to the N75E valve. Once again, my problem went away for about 3 hours and came back.

I thought maybe with my chip and K04 it was hard on the valve so I installed a manual boost controller parallel with the N75 right before I changed the N75 for the last time. Didn't make a difference.

A few days ago I got a CEL and pulled out my vagcom to see its a 17963 - Charge Pressure: Maximum Limit Exceeded P1555 - 35-10 - - - Intermittent. My car though is still boosting the exact same as before, if its going into limp mode its not doing a very good job of keeping my turbo from spooling.

Any thoughts?

auh
04-05-2013, 02:57 PM
Here is a video of what it's doing

http://youtu.be/sCEUqFkAAc0

auh
04-07-2013, 07:59 PM
Bump

auh
04-11-2013, 03:59 AM
Still no one?

Avant Nate
04-11-2013, 11:26 AM
Whens the last time you did a boost leak test? And hows your 710n?

auh
04-11-2013, 11:52 AM
710n is a little over a year old and I need to do a boost leak test

Tanzimur
04-11-2013, 11:59 AM
ye or bad 02... http://www.youtube.com/watch?NR=1&v=OHRGY3SuFIw&feature=endscreen

auh
04-11-2013, 01:36 PM
Interesting, wonder why the O2 would do that. I don't have any CEL from a bad O2 though.

Tanzimur
04-11-2013, 01:40 PM
ye same here i was like wtf. bu the 02 tells the air ratio mixture with the computer and that plays a big roll in what seems to be your isue or a fcked up wastegate acutator

auh
05-12-2013, 07:24 PM
Think I finally found my problem! I was driving yesterday and floored it while pulling out of a parking lot into traffic and one of the aluminum tubes that goes from the turbo to the intercooler popped off. I somehow worked it back on with my lack of tools in my car and babied it home to my garage. I took everything apart and tightened up all my loose connections and noticed the tube that goes from the 710n to the intercooler line shifted and was rubbing against one of my pulleys. My car is holding a ton of boost again but is still jumping a little in psi. I bet one I replace and relocate that tube my problem will go away.

QuattroGinger
05-13-2013, 03:23 AM
glad to hear u found it.

auh
05-14-2013, 09:38 AM
Replaces tubes from 710n to intercooler pipes with no luck, but I got another crazy idea that I've overlooked for a long time. When I installed my boost gauge I noticed immediately a kinda buzzed/rattling noise. I could never tell where exactly it came from and when I was looking under my hood yesterday it hit me to check to see if the vacuum lines could be an issue. Sure enough that rattling buzz sound is an issue with boost gauges.

When my boost gauge came in I was so eager to install it I just bought the first plastic tubing I could get my hands on. I just used the basic clear plastic tubing and when I checked it yesterday it was VERY weak and flimsy anywhere that engine heat could have gotten to it. It was soft enough that it could easily pinch itself shut under vacuum and have a hole open up with boost. I guess I should have known "do it right or do it twice."

I just ordered a tube kit from 42draftdesigns that comes with their special t valve. Hopefully this might fix my problem.

auh
06-18-2014, 07:31 AM
Bump because this is annoying. I just came bank from being out of the country for 7 months and was so exhumed to get behind the when of my beloved audi. Sure enough the moment I get going I remembered this problem. Last year I did checked my system for leaks, but didn't find any. I'll have to check again. Anyone else have any ideas?