Well I have a GIAC X tune in the car and I have had low boost numbers for a while so I decided to log it using vag-com and have some interesting findings... I have a lot of info that I logged so i put it all in an file for you guys to look at.

http://www.jmlpictures.com/jmldownlo...reTest_Log.xls

There is a graph also of the requested vs actual boost. Any ideas?

Josh

 

The turbos aren't on there way out are they? If not, I would imagine a boost leak. But what's up with the sudden in drop? Odd because it shows up on the Requested and Actual.

 

The car started to feel like it was missfiring so i let off the gas for a sec and then it went away.... No codes of missfires or anything either.

Josh

 

Oh ok, I was all 'wtf?!"

Well if you're turbos were making that low of boost I would imagine they'd be whining like mad. I would still say a boost leak, obvious things like leaky DV's and tears in the rubber/ silicone parts. Could be a faulty N75 valve even.

 

Ok, so I replaced my drivers side O2 which was bad (and it wasnt nearly as hard as I thought it would be! but i just went for a test drive and im still having a weird problem. Whenever I shift from 2nd to 3rd the car just doesn't want to go anymore. My boost gauge is says it's at 7-8psi but the car just doesn't go... it starts, for a lack of a better word, jerking/hesitating instead of accelerating. If I start from a 25-30mph roll in 3rd gear and just punch it the car accelerates well without any weird jerking/hesitating problems. Just still under-boost. I still think it could possibly be a boost leak but can a boost leak cause those problems too?

Also I just pulled these codes for the first time. Im hoping that the System To Rich is due to the O2 sensor being bad. I will see if that comes back now that it's replaced:

17964 - Charge Pressure Control: Negative Deviation

P1556 - 35-10 - - - Intermittent

17535 - Fuel Trim: Bank 1 (Mult): System too Rich

P1127 - 35-10 - - - Intermittent

17537 - Fuel Trim: Bank 2 (Mult): System too Rich

P1129 - 35-10 - - - Intermittent

17535 - Fuel Trim: Bank 1 (Mult): System too Rich

P1127 - 35-00 - -


Any ideas? Bad N75 causing all these problems???

Josh

 

check for boost leaks before replacing valves

 

Yeah im going to do that today.

Josh

 

Well found my boost leak!





Time for a new TBB!

josh

 

Just ordered the Samco TBB. Should be here in 3-4 days... I WANT IT SOONER!

josh

 

So i did a temp fix on the old TBB just till my new one shows up. I wrapped the part that was torn in electrical tape to try and seal it really well and put it all back together then re-pressure tested. Didn't hear any leaks so I went for a quick drive and EVERYTHING IS WORKING RIGHT! My boost is right where it should be. No more crappy shifts where it falls on it's face, and it just sounds better. Amazing what that boost leak will do to your car! HAHA. Can't wait to get the SAMCO TBB and have this problem fixed for good!

Josh