Boost leak symptoms but no boost leak found.

[sikkony]

I’ve spent about a months time back and forth in my spare time trying to fix a boost/vacuum leak kind of symptom in my car. This problem has been ongoing for a long time now, probably half a year now.

Car: GTI FSI 06 DSG

Added hardware:
• APR Stage II + (with all hardware required)
• Intake Forge Twintake
• Rev D Diverter valve
• BSH Front PCV Revamp

I’ve recently pressurized the turbo inlet (blocking the PCV rear breather hose to valve cover, oil cap off) with 20 PSI. No boost leak found from turbo outlet all the way to intake manifold. I used windex spray to find the leaks whilst the system was under pressure.

I inspected my DV once again, and it looked fine.

I don’t have VAGCOM so I can’t properly diagnose my car and find out the problems in detail.
I was hoping someone with experience or ideas could point me in the right direction before I have to spend more $ such as investing on the VAGCOM cable.

I’ve used TORQUE (Android application + OBDII reader) to log my boost (lol). I’ve attached it below:
I also logged my friend’s car, S2+ FSI GTI to see if application/reader was not reliable, but his logs came out good.

Any tips on what I should inspect next would be helpful.

-------------------------------------------------------------------------------------
Notes:
Picture 1 = Log of a pull in 2nd gear.

Picture 2 = Besides the one pull in the graph (where it peaks at 21 psi), I drove around as gentle as possible avoiding using the turbo.

 

[scdefender2]

I have the same mods as you, except im just stage 2 and i had problems for 4 months. re-occuring engine lights for an underboost code, only hitting like 13-15lbs of boost. I tried everything and finally tried going aftermarket with the diverter valve, i switched from the rev D to awe tuning diverter valve and have been engine light and problem free for over 3 months. Pulls strong!

 

[scdefender2]

i've read about the rev d even having problems when your stage 2 or stage 2+ ......

 

[chad1230]

I have the same problem but i'm Revo stage 2+. I no longer get that initial 21 psi boost spike. It starts at 16 psi and oscillates from there. im starting to think its the rev d dv...

 

[ROH ECHT]

PCV, MAF sensor, or DV - all will cause this as well.

 

[07gtinc]

im curious here im stage 2 apr but i have a bsh catch can and a forge bullet proof diverter valve but yet im still only spiking 17 psi and one pulls it holds around 12psi. thats pathetic for a stage 2 tune from what it used to be. any ideas for mine too? or let me know what you learned with yours i wish i could figure out this problem as well

 

[160hunter]

I was on Unitronic stage 2 and had the same problems as you. I had no boost leaks but the car just would not boost like it was. It ended up being a bad wastegate. Log your n75 duty cycle first to verify because changing the wastegate is a big PITA.

 

[ROH ECHT]

Do the pcv check, and then separately try unplugging the maf. If both of those are OK then pull the dv out, yes the version'D' go bad as well, and give it a look. If the w/g is bummed, IEEKS! The N75 valve is working because you are building boost so it is not that. But you do want to see where its duty cycle is running. If it stays high, near 90%+, it just tells you that it is trying to build boost. Which could be the w/g, but could also be any of the other things already mentioned where boost is lost.

Being that once there was more boost than now, It is likely - small leak, dv, pcv, maf, or hopefully not the w/g.

 

[sikkony]

or let me know what you learned with yours i wish i could figure out this problem as well

Yeah I will do each section on my car again. Will let you know which one it is that solves my problem.

I had no boost leaks but the car just would not boost like it was. It ended up being a bad wastegate. Log your n75 duty cycle first to verify because changing the wastegate is a big PITA.

I have no VAGCOM unfortunately. I will look into getting it though if I don't get this problem solved. For the W/G, did you have to remove the turbo to get to it? Did yours boost spike like mine, then hold at a much lower level like my graph?

Being that once there was more boost than now, It is likely - small leak, dv, pcv, maf, or hopefully not the w/g.

I'll go through all these three things once more just incase it is one of them. Will post up my results when I do get each one done.

Thanks to everyone else for the suggestions.

 

[160hunter]

He still needs to log the n75. If he doesn't have a boost leak and everything else checks out then logging the n75 will tell you if the wastegate is bad cause he will be maxing out the n75.

 

[madd791]

those anybody know how can i tell if my diverter version D is broken when i pull it out...what should i look for... sorry for the threat jack

 

[sikkony]

Hi, updates:

1. I just changed my DV to another DV on hand.
2. I redid my PCV system, mainly on the intake manifold block off cap (BSH Revamp kit).

Haven't cleaned MAF yet.

I noticed today whilst sitting in the car with the ignition on (engine off though), when I floor the accelerator pedal 100%, the car only reads 88.2%.

A member of this forum has offered to help me log my car with VAGCOM. I will see if I can reset the throttle body too.

I'll post the logs from VAGCOM tomorrow. Thanks for all the help so far.

 

[sikkony]

Updates:

Ok I found out my car has a misfire on cylinder 2.
I couldn't reset throttle body too... VAGCOM's command button wouldn't highlight...

 

[GTi R Enigma]

To reset throttle body do as follows. Sit in car , close door. Insert key, turn to on position, but don't start car wait about 45 secs for electronics to stop. And your done

Sent from my HTC Sensation 4G using Tapatalk

 

[sikkony]

To reset throttle body do as follows. Sit in car , close door. Insert key, turn to on position, but don't start car wait about 45 secs for electronics to stop. And your done

Sent from my HTC Sensation 4G using Tapatalk

Apparently this doesn't realign the throttle body but only resets your driving pattern the computer has recorded. I'll give it a try anyways. Thanks.