Can VCDS indicate vacuum/boost leak on MkIV Beetle?

bizzle

Veteran Member
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May 21, 2013
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TDI
2015 GSW SEL (totaled), 2013 Touareg Executive
Hi forums,

Short version of my story is that I smashed the front bumper and broke my stock intercooler. I replaced it with a FMIC. I have routed all my tubing but when I lay into the throttle I get a distinct whistle. The more I push it the higher it goes...almost near a dog whistle in pitch when I'm on the freeway passing someone.

I'm curious if I have a boost leak or possibly a vacuum leak. Can I use VCDS to diagnose this whistle? If so, can you tell me how please?
 

Uwe

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Lansdale, PA, USA
VCDS can only tell you what the car itself knows. The car MIGHT know that it has a leak, but I rather doubt it has any clue where the leak is. If you have a whistling noise, I would suggest that a stethoscope (even a home made one) is a more appropriate tool.

-Uwe-
 

bizzle

Veteran Member
Joined
May 21, 2013
Location
Southern California
TDI
2015 GSW SEL (totaled), 2013 Touareg Executive
I didn't think it would tell me which clamp is loose but I was hoping one of the boxes would be able to tell me if something was amiss. Or if it could tell me whether I have one or the other.

It's going to be difficult hanging on to the hood trying to listen for the leak with a stethoscope while someone is driving at freeway speeds :) (that's the only time I can get it to whistle).
 

JSWTDI09

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I am not certain what measuring blocks are available in a '98 Beetle, but I suspect that you can log requested and actual boost pressures. This should be able to tell you if you are losing boost somewhere in the system. However, as stated above, it can't tell you where it is happening.

Have Fun!

Don
 

Ol'Rattler

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And really, that's the thing about VCDS. It's not going to tell you everything about your engine, just what it sees. After that, it's up to you to properly diagnose the problem.

Fault code xxxx does not mean replace the component named in the text of the fault code, it means diagnose why the ECU thinks there is a problem with the component named.
 

Ol'Rattler

Top Post Dawg
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Location
PNA
TDI
2006 BRM Jetta
Does sound like a boost leak. You can check it by putting the car in 1rst and feathering the clutch to cause the engine to come up on boost while not moving with the hood open so you can observe were the leak is.

Only do this for a few second at a time so you don't fry the clutch.
 
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bizzle

Veteran Member
Joined
May 21, 2013
Location
Southern California
TDI
2015 GSW SEL (totaled), 2013 Touareg Executive
should I be looking at measuring block 011 (charge pressure control) and comparing boost specified from boost actual?

is it possible that the FMIC and the piping has amplified a normal turbo whine that I didn't hear before simply because my stock intercooler was all tucked down behind the front bumper?
 
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bizzle

Veteran Member
Joined
May 21, 2013
Location
Southern California
TDI
2015 GSW SEL (totaled), 2013 Touareg Executive
I created two line charts of two separate runs and they seem to indicate I don't have a boost leak if I'm interpreting the data correctly. I still have the noise, though. What do you think?


 
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