# Losing boost... Bad PCV? Boost Leak? DV Shot?



## Shawninho (Nov 16, 2011)

So the other day I started noticing that I'm not boosting as much as I should be. Running APR stage 1 93 on my '02 180qc with 70K. I used to spike to about 19 and hold steady at 16-17. Now, I've been spiking to 13 and holding at 10-11. Before the chip, I would spike to maybe 11 and hold at 9. 

The change was fairly sudden. There wasn't a gradual reduction in the amount of boost I could hold. Just seemed like it started happening one day and after about 2 weeks that's where it stands. The car has also recently thrown a P0420 code, but I doubt they are related. Recently replaced the battery but I am still able to select the program via CC stalk. 

Before I start to diagnose, I was just wondering if anyone has had a similar problem. Not sure what would be most consistent with my symptoms. I've read a bad PCV valve could cause it, my DV could be shot (it's stock), or that the K03 is just running out of steam (for 70K, I really hope not). Boost leak could be the culprit too. What seems most probable?


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## 20v master (May 7, 2009)

Probability has nothing to do with it. Pressure test for boost leaks.


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## warranty225cpe (Dec 3, 2008)

20v master said:


> Probability has nothing to do with it. Pressure test for boost leaks.


This. Then reset the ecu, check for codes.


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## 20v master (May 7, 2009)

warranty225cpe said:


> This. Then reset the ecu, check for codes.


If he resets, there won't be any codes. You guys put way too much into clearing codes and resetting the ECU.


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## Shawninho (Nov 16, 2011)

I just scanned last night and the only code thrown is the P0420 -- Catalyst Efficiency Below Threshold Bank 1. We could probably have a whole other conversation about that code alone. Regardless, I don't think that code would cause the car to run more "limp."


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## warranty225cpe (Dec 3, 2008)

20v master said:


> If he resets, there won't be any codes. You guys put way too much into clearing codes and resetting the ECU.


Nah, I mentions that because if it is the dv he might be throwing a code for it. And I always rest the ecu after I fix a leak. I've always been under the impression that the ecu will adapt to the new fixes quicker than if you just drove around and let the ecu adjust to the differences.


:middlefinger:


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## 20v master (May 7, 2009)

warranty225cpe said:


> I've always been under the impression that the ecu will adapt to the new fixes quicker than if you just drove around and let the ecu adjust to the differences.
> 
> 
> :middlefinger:


It adapts at the same rate all the time. Think about it. Why would it adapt quicker in certain circumstances? If quicker adaptation was better sometimes, it'd be better all the time. :middlefingerback:


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## warranty225cpe (Dec 3, 2008)

20v master said:


> It adapts at the same rate all the time. Think about it. Why would it adapt quicker in certain circumstances? If quicker adaptation was better sometimes, it'd be better all the time. :middlefingerback:


Lol

Because you would be resetting the ecu back to stock settings. Rather than letting your ecu adapt and get rid of the changes made by running with boost leaks/issues.


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## 20v master (May 7, 2009)

warranty225cpe said:


> Lol
> 
> Because you would be resetting the ecu back to stock settings. Rather than letting your ecu adapt and get rid of the changes made by running with boost leaks/issues.


The "distance" it has to adapt to get to a good running condition doesn't affect how long it takes to get there. :thumbup: You're overthinking things.


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## EuroSpic_TT (Apr 24, 2012)

before you do anything check for boost leaks then come back with results


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## warranty225cpe (Dec 3, 2008)

20v master said:


> The "distance" it has to adapt to get to a good running condition doesn't affect how long it takes to get there. :thumbup: You're overthinking things.


:halfamiddlefinger:


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## Shawninho (Nov 16, 2011)

I put it back into stock mode and I'm getting the same psi levels. Yet I can still switch programs, is it possible the switch isn't actually happening?


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## warranty225cpe (Dec 3, 2008)

Shawninho said:


> I put it back into stock mode and I'm getting the same psi levels. Yet I can still switch programs, is it possible the switch isn't actually happening?


Doubtful. Pressure test.


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## deepblueT (Jan 26, 2008)

do you still have your PCV system under the intake manifold? check there if you do, i had some pretty bad failures under there before i did the delete. anything wierd with your brake pedal? stiff after sitting off? i had both the one way valves for the brake booster system melt open causing issues on both sides...vacuum and boost...


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## Shawninho (Nov 16, 2011)

I don't have a pressure tester (probably something worth having though) so after diagnosing some more, I replaced my DV and "upgraded" to the 710N. No noticeable changes in my problem, but after looking around some more I found a crack in an old vac line coming off of the manifold to the FPR, where I tee'ed off for the boost gauge. Anyone have links to any good vac line kits? I think a full replacement for the entire system - PCV and all - is long overdue. 

Anyways, boost is back up to normal levels. :thumbup:


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## deepblueT (Jan 26, 2008)

www.votionspeed.com 

i got a "shop kit" off of the ebay store part of the site...way more hose than i needed 4 sizes! 3 colors red, blue, or black. i chose blue!


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