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View Full Version : Low boost. REALLY need help asap! :( **SOLVED***



adr3naline fix
01-23-2009, 05:53 PM
Ok here is the deal:

Car only boosts to 7psi....to the dot, nothing higher in any gear/rpm. (Should be hitting 18-20). Brand new VDO mechanical/manual boost gauge.

I went to try the tennis ball boost leak method, and when it got around to finding the PVC hose so I could clamp it off, I have NO IDEA where it is. There are too many damn hoses around the manifold. I pressured the system to god knows how many PSI, and watched the boost gauge, it went to a whopping 3psi MAX.

The car runs perfect. but only boosts to 7psi, in any gear. No spiking, nothing. Its like it was programed to hit 7psi.

At idle it is at 20-22 HG.

I do not own a vag-com system, nor do I know where to find someone with one.

I've only got access to a warm garage for the next 24 hours :(
heeeeeeeeeeelp!!!!!! [=(]

Seerlah
01-23-2009, 06:17 PM
The PCV pipe is the metal pipe that runs along the left side of the head/valve cover (if looking from the front of vehicle) of the engine. It will be bolted to the head of the engine. But that does not need to be clamped of when doing a boost leak test. It is the spot on the TIP where the PVC valve is (or the PCV valve itself) that needs to be closed off (as to not have any oil from the PVC pipe enter back into the TIP). What I did was get one of those rubber replacment wine bottle corks w/the little lever on top that has the rubber bottom expand (cost like .50, but the lady at the counter gave me 2 used ones for free [cool]). It fits into the valve rather snug when the lever is pulled. And it is better to use pressurised air from a tank with a gauge on it, to see how much psi is being pushed through the system. I usually set it at 15psi and keep a keen ear to any possible leaks.

adr3naline fix
01-23-2009, 06:24 PM
so I am supposed to put my hand over the end (or similar) to clog the PVC tube? it never sucked nor blew any air during testing.



also...can I unplug my N75 Valve, then if the boost rises above the 7psi I am getting right now, it may be the N75 that burnt out?

tdn
01-23-2009, 06:26 PM
Get your ass to autozone and get your code read, you probably have leaks, but I think you're in limp mode as well.

v1nyd
01-23-2009, 06:27 PM
The PCV pipe is the metal pipe that runs along the left side of the head/valve cover (if looking from the front of vehicle) of the engine. It will be bolted to the head of the engine. It is better to use pressurised air from a tank with a gauge on it, to see how much psi is being pushed through the system. I usually set it at 15psi and keep a keen ear to any possible leaks.

unless it's a fwd the information he provided you with is for a quattro (ftw [>_<])

adr3naline fix
01-23-2009, 06:43 PM
It's a quattro

Here is my N75...isnt the long end (plugged off with black piece) supposed to be plugged into the TIP?

http://i49.photobucket.com/albums/f300/oreo321321/DIGI0388.jpg

adr3naline fix
01-23-2009, 07:03 PM
Just pulled off the MAF, it was very clean.

Edit: Unplugged and ran without MAF. still would not boost past 7psi

help!!!

adr3naline fix
01-23-2009, 07:52 PM
GOT IT.

Another +1 for retarded moments. A few weeks ago I saw my N75 laying against my wastegate, melting that blocked off end in the picture. So I put that black cap on there. Come to find out via a diagram I just saw that that is the ambient pressure valve portion of the N75. So I took the cap off and viola. 18psi. Im a kid again!

AudiTurbo
01-23-2009, 08:13 PM
Good job. Why would you take the N75 valve out anyway?

adr3naline fix
01-23-2009, 08:21 PM
Good job. Why would you take the N75 valve out anyway?

Because I wanted to see if the N75 was restricting the wastegate. If you remove the N75 take away any restriction, so I could see if the boost would continue to 18psi (if it did, it was a boost leak) if it did go past 7psi, I would have replaced the N75

AudiTurbo
01-23-2009, 08:48 PM
How do you like your setup?

adr3naline fix
01-23-2009, 09:20 PM
It's pretty sick. Daily driver with the gt2871r for 15k miles, and for 10k miles before that there was a gt28rs.

Very reliable, gets good gas mileage, and quick :)

AudiTurbo
01-24-2009, 06:04 AM
I want the gt28rs... Still have yours

B5A4Kevin
01-24-2009, 07:01 AM
are you elim or full frame?

AudiTurbo
01-24-2009, 07:06 AM
Full Frame?

adr3naline fix
01-24-2009, 12:52 PM
I want the gt28rs... Still have yours

Nah that is long gone, sorry. They are pretty inexpensive though.


are you elim or full frame?

It is the full GT2871R.