little boost problem

[memphiss13]

everything has been working great up until today. i decided to try to crank the boost up a bit with my profec b. i had the high boost setting at 12psi and today i went for 14psi. but then it wouldn't hold it. boost was falling to about 10psi. now even at 12psi it still won't hold boost. it will hit 12psi and then fall.

[Bill Roberts]

Three possiblities:

One, you may have dislodged some carbon and now your flow is disruped.

Two, you developed a vacuum leak.

Three, Your wastegate is not closing properly.


Anyone think of others?? Gaskets, connection at the intercooler, a clamp that vibrated loose causeing air leaks...BOV?


One way or another, look at leaking air flow or disrupted air flow..or even a faulty line to the boost gauge.

[memphiss13]

yeah i was thinking more like a boost leak in the IC piping connections still need to check it. i tightened up the BOV a bit and that wasn't it. i'm going to go through and check it all tomorrow. hopefully its all ok.

[Bill Roberts]

Let us know your findings..If you got to try some of that knarly silver duct tape on the intercooler pipe, go for it..or the gray S Hit for kicks.

My vibe is that the extra boost caused a leak...you got to track it down. Don't let this thread die, please let us know what the deal is...since all can learn..

[memphiss13]

ok i have checked all IC pipes, played with my boost controller and everything. still no difference. boost will go up to whatever i set it to.(12 or 14psi) and then fall to 10psi. it holds 7psi no problem. what could this be? if its a gasket leaking wouldn't it leak always? not just when its above 10psi. could it be a wastegate problem? or even worse, a bad turbo? i just don't understand why it will hit the desired boost level but at about 5k it has made it down to 10psi and will hold that steady.

[kandyflip445]

*stab in the dark* Weak wastegate spring???:confused:

[memphiss13]

that was something i was thinking too. might be time for an HKS wastegate. just want to rule out anything else before i do that.

[Bill Roberts]

As screwey as this sounds....even at idle and someone juicing it slightly, their is a neat way to detect a leak.

Take a 6 foot section of garden hose and place it close to the joints and put the other end near your ear (very close..not too close as it can be LOUD) For safety sakes, stay away from moving parts :) and listen for any strange hissing sounds.

I feel that perhaps the gaskets have failed.

I metioned at first as well, wastgate not sealing...some debris.
Once you find the leak (or leaks) then make sure you reinforce the crap out of the new seal. The exhaust side is usually the culpret as in the heat destroys sheite..

Keep us informed.

The hose is a poor mans stethescope and works wonders for pinpointing problems...you can hear indivgual valves with that damned thing..

[tiki240]

did you find anything mines doing the same things only i run stck boost 7psi and mine falls to 5 psi.

[Joel 180]

what turbo do you have? T25g cannot hold more than 10-12psi over the whole rev range