beginner dsm'er GST issue

[99gstturbo]

Hi guys,
I recently purchased a 99 GST. When I purchased it the car had a few mods. Currently the car has a 3" exhaust from the downpipe back. Turbo smart bov manuel boost controller set to 11 psi. Stock t25 turbo. The issue I'm having is that when brought above 4500 rpms I hit a brick wall where I'm hitting fuel cut. My issue is I'm over boosting like crazy. Controller set to 11psi. My aftermarket boost gauge is telling me its boosting to 23 psi. I've check for boost leaks and no leaks. Any thoughts or help would be greatly appreciated.
Thanks in advance.

 

[95gsxxx]

first thing i would check is the vacuum line from the intake manifold to the wastegate, make sure it isnt broken/ripped that would cause a false reading of psi and the wastegate will stay closed causing overboost

 

[Insane20]

Sounds like a faulty boost controller, take out the boost controller and run waste gate pressure until you get another.

 

[2g spyder eclipse]

Sounds like you might have the MBC hooked up all wompus kitty.

 

[lasershark]

kinda sounds like boost creep

 

[99gstturbo]

I didn't hook it up. It came to me like that . It looks like a cheap eBay controller. Gonna change it out when I get the chance.

 

[dharrison]

i would rerun some new vaccum lines to all the components in your system. stuff is very cheap and easy to do

 

[1G Eclipse94928]

I didn't hook it up. It came to me like that . It looks like a cheap eBay controller. Gonna change it out when I get the chance.

no... Like people already said remove it and just loop the lines to each other and see if that fixes it. If it doesn't you need to do a BOOST LEAK TEST.

 

[lasershark]

take off the MBC, hook up wastegate to stock and do a couple of pulls if you still get boost spikes then you are creeping, if not good, do what the others have suggested

 

[1G Eclipse94928]

take off the MBC, hook up wastegate to stock and do a couple of pulls if you still get boost spikes then you are creeping, if not good, do what the others have suggested

The waste gate vacuum stays the same and shouldn't be T'd into.

 

[lasershark]

The waste gate vacuum stays the same and shouldn't be T'd into.

take it off and return it to stock is what I was getting at, Don't really know why anyone would ever t into the wastegate for anything other than a boost control device. Are you confused with something I said?

back on point to the op you should make sure your waste-gate isn't suck closed, while you are checking things out

 

[simplejoe]

If it's this one [ame=http://m.ebay.com/itm/221258437583?nav=SEARCH]Universal 1 30 PSI Manual Adjustable Turbo Boost Controller Kit Red | eBay[/ame]. Throw it away. My car came with one and it did the same thing. I messed with it so much trying to get it right and it's just junk.

 

[99gstturbo]

Nope simple Joe that's not it. I took out the MBC and ran it off the wastegate. Boosts to 14 psi then settle down to 11psi. Looks like boost controller was crap which I kinda figured. Already ordered a Hallman pro boost controller.

 

[ultimta]

consider a new BOV if you plan on running more than wastegate boost.
Stock 2g bypass valves tend to leak somewhere around the mid teens sometimes less if Im not mistaken. A crushed 1g BOV should be enough

 

[99gstturbo]

Ultima I don't have a stock 2g bov. The front mount I bought is flanged for a 1g.

 

[John_M93]

im a revive this thread if y'all don't mind
I just installed a used OEM t25 idle after a rev the Rpms stay at about 3,000
I try to bring the rpms up and it'll back fire and bog down.
The turbo smart boost controller that was installed by previous owner was stuck and had to kinda pry up for it to turn

 

[lasershark]

im a revive this thread if y'all don't mind
I just installed a used OEM t25 idle after a rev the Rpms stay at about 3,000
I try to bring the rpms up and it'll back fire and bog down.
The turbo smart boost controller that was installed by previous owner was stuck and had to kinda pry up for it to turn

Have you checked for boost leaks first?

 

[John_M93]

Found stock waste gate stuck like chuck
I replaced with another known good one.
It drove great for a little while but now it's back to the bogging down
I have not checked for boost leaks yet