spaz1

iTrader: (9)

Hey Guys, I am having an issue with my car. It was boosting 11psi, I blew a seam on the plenumn box. It would only boost 3psi in 1st and 2nd. and about 7psi in 3rd. It won't even open the wastgate anymore. I got it welded and problem was solved for a while now same problem is happening with low boost.. I pressure checked the system and not seeing any leaks. What could it be. I took the air filter off and the fins on the compressor side of the turbo look ok, there is very little play in the shaft and it spins nice and smooth and freely. Is it poss I over spun the turbo and damaged it somehow I haven't looked at the exhaust trubine yet. The car runs fine no missing or anything just not making boost like it used to. Before the car would spool to 11psi by 3600rpm and now it sucks...
Any Ideas would be great.
Thanks.

OUTLAWZ RACING

iTrader: (9)

What plenum box? I can only guess a leak.

koolaid_kid

iTrader: (21)

Do you have a 2 stage boost controller? If not, what is the wastegate set to?

spaz1

iTrader: (9)

I am running the pro charger twin intercooler setup. I checked for leaks. I capped off the pipe that attaches to the turbo and put a fitting in it and ran compressed air into the system it was reading 5psi on my gauge and then felt all the connections and piping for leaks. I can pull the vacuum line off the waste gate to ensure it doesn't have a signal to open and it doesn't make a difference.

87silverbullet

iTrader: (11)

Did you check your whole exhaust system? I had the same issue on my GN and the header was cracked, not giving enough exhaust to the turbo and the most I would see was 13 psi when I had it set to 25 psi. Check your exhaust and get back with us.

spaz1

iTrader: (9)

No exhaust leaks. So I guess next step is pull the turbo off and apart. Not sure what goes wrong with these things.

1BAD_LS1

iTrader: (36)

I wouldn't pull that turbo apart! Special tools are required to reassemble it! It would suck if nothing was wrong with it and you had to pay to have it re-assembled!

Check your BOV, WG, boost controller, ect.... first!

spaz1

iTrader: (9)

I have the wg blocked off with a plate. no difference. Had someone plug off muffler and went along all the exhaust checking for leaks with car reved to about 1200, none. looked at exaust not seeing any cracked manifolds and sounds same as before. Took bov out of system no difference. I can't think of anything else. Car runs fine just not boosting properly.

koolaid_kid

iTrader: (21)

I had a similar problem, turned out to be the STS dual boost controller. Found out how to rebuild it (on the web) and it is fine now, makes up to 14 pounds of boost. Just a thought.

spaz1

iTrader: (9)

I have the wastegate blocked off so all the exhaust has to go through the turbo.

1BAD_LS1

iTrader: (36)

is your boost guage hooked up correctly? lol, had to ask

make sure the turbo spins freely and check for shaft play man....

I wouldn't tear it apart myself, if your convinced thats the problem take it to a shop!

sslateron

Did you get it professionally installed?

IKnowtheFuture

iTrader: (5)

leak on the intake side me thinks. you have enuff air flowing at larger load to compensate and you get more boost in 3rd. maybe hook it up and check all your PIDs

spaz1

iTrader: (9)

I installed it. It was working fine for over 2 years..

I checked for leaks everwhere and then I checked again. I think it has to be either the turbo or the engine. NOt sure how the engine can be running so well and be the issue. And the turbo looks ok and feels ok so I don't know how this can be the issue but I am out of Ideas.

3800SII

I had a similar problem. The Wastegate ended up being the culprit. If you are vented to atmosphere then check the valve in the WG outlet.

87silverbullet

iTrader: (11)

^^^ He blocked off the wastegate and there were no leaks.

To the original poster, you stated plugged the exhaust and had the car at 1200 rpms and you found no leaks. Well I would think the car wouldn't run too long if everything was tight but if the car ran for awhile then you might have an exhaust leak.

Did you try another boost gauge? Where do you have the boost gauge connected? Is it a vacuum hose mechanical gauge or an electrical sending unit style boost gauge? Do you feel a loss of power or is it running strong like it was on 11 lbs of boost.

spaz1

iTrader: (9)

The Car is a stone now. I know it isn't making boost like it used to. The Gauge is hooked up to the intake manifold. Just had someone block off tail pipe with a piece of wood and a rag not air tight and went under the car feeling along all the exhaust piping right up to the manifolds.