little boost/bad vac/big problem

[afmafia]

i drove my car last night it was fine drove smooth at like 15lbs, i drove it again like an hour later and car only went to 10 lbs. its weird when i start it up it feels like it wants to stall untill i give it gas . it will idle at 20 vac then when i push it to go in to boost it goes to 25 vac them trys to go in to boost . to be honest the car feels real slugish it wont go past 6 psi. i took off the hose on the wastegate to the boost controller and the boost still doesnt change . what do u guys think is wrong any help is appreshated ps im using a 3 bar map sensor .

[goldollar]

Is it breaking up at at 6psi or does it have a smooth transition and wont go pas 6 pounds?

[afmafia]

its breaking up now it wont go past 4-5 lbs . when its in boost its not smooth . i think the turbo is broken . its a prescion sc50 its only about 2-3 weeks old . some people say it can have a bad center cartridge ?????? what do u guys think????

[virus77]

boost leak in your intercooler piping

[afmafia]

i checked the piping theres no leaks

[virus77]

Are you sure, just yesterday my car starting sputtering and running bad after 7 psi. I pressure tested teh system with a boost leak tester and after 7 psi a small rip in my coupler would open due to the presure and then start leaking, the car drives fine otherwise since the rip only gets exposed under boost, if you havent pressure tested your system then you should give it a shot, just a thought.

[afmafia]

my car wont go to 7lbs it will only go up to 4-5 lbs f boost and it struggle s to go to that presure level . one guy said it might me my wategate who know s ?????

[virus77]

How did you check for leaks in your pipes, I dont want to beat a dead horse with this, but often people have a boost leak that they think is fine. If it was your wastegate the car wouldnt stumble. What you are describing is very similiar to a boost leak which is an easy fix, rule that out before you go changing your turbo or whatnot.

[afmafia]

i checked all my couplers no rips or tears

[Nowhere]

You need to "PRESSURE TEST" your plumbing. A visual inspection will not show pressure leaks (duhh, rip, tear, blown hose.. Won't show little stuff).

PRESSURE test it...

Try boosting with NO air filter... post back..

[got2b240]

dude your actuator for your wastegate might be stuck open

[Nowhere]

If it was your wastegate the car wouldnt stumble.

[virus77]

still got my money on boost leak, if you are just "looking" for it you are not going to find it. Let me make this easy for you, I have my boost leak tester in a sticky on the KAT forum, infact here it is:zerothread?id=113785

Let me know if there is something you dont understand about the procedure, use it and report back.

You should try taking off the filter and driving the car, its a pretty easy test. If its an extremely diry filter that just absoluty sucks donkey nuts it will hold you from boosting, but I doubt its the case.

[afmafia]

turbos comming off tomm im going to check to see if the valve on the wastegate is ok

[virus77]

wastegate wont do what you are describing but go ahead, why dont you pull the head off the car and pull the transmission while your at it and just cause alot of work for yourself for no reason.

[Nowhere]

turbos comming off tomm im going to check to see if the valve on the wastegate is ok

Omg! My headlights don't come on, should I replace all the windows in the car?? ha..

As stated MANY times above, a stuck/etc wastgate will not cause a studder..

On my ca18det clip, my turbo is WASTED!! The shaft has like 2" of play!! The engine idles and revs PERFECTLY.. Forget about the turbo, you've got an air leak.

Sheesh..

[Nowhere]

I took off the hose on the wastegate to the boost controller and the boost still doesnt change .

Your post shows your wastegate is not a problem. If the engine has no idea what amount of air is going in, it's going to freak out, of course it's not going to boost..

A car with a bad turbo should rev and idle perfectly (in neutral/startup)..

[afmafia]

guys i think i found the problem i took off my manfold and turbo and come to find out one of the two bolts on my tial wastegate fell off i dunno how that can creat esuch a boost leak the opening from the bolt not being there is like a sliver what do u guys think ???

[Nowhere]

An EXHAUST leak should not cause the car to run rough, hard starts, etc, even if it's on the waste gate..

[afmafia]

guys it was the wastegate . i thought it was the turbo oh well . i didnt get to drive the car for 2 weeks but in that time i upgraded to a peak boost manifold . thanks huys for all your help