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Scion tC 1G Forced Induction Turbo and supercharger applications...

Cant hit full boost

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Old Feb 18, 2009 | 04:12 AM
  #1  
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Default Cant hit full boost

Just this morning i noticed my car seemed a little off.
Checked under the hood and didnt notice anything.
I take it out to test it and this is what happens
-the car cannot hit full boost. it builds boost a little slower than normal, but will stop at around 5 psi. I have an 8lb spring in my wastegate and no boost controller.
-my boost gauge reads a little under -20 at idle (not sure if thats related)
-the wastegate isnt opening. or it isnt giving me that open dump sound anymore, obviously because im not hitting 8psi, but then why does the boost stop?
-under the hood, i dont notice any leaks, and the BOV seems to be closes all the way.

any suggestions?
Old Feb 18, 2009 | 09:07 AM
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hmmm wastegate diaphram maybe? Check all your vacuum lines see if theres a kink anywhere. see if that helps
Old Feb 18, 2009 | 01:59 PM
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x2 check vac lines, is there maybe an exhaust leak between motor and turbo? You may not notice this at idle, only under load, look for black dust around the gaskets. I'm going to say definate exhasut leak.
Old Feb 18, 2009 | 02:09 PM
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x2 I have had an exhaust leak before and built only 1 pound of boost until I figures outthe gasket was fried
Old Feb 18, 2009 | 03:29 PM
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i have a crack in my manifold and still almost build full boost...
Old Feb 18, 2009 | 04:19 PM
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yeah sounds like a vac/boost leak, check every pipes, couplers, intercooler, vacuum lines, bov, and intake manifold for cracks maybe.. i doubt its an exhaust leak unless its a really huge hole
Old Feb 18, 2009 | 04:40 PM
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I think its an exhaust leak.

Check all the vac lines, and couplers.

I think the easy way, is to have some soap and water mix in a spray bottle.

Spray the suspicious areas. Have someone rev the car slightly, and look for soap bubbles.

I think thats the ghetto way of doing it ^^ but it works.

The right way, is with pressurized air, or something like that.
Old Feb 18, 2009 | 04:45 PM
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thanks guys
ill check everything out today
Old Feb 18, 2009 | 05:53 PM
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I actually had an issue like this when the boost source line popped off the back of my boost guage.
Old Feb 19, 2009 | 01:51 AM
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intercooler piping???where is your wastegate vacuum source??? but im willing to bet money a coupler is loose
Old Feb 19, 2009 | 01:58 AM
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Originally Posted by chintastictc
intercooler piping???where is your wastegate vacuum source??? but im willing to bet money a coupler is loose

x2
Old Feb 19, 2009 | 03:17 AM
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vac leak would cause vacuum to be closer to atmosphere (zero) not negative

it can't be a vac leak only thing i can think of is a major exhaust leak, it wouldn't be spooling as fast, or a intercooler pipe loose on the hot side. that MIGHT cause a small vac leak but might not be noticable, but it WOULD cause boost to leak out
Old Feb 19, 2009 | 12:04 PM
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the only time i had a loose pipe on the hot side i blew my pipes apart, and it came with a nice loud POP!
Old Feb 19, 2009 | 06:05 PM
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when i first put on my turbo kit it would spool to like 5 psi and wont go any further...so i came to the conclusion that a couple wasnt secured and when i tightened it up more it hit full boost...it probly wont be noticable but just loosen and tighten back every IC pipe and see if it fixes
Old Feb 19, 2009 | 06:14 PM
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i think the flux capacitor isnt getting the requided 1.21 jiggawatts of power. theres where i would start.
Old Feb 19, 2009 | 06:18 PM
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Maybe you can send one of your engineers over here to the state to fix it java.

^^
Old Feb 19, 2009 | 06:21 PM
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i can try but my guys right now are busy with creating flux capacitor stage 1.5.

then its off to the coaters and god knows how long that takes. ;)
Old Feb 19, 2009 | 07:20 PM
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roflmao!
Old Feb 19, 2009 | 07:38 PM
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hahahhaa
Old Feb 20, 2009 | 05:22 AM
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I think i know whats going on. I see this crap happen all the time...... You walk out of your home to take a ride in your car and BAM! "Holy bejesus.. This is gonna be expensive..."
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