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FUEL CUT FOR REAL 30+lbs of boost

yeti

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Oct 13, 2010
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803
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san diego california
So after fixing all the boost leaks (still not all of them the jpipe, idle adjustment screw. And probably the throttle body)

Anyways took it for a quik spin around the block a few times (after letting it warm)
I was hitting 30+ lbs of boost and then slamming I would boost for about 5 seconds and then hit what I think to be fuel cut.

Could the minor leaks be causing the overboost?

The car still stalls at stop with no throttle it has symptoms of the "Hot start"(where the idle is as low as possible enough To start shaking sh*t)

I had the link to it does anybody know which web page I'm talking about.
 
Last edited:

TylerAdamson

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Dec 26, 2007
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1,034
Location
Iowa City, Iowa
Probably a stupid question, but do you have a boost controller on the car?
 

Barnes

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Feb 9, 2003
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Richland, WA
You need to put brand new vacuum line from the wastegate actuator directly do the nipple on the turbo outlet pipe. Or some other pressure source like the intake manifold.
 

Barnes

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Point is, you need to completely bypass all of that. Get some new vacuum hose and connect it directly from the outlet pipe to the wastegate. If you over boost, you have a bad wastegate actuator.
 

Barnes

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Yes, you can replace just the wastegate actuator. It is relatively easy too. What happens is the rubber diaphragm inside ruptures, and it will never open. So your wastegate is always closed and you get maximum boost.
 

yeti

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san diego california
Will do the vacuum line asap but I'm afraid to drive it.
The ecu will impose fuel cut before any damage happends though right?
 

Barnes

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Just drive real easy on the gas and you'll be fine.
 

yeti

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san diego california
Connected the turbo outlet pipe directely to the WGA and still boost 20lbs

Will a cheap ebay wga not be good to use here?
If not any recommendations on a cheap good one?

And anyone got pictures of which bolts I undo I know its two bolts and a pin, the pin is what more of confuses me
 

Barnes

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Just to double check a few things: What modifications do you have, if any? Particularly, do you have an aftermarket exhaust? I want to confirm this isn't boost creep.

Also, I recommend removing the wastegate actuator and testing it to confirm it is bad. Remove the two bolts that hold the wastegate actuator on. Then remove the little pin that holds the wastegate actuator rod to the wastegate flapper arm (the part that opens and closes inside the turbine housing). It might be kinda hard to do with the radiator in.

After it is out, hook up a little hose to an air compressor and apply 15psi, or something small to the wastegate actuator nipple. On a properly working actuator the rod would move out. In a bad one, the rod won't move and you will feel/hear air rushing out where the rod goes into the big round part.

AND as a triple check (if there is any doubt), after you remove the wastegate actuator, plug the vaccuum line that was attached to it. Then go drive the car without the wastegate actuator. You should have almost no boost, or take a REALLY long time for the turbo to spool, and it should never hit the boost levels you are talking about.
 

yeti

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Oct 13, 2010
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803
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san diego california
After the WGA is off if its broken can I just leave it off or should I put it back on.
I think I will put it back so I don't lose nothing

And I really appreciate all the details you are instructing me to do.
Thanks
 

Barnes

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Quoting yeti:
Oh and ya I have a 3 inch exhaust with a cat back
I think..heh



Hmm, might be boost creep. Does your boost go up to a certain point, then start to gain as you get higher in the RPMs? Or does it shoot straight to a really high number?
 

yeti

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Oct 13, 2010
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san diego california
It usually just shoots really high.
If I floor it in an instance its around the whole presure gauge past 30.
Only when I let off the throttle it will stop building pressure
 

Barnes

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Hmmm, I'm not totally convinced it is boost creep. I think you should try the procedures I suggest.
 

thedsmguy

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Mar 20, 2009
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Vancouver Washington
and NO NO NO NO NO the computer will not "save you" by fuel cutting. You will damage a lot of stuff just willy nilly running around on 30lbs of boost, or even 20 (possibly).
 

yeti

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Oct 13, 2010
Messages
803
Location
san diego california
The computer should save you.....

Anyways I took out wga and the pin kinda got destroyed since it was so rusty the wga ops at 15 psi of pressure with it out of the car
I cannor drive the car now as we are working on the camaro behind it..

Where could I purchase a stronger internal wga
And how expensive/how much work are the external ones
 
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