My car bogs over 10psi

S

STInate

Baxley’s Speed Shop
After I replaced my o2 sensor with a used one the other day everything seemed to work fine for a little while about half an hour of hard driving. Then I went to go into full boost and it started bogging down over 10psi. I thought it was an intercooler leak but I have checked and double checked all the couplers. I even replaced one of them. Its also having a hard time idling now too. It seems to drive ok as long as you dont go past 10 psi and not when your idling or taking off. Any ideas?

 
I've heard of the plastic sides of the intercooler cracking- can be hard to see but under boost just blows out. If you have an AP datalog and then view whats happening through a spreadsheet.

 
couldn't be a turbo eh? Hard to diag this stuff over the intertubes

 
The turbo was rebuilt less then 1000 miles ago but I suppose anything is possible with my luck. I have a front mount intercooler which is metal so I doubt that is leaking.

 
I thought about ordering some but figured they were probally ok since they only have 3000 miles on them.

 
with the mix your running and tune plugs could go pretty easy and its a cheap part to start with.have you even pulled one out yet and looked at them take you all of 10 minutes to do
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-----Added 8/23/2009 at 09:17:57-----

you have to remember you are not running a stock sti anymore where the plugs will last 50k miles your running a highly modified sti which part life is shortened greatly
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The turbo was rebuilt less then 1000 miles ago but I suppose anything is possible with my luck. I have a front mount intercooler which is metal so I doubt that is leaking.
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haha i was just pulling your chain
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i hope it's not the turbo. something simple like plugs or a leak would be sweet

 
I took it out this morning without the o2 sensor plugged in and it was bogging really bad when you try to take off from a stop. Once again when you get going its fine until about 10psi. It almost wouldnt even move.

 
You gotta datalog to narrow this down, I'm no pro by any means but I'm wondering what your DAM readings are, or if it is or thinks it is picking up knock. I wonder because it sounds like its going straight to waste gate boost. If you can datalog and its picking up knock, your waste gate duty cycle will be 0% and DAM readings will be below .35

-----Added 8/24/2009 at 04:56:59-----

Maybe a problem with the Boost Control Solenoid OR Wastegate Actuator?

 
High MAF readings indicate a boosted (post turbo) leak, and low MAF readings indicate a pre turbo or intake leak- this should point ya in the right direction...

 
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