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Old 02-01-2005, 10:41 PM   #1
gotmilk2001
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Impreza WRX STi i got a problem with my 04 sti can anyone help?

i have an 04 sti with a full turboxs exhaust with down pipe and a aem cold air intake.When im excellerating hard 4,5,6 the car falls on its face and throws check engine light with the cruise light blinking!!The light goes off after awhile but comes back on every time im pushing the car al ittle?Does anyone know whats happening and how to fix?Any help would be great!





thanks
trevor
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Old 02-01-2005, 10:47 PM   #2
Skeete
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Old 02-01-2005, 10:47 PM   #3
seattle944t
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A little search on 'boost creep' and or 'fuel cut' will give you all you want to know and more - short answer is that you have uncontrolled boost and the ECU is shutting off the fuel to protect the engine.
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Old 02-01-2005, 10:50 PM   #4
gotmilk2001
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how should i fix this?
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Old 02-01-2005, 10:51 PM   #5
Skeete
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engine management ie, cobb AP, utec, or port the waste gate. searching will give you a better answer.
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Old 02-01-2005, 10:56 PM   #6
gotmilk2001
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my AM boost gauge reads 21pds at alittle over 5000rpm. everyone ive talked to says boost cut is 18pds. so my gauge must be wrong. am i damaging any thing now?
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Old 02-01-2005, 10:59 PM   #7
Skeete
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pds? you mean psi? both are to high for stock em, prolonged overboosting will hurt your engine/turbo.

Last edited by Skeete; 02-01-2005 at 11:11 PM.
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Old 02-01-2005, 11:17 PM   #8
2phless
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Fuel cut is set for some given PSI (might be 18) but it is delayed (timewise) to allow for spike circumstances. In that delay you may reach 20+ psi and think that is the cutoff.

Others here are experimenting with different wastegate restrictor diameters to allieviate the issue. A restrictor with a larger hole in it might fix the problem.

Again, spend some time with searches here and research similar problems. I don't know all the specifics off hand. I fixed my creep myself by porting. I think there are less drastic manners to resolve the issue though. My turbo was creeping with aftermarket EBCs and the restrictor pill was no longer in the plumbing, so porting seemed the only way to beat it... but all the solutions seem to change from car to car.

Some EM systems can fix it by throwing more fuel at specific loads to cool EGTs and reduce pressure. That can work but it's a loss in HP (sometimes) according to some.... like we've said. Lots of reading...

Gaining power in an STi tends to be an avalanche. Once you start you can't stop, even if you want to. You set a mild goal and the standard WRX upgrades push you past where you want to be. It'll get expensive in a hurry. EM is almost a given. And then turbo and fuel upgrades get just too tempting.

Second Mortage your house and ride the wave baby! It'll be worth it in the end.

Or you'll lose your house...
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Old 02-01-2005, 11:41 PM   #9
gotmilk2001
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Thanks for the input im just going to have to buy a utec! After reading it seems to be a real common problem. Cant you just buy a new wastegate instead of porting the stock one? A local speed shop says they can install A $50 sensor that will cure the code problem is that just a wrong diagnosis?
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Old 02-01-2005, 11:58 PM   #10
burnin4
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a utec will help. I have an 04 STi with txs catless tbe, txs intake, and a utec (has not been custom tuned) and I've hit boost creep/fuel cut once, (while racing a 355gts on the highway). It hasn't been a big problem for me and I give my car hell . I'm not sure if the utec will "fix" boost creep, but I think tuning can help cut it down.
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Old 02-02-2005, 08:40 AM   #11
1/500yellowwrx
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I have the same setup as burnin4, but my utec is tuned and I never have boost creep. I am pushing 20psi. Sometimes I wish I had it that way I would not have to watch my psi drop from 20 to 16 will running through the gears.
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Old 02-02-2005, 10:33 AM   #12
polyol
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Have it scanned find out exactly what it is...have you done the mechanical mod yet?

http://forums.nasioc.com/forums/show....php?t=681693]

Sounds like boost creep/spike. I spike up to 19/20psi but it comes down quickly to 17psi w/ my 3" cattless TBE. I have some sort of EM though...so no cel for me. Read this entire thread. If you have no experience with cars...let a professional port the wastegate.

http://forums.nasioc.com/forums/show...port+turbo+sti
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