New to subarus! now i need some help!
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This is a discussion on New to subarus! now i need some help! within the General Maintenance, Troubleshooting & Accidents. forums, part of the Tech & Modifying & General Repairs category; hello, first off let me say that i know a pretty good amount about cars, turbos, engines and such... however ...

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    New to subarus! now i need some help!

    hello,

    first off let me say that i know a pretty good amount about cars, turbos, engines and such... however as most of you know- subarus are alittle bit different animals then the rest haha.

    last month a friend of mine purchased an 03 sonic yellow wrx sedan. its in pretty good shape and only has 65k miles on it
    heres the issue:
    the car has some modifications done to it and it seems like the more i get into it, the more i find. heres a list of what iv found so far:

    larger turbo- looks to be vf39 from an sti but im not sure
    3" down pipe
    borla catback
    samco sport intake pipe and hoses
    perrin boost control soliniod
    turbo xs utec engine managment
    lots of suspension mods as well.

    my friend wants the car to be much closer to stock and to be very reliable. my thought is to let the factory ecu handle the tune and leave some of the aftermarket parts on, as this would make it more reliable i would think. so i have plugged the factory ecu back in and put the stock boost control soliniod back on and reran and routed all the hoses back to factory. the cars idles and runs fine until you load it up enough and get into boost- heres where i have the issue...

    the car misfires or shudders until you let your foot off.
    it seems to be the worst in lower gears and happens at about 4k rpm but as i said it depends on the load and higher boost levels.
    the check engine light does not come on.
    i disconnected the battery all night to reset the ecu and still get the same issue

    i guess my questions is does anyone know what i should check or replace next? is this a fairly common problem or not? i dont really have the money to take it somewhere and given the mods on the car, im guessing alot of shops wouldnt touch it anyway.
    any help would be greatly appriciated

    thank you

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    Master Baiter EJ257's Avatar
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    It would require upgraded injectors to run that turbo; the way the ECU is setup (likely stock), you're probably dumping an overly excessive amount of fuel into the cylinders. That car should not be driven without the UTEC on it, with the proper map selected.
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    thank you,
    That does make sense. iv used slightly bigger turbos on other cars... my mr2 and turbo celica mostly but they ran great on the factory ecu thats why i was confused.

    so for reliableity- would i be better off going back to the stock turbo and stock ecu??? the original tune with the utec was fine but it never idled smooth and or seemed to run quite right so id prefur to get rid of it...

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    Registered User Heide264's Avatar
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    Quote Originally Posted by Wrexy View Post
    so for reliableity- would i be better off going back to the stock turbo and stock ecu??? the original tune with the utec was fine but it never idled smooth and or seemed to run quite right so id prefur to get rid of it...
    If you are concerned about reliability, the only after market part you should concern yourself is a de-catted up pipe.

    Otherwise, any aftermarket part on these cars generally requires a tune - both for reliability and any power gain. The older models do tend to be more lenient towards having a down pipe without a tune. However, if reliability is your primary concern, get all of the other stuff off.
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    Master Baiter EJ257's Avatar
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    Re: New to subarus! now i need some help!

    Quote Originally Posted by Wrexy
    so for reliableity- would i be better off going back to the stock turbo and stock ecu??? the original tune with the utec was fine but it never idled smooth and or seemed to run quite right so id prefur to get rid of it...
    The safest option is to return the motor to stock, with the exception of the catback and uppipe, and to be sure that a stock map is on the car.

    To reiterate what I said before, that car should not be driven in its current state.
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    Ok that pretty well answers my question

    guess ill have to look into the cost of these stock parts and make the decision.

    thank you for your help!

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    Pro Manscaper Mikie13's Avatar
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    Or, if it was actually built right and does have all the supporting options to correctly run a VF39 (which it could be with the UTec), why not just leave it? STIs run perfectly reliably with a VF39...seems like a waste of money and time to me...

    ...unless of course you know the mods are all hack-job mods.
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    Registered User Ingo's Avatar
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    Got some money and a laptop? If so, get the Taxtrix adapter and download romraider (free). Log the car and see if you can find out what's wrong. Maybe even get a tune for the setup into the original ECU and remove the Utec. Adapter is about $180. A tune (like Torqued Performance, but Eric only does 3rd gen, or so I understand) should be possible for probably less than $200. Just something to think about.
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