Help me Diagnose my Cobb Stage 2 Low Boost Problem
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This is a discussion on Help me Diagnose my Cobb Stage 2 Low Boost Problem within the Tuning: Electronic Engine Management forums, part of the Tech & Modifying & General Repairs category; Background.. 2002 Wagon, Catless belmouth downpipe, catless up-pipe, HKS exhaust and Cobb Accessport flashed at stage 2. <600 ft elevation. ...

  1. #1
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    Help me Diagnose my Cobb Stage 2 Low Boost Problem

    Background..
    2002 Wagon, Catless belmouth downpipe, catless up-pipe, HKS exhaust and Cobb Accessport flashed at stage 2. <600 ft elevation.

    I have been at stage 2 for 15 months and have never been able to hit target boost.

    things I have tried,

    - various base and real time maps including HWG which I am running now
    - adjusting the wastegate arm.
    -going back to stock.
    -monitoring boost with both aftermarket boost gauge and the Accessport

    I hit about 14.5 psi in 4th and 5th, the wastegate arm adjustment allowed me to hit higher but the ecu would keep 'bouncing' the boost back down to below 15...let me explain, it would boost say 16 or 16.5 psi under load and it seemed like the ecu would step in and limit the boost back down...spike back up, then back down etc.

    I have contacted Cobb and exchanged emails with Jason. He seems to think it is a mehanical issue. I can't see how, the car can build boost beyond 15 psi but the ecu doesn't seem to want to let it. I never had a issue with it not making full boost in it's stock form and actually reverted back to stock (minus the up-pipe and hks exhaust) for my emissions test last month and was still making 13 psi.

    Any input woould be much appreciated.

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  3. #2
    Registered User uncle lewie wrx's Avatar
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    Did you check your up/down pipes or any other components (exhaust or other engine based area) for leaks???
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    Registered User Wrinkleboi's Avatar
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    do you still have all of the factory hoses for all of your boost control components? turbo - wastegate actuator - factory boost controller, including the restrictor pill and the 1/4 restrictor before the fbc? if you've touched any of that at any point, it might be something to look into. or maybe check for cracked hoses or just replace all of them, making sure to keep all of the plastic resistors/connectors in place where they should be.
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    Try a different gas station, go for 94 octane if you are using 91. I find a noticable difference using Chevron 94. After checking all of the things wrinkleboi mentioned.
    Last edited by wrxdrvr; 12-19-2005 at 12:12 PM.
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  6. #5
    Registered User rallymaniac's Avatar
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    stage 2 is not supposed to go over 16PSI. Even Cobb states that most boost for that map is 15.8. So by boosting more, you have something wrong with your car (wrong wastegate lenght, etc.). i'm in chicago area and have stock 3rd cat with my Bosal DP and catless UP and i don't hit more than 15PSI in 3rd 4th and sometimes 15.5 in 5th. I don't feel like screwing around with that and i'm happy with my boost.
    If you've had your map for more than 1000miles and you're not hitting higher than 15PSI, that means you won't. How many turns did you adjust your wastegate arm by?
    Try turning it less if you really want higher boost.
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    Moderator timber's Avatar
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    Quote Originally Posted by uncle lewie wrx
    Did you check your up/down pipes or any other components (exhaust or other engine based area) for leaks???
    especially at the up-pipe..
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    Registered User uncle lewie wrx's Avatar
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    Quote Originally Posted by timber
    especially at the up-pipe..
    Yes that thing is a biznotch. Plus he said he swapped out his exhaust for emissions then re-applied them.
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    Moderator   Sasquatch's Avatar
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    I see 1.1 bar (just under 16 psi) in 4th or 5th in cooler weather only. In the summer? Forget about it. Did not see it listed - are you at the latest revision (1.30)?
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    Registered User dcpatters's Avatar
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    This sounds similar to the 3/16 mod. I tried it for laughs and noted similar results, peak boost, then it would fall off. Would not hurt to check.
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    Registered User Parker-gc8's Avatar
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    *** Wondering where the thread starter is..***

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    Sorry for the late reply...working

    Up-pipe and downpipe are not leaking, all hoses are factory (never had a MBC or tried 3/16th mod)..latest revision of Cobb's stage 2 hwg map.

    I tried adjusting the wastegate arm again and now I will get 15 psi but nothing higher.

  13. #12
    Registered User Parker-gc8's Avatar
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    I'd put the normal map on, adjusting the wastegate with that map makes it hard to reference your boost levels to our cars.

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    Quote Originally Posted by Parker-gc8
    I'd put the normal map on, adjusting the wastegate with that map makes it hard to reference your boost levels to our cars.
    I will give that a try.

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    My mods:
    Erz UP pipe
    Erz Down Pipe
    Erz Turbo back exhaust
    K&N drop in
    air silencer removed
    3/16" mod

    and i hit between 1bar and 1.1bar...

    no engine management....

    i think its a bit rich...

  16. #15
    Registered User Parker-gc8's Avatar
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    I thought ERZ had a divorced wastegate downpipe?

    So, How many turns which direction are you from the stock wastgate actuater arm adjustment?

    With the HWG combo you have been running have you ever seen boost fluctuate alot?

    When you were hitting 16.5 the ECU backed you back down to 15 because you were running above target boost. Somthing tells me you just jumped over your ideal running condition for cobb's maps.

    If you have the 3/16th's mod that is the first thing you should put back to stock. You'll never hit target boost with that fighting the ap's map.

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