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hypreflows and low cat efficiency codes

Discussion in '348/355' started by emac, Apr 14, 2019 at 2:21 PM.

  1. emac

    emac Formula Junior
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    Sep 14, 2014
    575
    upstate SC
    Full Name:
    ernest
    1996 spider 6spd with Tubi headers, hyperflow cats and stock exhaust. All new o2 sensors. I have had this setup for a while, but I honestly haven't driven many miles and very few (if any) trips over 30 miles. Yesterday I went about 60 miles on the interstate (in pouring rain) very easy driving. When I pulled off the interstate and slowed the CEL came on. Pretty sure I recall a pending code years ago when I first put these on, so I guess it finally upgraded to a CEL. The code is both banks, low cat efficiency.

    Did some reading last night and this seems to be a common issue. A read about a few fixes:
    1. reset CEL and dont worry about it
    2. Post cat o2 extenders
    3. add ground wire from o2 sensor body to a ground
    4. OEM cats

    OEM cats are out for now. I dont mind resetting, but would like a work around. Anyone have any experience or thoughts on the ground wire or 02 extenders.

    Other than the pouring rain, CEL, flat spotted front tires, and no A/C the car ran great! These things punish you when you let them sit!!

    FWIW, the clutch pedal had a tiny "bump" right at the top of the release. It was very smooth except the very last bit. I had just flush the fluids, and didnt see any leaks. I gently eased back the master boot and squirted a tiny bit of lube on the shaft. Fixed it.

    Thanks guys.
     
  2. kenneyd

    kenneyd Formula Junior
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    Sep 30, 2014
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    NE FL
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    Ken
    I have stock headers, hyperflows, and capristo and have never had that code.
    Im just thinking out loud, the lack of prior driving, plus cool rain, and then the added fact of you babying it because of the rain... the cats may have never heated up enough to work.
    Reset the code, take it for a drive and just beat on it a little. that will clean out the cats of any soot and I bet the code wont come back.
     
  3. yelcab

    yelcab F1 Veteran
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    Nov 29, 2001
    8,775
    San Carlos, CA
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    Mitchell Le
    These will do it:

    Extender on rear O2 sensors, and ground wires to the rear O2 sensors.
     
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  4. emac

    emac Formula Junior
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    Sep 14, 2014
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    upstate SC
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    ernest
    I was kind of thinking that until I read about others having an issue. I had the wife in the car, so I really never got to open things up like I normally do. If extenders and a ground wire will work, that would be nice.



    Anyone have a link to the extenders? I read about getting some angled ones for clearance. The link I found on an old thread was dead.

    Found these: https://shop.redline360.com/collections/all/megan-racing-check-engine-light-eliminator
     
  5. drbob101

    drbob101 F1 Rookie
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    Nov 26, 2012
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    #5 drbob101, Apr 14, 2019 at 6:33 PM
    Last edited: Apr 14, 2019 at 6:38 PM
    Sorry Earnest just saw your post and emails.

    I’m not sure the ground wire did it for me or the extenders or both. I would go ahead and do both and see what happens.

    I’ll find the link for the ones I used but I know fabspeed has some and others as well

    http://www.bigdaddiesgarage.com/

    This is what I have. They are minicats not just tubular extenders. Have small catalytic converters in them
     
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  6. emac

    emac Formula Junior
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    ernest
  7. drbob101

    drbob101 F1 Rookie
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    Nov 26, 2012
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    Earnest I don’t cat cat efficiency codes now. Of course that may change but I haven’t had them since installing big daddies a few years ago
     
  8. emac

    emac Formula Junior
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    Sep 14, 2014
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    ernest
    Are you using the Big daddie O2 mini cat? Any fitment issue with them being straight? Thanks.
     
  9. Skippr1999

    Skippr1999 Formula 3
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    Biggdaddies are cheap and worked for me. Tubi headers & test pipes.

    I hadn’t heard about the ground wire technique. That’s interesting.
     
  10. drbob101

    drbob101 F1 Rookie
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    Nov 26, 2012
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    Bob Ferraris
    Yes I am anno issues with hyper flows
     
  11. emac

    emac Formula Junior
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    Sep 14, 2014
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    ernest
    Thanks guys, I am going to order some Big Daddies and give them a try.
     
  12. SoCal1

    SoCal1 F1 Veteran
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    Jun 14, 2011
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    Tim Dee
    You just may have slow responding O2 sensors, check them per standard tests
     
  13. Qavion

    Qavion Formula 3

    Feb 20, 2015
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    Ian Riddell
    Thanks for the tip!
     
  14. Challenge

    Challenge Formula 3

    Sep 27, 2002
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    1999 5.2 with OEM headers, Hyperflow cats and Tubi exhaust. I resolved these cat inefficiency codes with the L-shaped extenders. Installation is a bit tight. I wanted mine angled up on both banks so any condensation would run down away from the O2 sensors.
     
  15. ernie

    ernie Two Time F1 World Champ
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    Nov 19, 2001
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    Those are a bargain!!! Thanks for sharing!
     
  16. Skippr1999

    Skippr1999 Formula 3
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    It’s amazing the cost reduction when the product isn’t specifically targeted to Ferrari owners.
     
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  17. taz355

    taz355 F1 Rookie
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    Feb 18, 2008
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    Grant
    I was same as Dr Bob
    Minicat extenders post and no need for ground wires curred it 10 plus years ago
     
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  18. 05elise

    05elise Rookie

    Jul 20, 2011
    5
    Sharpsburg, GA
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    Dan
    I had plain extenders on the rear O2 sensors with my Hyperflows and they worked just fine with no CEL but it became a problem when I had to have the car pass an emissions inspection to register the car. The reason there was no CEL was due to the inability of the OBD II system to ever ready enough I/M monitors because of the extenders. Due to the not ready state of the onboard diagnostics the emissions test station could not interrogate the OBD II system so the car failed the inspection.

    My only option was to remove the extenders to allow the monitors to get to a ready state and then the low catalyst efficiency codes set and the CEL came on. Of course now that I had a CEL the car would not pass an emissions inspection retest so I had to do something with the cats. I ended up having to remove the Hyperflows and install some aftermarket EPA certified cats with the O2 sensors installed normally without extenders. With only one drive cycle enough I/M monitors were set for the OBD to start reporting and no CEL came on so it was back to the emissions test station to have the car pass with no problems. After passing the retest I swapped the Hyperflows with O2 sensor extenders back in and put the EPA certified cats in storage until the next time my car needs an emissions inspection.

    The only reason I brought all this up was just to warn anyone that is required to pass an emissions inspection that the car will not pass with Hyperflows and O2 sensor extenders installed. You might be able to get by with the mini-cat extenders but you would have to see if they allow the I/M monitors to ready before taking the car for testing and if the test station does a visual inspection (which mine does) of your emissions equipment they will fail you when they see the extenders.
     
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  19. WATSON

    WATSON F1 Veteran
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    Sep 9, 2010
    8,190
    WI
    Was getting the same CEL on my car with heyperflows.
    Eight years ago (15,000 miles) I put these extenders in and have not seen the CEL again.
    I do get a pending code from time to time....but overall very happy. YMMV
     
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  20. Subarubrat

    Subarubrat Formula 3
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    Apr 1, 2009
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    Scott
    I can't help but think they changed suppliers on the core material or something, I have had hyperflows with normally installed 02s and never a light or problem. I know our cars can vary some, but it seems the cats have very different behaviors.
     

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