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Thread: F355 check engine light

  1. #1
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    Default F355 check engine light

    First one of the season...
    Car runs great, per the owner.
    What shall we find?

    P1126
    P1124

    Fuel trim, which point to some sort of a lean condition

    And then there's the shorted O2 heater code for dessert.
    Last edited by Radioman; 04-18-2015 at 12:31 PM.
    Sarasota Italian Garage, LLC
    "The Fluent in Ferrari Guys" celebrating 37 years of service excellence
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  2. #2
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    Smoke testing of the exhaust system reveals a substantial leak before the catalytic converter on the 1-4 bank, at the junction for the exhaust crossover. Although not the cleanest diagnosis, if we are getting false air into the cat, the O2 will sense a lean condition and adjust accordingly. Analysis of real time traces for the O2 sensors support this theory. Meanwhile, I'll be testing the intake tract for vacuum leaks and then verify fuel pressure.
    Sarasota Italian Garage, LLC
    "The Fluent in Ferrari Guys" celebrating 37 years of service excellence
    Lakewood Ranch, FL
    www.fluentinferrari.com

  3. #3
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    Further evap testing reveals:
    Smoke leaking at the MAF to intake bellows junction.
    Smoke leaking at 5-8 bellows to air box junction.
    (Both of these junctions are sealed with an o-ring.)

    -More sources for false (non-measured) intake air, supporting lean conditions.
    Sarasota Italian Garage, LLC
    "The Fluent in Ferrari Guys" celebrating 37 years of service excellence
    Lakewood Ranch, FL
    www.fluentinferrari.com

  4. #4
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    All fixed and down the road...
    Replaced both donuts gaskets for bypass pipe-No more leaks faking out the O2 sensors
    Replaced the hardware at the bypass valve-Exhaust leak repaired
    Replace three o-rings in the intake tract ducting-No more false air sneaking around the MAF

    New O2 sensors fixed the heater circuit short

    Drives great!
    Sarasota Italian Garage, LLC
    "The Fluent in Ferrari Guys" celebrating 37 years of service excellence
    Lakewood Ranch, FL
    www.fluentinferrari.com

  5. #5
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    Another fine repair!
    History always repeats itself,... that's one of the things that's wrong with history.

  6. #6
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    Quote Originally Posted by Caveman View Post
    Another fine repair!
    Thank you, but perhaps better stated 'another F355 mystery resolved.'
    Sarasota Italian Garage, LLC
    "The Fluent in Ferrari Guys" celebrating 37 years of service excellence
    Lakewood Ranch, FL
    www.fluentinferrari.com

  7. #7
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    I gotta hook that smoke machine to my E39.
    Birdman308 for parts and tutorials!

  8. #8
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    Quote Originally Posted by Birdman View Post
    I gotta hook that smoke machine to my E39.
    I'll check to see if I have any BMW smoke oil. If not, we'll just make some up.
    Sarasota Italian Garage, LLC
    "The Fluent in Ferrari Guys" celebrating 37 years of service excellence
    Lakewood Ranch, FL
    www.fluentinferrari.com

  9. #9
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    Quote Originally Posted by Radioman View Post
    I'll check to see if I have any BMW smoke oil. If not, we'll just make some up.

    Is that more or less reliable than the Ferrari smoke?
    Birdman308 for parts and tutorials!

  10. #10
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    A bit less finicky!
    Sarasota Italian Garage, LLC
    "The Fluent in Ferrari Guys" celebrating 37 years of service excellence
    Lakewood Ranch, FL
    www.fluentinferrari.com

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