Yet another 5.2 355 bypass valve question | FerrariChat
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Yet another 5.2 355 bypass valve question

Discussion in '348/355' started by markcF355, Jun 21, 2005.

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  1. markcF355

    markcF355 F1 Rookie

    Jun 6, 2004
    3,493
    Schmeckelstan
    Full Name:
    Mark
    #1 markcF355, Jun 21, 2005
    O.K., I know it’s been beaten to death but I just have to ask. Has anyone had any long term problems related to forcing the bypass valve open on a 5.2 355? I moved the vacuum hoses around so mine would stay open but I chickened out after the check engine light came on and put it back to normal. I reset the light but I really miss the way it ran and sounded with the valve open. I believe the third temperature sensor was responsible for the light turning on. As long as the ECU will run in closed loop mode with some of the exhaust flowing through the secondary cats, I’ll spoof the temp sensor. Now all that being said, has anyone had any problems related to running with an open valve on a long term basis?
     
  2. MufflerMan

    MufflerMan Formula 3

    Jun 12, 2005
    1,564
    Sacramento Ca
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    Colby Sandman
    #2 MufflerMan, Jun 21, 2005
    I had a 96 Spider about 4 years ago and I actually wired the vave in the open position. My car had a tubi on it and it sounded much better that way. I drove it that way for 7000 miles without a problem, and curiously no check engine light. My current car is a 95 355B with a Tubi and Tubi test pipes, so I don't need to do anything with my valve this time around. If you can trick your light to stay out, it would seem to me it not only makes your car sound better, but maybe prolong header life?(less heat)
     
  3. markcF355

    markcF355 F1 Rookie

    Jun 6, 2004
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    #3 markcF355, Jun 22, 2005
    I don't think the 96' had the third temperature sensor, so no light? Also, anybody know how to tell if the 5.2 ECU is in open loop?
     
  4. tonyyoshi

    tonyyoshi Formula Junior

    Jan 8, 2005
    308
    Hong Kong
    Full Name:
    Tony Brooker
    #4 tonyyoshi, Jun 23, 2005
    I wired mine open on my 97 355 with Tubi and had no check light show up. Maybe the check light on your car was related to messing with the vaccuum pipes instead? Why don't you just wire it open? Anyway, I had zero problems. Car was lovely and loud. Now I have a Capristo and Hyperflow cats so I'm afraid to wire it open if it's TOO loud. Neighbours hate it as it is now...
     

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