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Car has no O2 sensor! Can I..?

Discussion in 'ECU's, Electronics, and Tuning' started by poch333, Sep 9, 2006.

  1. poch333

    poch333 New Member

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    Hello,

    My 95 Civic ESi (Philippine domestic version) is similar to the U.S. EX version, I think. It has a PH16 engine (PGM-FI, 16Valve, 1.6Li, SOHC non-vtec, ECU code P27) but it has no oxygen sensor! This is common knowledge here, and there is a plug where the sensor should be. My question is, is this a great disadvantage in terms of mileage? Average mileage for civics here is 18 to 24 MPG (~8-10km/liter).

    Why did Honda do this? Is the ECU always running in open loop mode? Can we somehow buy an O2 sensor and put it in, and if so, will this buy us much MPG-wise?

    Thanks so much in advance, I hope someone can help.
     
  2. TurboMirage

    TurboMirage YEEAAAHHH VIP

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    can you provide pictures? this is interesting :)

    the US EX version is a 16v 1.6L sohc vtec.
     
  3. poch333

    poch333 New Member

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    Thanks for the reply. The first photo is of the spot where the service manual says the O2 sensor should be (the arrow points to the metal plug). The second is a top view of the whole engine (sorry the engine's a bit dirty). I also posted photos of the motor and chassis numbers.

    Could there be another oxygen sensor hiding somewhere?
    I consulted the Civic EG series (92-95) manual, and all other parts are an almost perfect match for the 4-door coupe with D16Z6 engine, except it's non-vtec. The manual doesn't say anything about another sensor.

    Again the ECU is a P27, which, according to the reference section, is for a JDM 1.6L SOHC vtec. It would seem that Honda disabled the VTEC for this model (ESi, Philippines) but used a JDM ECU, which presumably has the capability to handle VTEC and an O2 sensor. If it didn't, then it would have a different ECU code right (is this correct)? As for the engine, it does have a different code: PH16.

    Any ideas on why Honda did this? :confused: I think the emission laws here were not as stringent back in '95, and even today they still aren't as strict as in the U.S.

    Thanks again! I would really appreciate any help. I can post more photos if you think it would help.
     

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  4. TurboMirage

    TurboMirage YEEAAAHHH VIP

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    wow! interesting.

    try following the ehxuast back from the header to see if there is an o2 sensor there :)
     
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