elantra 2001 has no oxygen sensor and it ECU runs in open loopalways!

Discussion in 'Hyundai Elantra / Lantra' started by CMOS, Dec 9, 2009.

  1. CMOS

    CMOS Guest

    Hi all,
    I recently bought an Elantra 2001 model car. When i did the emmission
    test, it failed with high CO and HC. CO percentage was in range 5-6.
    Its fuel consumption is also very high.

    The idle is very smooth, no knocking when accelerating and no other
    unusual behavior either.

    As the first thing, i replaced all spark plugs, got the distributor
    checked and wires checked. They are all fine. Then i did a fuel system
    clean and checked whether there are any problems with injectors and
    they were fine too.

    Today, i got its ECU scanned and it gave the code p0342. I replaced
    the camshaft position sensor, but it still gives the same code. In
    addition, the reading of oxygen sensor voltage is 0.0V always. When
    inspected, we could not find any oxygen sensor! And the engine runs
    always in open loop (even after it gets heated!). Now im fully
    confused! Please let me know whether there are engines where you don't
    have a oxygen sensor? And if there are engines like that, will they
    run in open loop always?

    thanks in advance!
    CMOS, Dec 9, 2009
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  2. CMOS

    hyundaitech Guest

    You'll find the front oxygen sensor in the exhaust manifold-- it
    screws into the transmission side of the manifold. The rear oxygen
    sensor is in the front exhaust pipe. If you actually had no oxygen
    sensor, you'd have trouble codes indicating an open heater circuit for
    each sensor. I'll note, however, that since closed loop by definition
    uses front oxygen sensor values to determine how much fuel to deliver,
    lack of oxygen sensors would mean the vehicle would always operate in
    open loop.

    With the recurring P0342, you should check the camshaft timing. It's
    possible that it's one tooth off. This would cause the emission
    failure and the odd oxygen sensor readings.
    hyundaitech, Dec 14, 2009
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  3. CMOS

    CMOS Guest

    Thanks for the valuable advice, i will check for timing.
    BTW, i got the shop manual for the car and according to it, this car
    was made for leaded petrol and has no oxygen sensors or catalytic
    converters. As you have mentioned, this should run in open loop
    always, i believe.
    And one more help, Would a wear and tear of petrol injectors increase
    the CO emission to 4%. The mileage of the car is 167000 KM.

    CMOS, Dec 16, 2009
  4. CMOS

    hyundaitech Guest

    Suppose I shouldn't have assumed. This car isn't in the U.S., is

    An injector issue would typically cause the car to run poorly, so that
    isn't likely the issue. Stick with sorting out the reason for the cam
    sensor code. Fixing that will likely fix the emissions.
    hyundaitech, Dec 18, 2009
  5. CMOS

    CMOS Guest

    thanks. the car was made for Sri Lanka.
    Is there a place where i can but the correct manual for this car by
    giving the VIN? i checked the local agent and they say they dont sell
    it to customers. (so that they can have the service monopoly !)
    CMOS, Dec 19, 2009
  6. CMOS

    hyundaitech Guest

    I'm not knowledgeable enough about non-US cars to know where that
    would be. You can register for an account at www.hmaservice.com, but
    it includes information only for U.S. models. At this point, I don't
    know if your engine is the same as one of those available in the U.S.
    hyundaitech, Dec 20, 2009
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