Results 1 to 8 of 8

Thread: What oxygen sensors should I use???

  1. #1
    Join Date
    Mar 2018
    Location
    Washington DC
    Posts
    30
    My Cars
    2002 BMW 325xi

    Lightbulb What oxygen sensors should I use???

    Check Engine light came on and the codes said P0171 P0174
    System running to lean bank one and bank to
    does this mean i have to replace the oxygen sensors?
    I changed the coils and spark plugs because it said it was
    misfiring.

  2. #2
    Join Date
    Mar 2016
    Location
    Portland, OR
    Posts
    712
    My Cars
    2002 325Ci Cabriolet
    Quote Originally Posted by DBLuke View Post
    Check Engine light came on and the codes said P0171 P0174
    System running to lean bank one and bank to
    does this mean i have to replace the oxygen sensors?
    I changed the coils and spark plugs because it said it was
    misfiring.
    You likely have a vacuum leak. These two codes are the most common codes your car will throw. The likelihood of your 02 Sensors being bad is almost equal to your odds of winning a 10-spot Keno. Your next step is to perform a smoke test to check for leaks.

    FWIW - the only 02 Sensors that should ever be used on a BMW are Bosch.
    Last edited by All2kool; 03-27-2018 at 07:40 PM.

  3. #3
    Join Date
    Dec 2013
    Location
    Chicagoland area
    Posts
    4,372
    My Cars
    EXOTICS
    It definitely should not automatically mean that.
    Lean codes on both banks generally indicates an intake leak.

    IF you are mechanically inclined, and a DIYer,
    first remove rubber intake boots, then squeeze them and all associated hoses,to expose hard to locate cracks,
    which cause unmetered air intrusion-leading to lean fuel mixtures.Thus causing misfires and lean fuel mixture codes.
    Replace items where cracks are found.
    IF not,
    then I suggest a smoke test performed at a reputable BMW shop with a pro smoke machine.
    Last edited by MIKYZZ4; 03-27-2018 at 07:50 PM.

  4. #4
    Join Date
    Mar 2015
    Location
    west chicago il
    Posts
    509
    My Cars
    01 E46 330i 5sp man spor
    Use bosch o2 sensors. As mentioned above p0171/174 are most likely caused by a vacuum leak or other unmetered air leak like a broken intake boot. It is recommended to replace o2 sensors after 100k. You can just replace the upstream sensors because those are the two that control fuel mixture. This will not likely resolve the issue. You need to do/get a smoke test.

    Sent from my SAMSUNG-SM-G870A using Tapatalk

  5. #5
    Join Date
    Mar 2016
    Location
    Portland, OR
    Posts
    712
    My Cars
    2002 325Ci Cabriolet
    Quote Originally Posted by randy72877 View Post
    ...p0171/174 are most likely caused by a vacuum leak or other unmetered air leak like a broken intake boot.
    A DISA that does not have vacuum can also cause a lean code. I know, my DISA failed a vacuum check and after it was replaced, I've not seen another lean code. That was more than 1,100 miles ago.

  6. #6
    Join Date
    Mar 2015
    Location
    west chicago il
    Posts
    509
    My Cars
    01 E46 330i 5sp man spor
    Quote Originally Posted by All2kool View Post
    A DISA that does not have vacuum can also cause a lean code. I know, my DISA failed a vacuum check and after it was replaced, I've not seen another lean code. That was more than 1,100 miles ago.
    Your disa probably was leaking where it seals into the intake. Mine did that and I fixed it with an o ring. Found it with a smoke machine. The hardest part is removing the original seal.

    Sent from my SAMSUNG-SM-G870A using Tapatalk

  7. #7
    Join Date
    Jul 2011
    Location
    Arlington, VA
    Posts
    9,933
    My Cars
    2018 BMW M240i
    Yeah, the DISA o-ring is, in fact, no an o-ring in this traditional sense. It’s actually molded into the DISA. Yes, it takes some time to fully remove the “o-ring.” I’d replace it (if the DISA is good) with an o-ring from German Auto Solutions.

  8. #8
    Join Date
    Mar 2016
    Location
    Portland, OR
    Posts
    712
    My Cars
    2002 325Ci Cabriolet
    Quote Originally Posted by randy72877 View Post
    Your disa probably was leaking where it seals into the intake.
    NO, it failed a vacuum check, just as I said.

Similar Threads

  1. ordered ACS sport susp. - what alignment number should I use?
    By Chuck in forum 2001 - 2006 M3 (E46)
    Replies: 2
    Last Post: 08-17-2003, 12:14 PM
  2. What size tire should I use for 18x8.5 wheels?
    By samm3 in forum 1992 - 1999 M3 (E36)
    Replies: 4
    Last Post: 05-22-2003, 09:34 PM
  3. Oxygen sensors... what oxygen sensors?!
    By ACS320i in forum 1991 - 1999 (E36)
    Replies: 7
    Last Post: 03-24-2003, 03:55 PM
  4. What license plate should I use on my car?
    By Pepe240sx in forum Off-Topic
    Replies: 39
    Last Post: 02-25-2003, 06:00 PM
  5. What Weight Oil Should I Use (More)
    By HK_M3 in forum 1992 - 1999 M3 (E36)
    Replies: 9
    Last Post: 07-27-2001, 05:55 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •