Results 1 to 17 of 17

Thread: Engine bogs down/loses power in heavy rain

  1. #1
    Join Date
    Oct 2012
    Location
    Plymouth, MI
    Posts
    37
    My Cars
    1993 BMW 850Ci

    Engine bogs down/loses power in heavy rain

    I have an 88 E24 (US, Auto) that is in good running condition. The engine runs great unless I have the displeasure of getting caught in heavy rain. If driving on the highway, the engine will begin to bog down and I lose power. It will run rough until I get to a spot where the road isn't covered in water (not talking inches here, but what you'd expect during heavy to moderate rain). Pushing on the accelerator only seems to bog the engine down further.

    My theory is that the O2 sensor that is just before the cat is getting wet somehow. Maybe the ambient air vent on the sensor itself is getting wet? Another theory is that that connector plug for the O2, which is deep in the engine bay, is getting wet somehow. This seems unlikely since the connector has shroud.

    Has anyone else experienced this? Any help would be greatly appreciated!
    Last edited by SharkTanks; 02-28-2014 at 01:34 PM.

  2. #2
    Join Date
    Nov 2005
    Location
    Brookfield,CT
    Posts
    1,755
    My Cars
    '92 325IC '88 635
    When was the last time you checked inside distributor cap and rotor. If there are any cracks, even slight ones, carbon can track and so can water. Could be o2 sensor too but it would have to be the wiring. If it was the sensor itself, it would do it all the time.
    '88 635, '92 325IC, '99 323

  3. #3
    Join Date
    Oct 2012
    Location
    Plymouth, MI
    Posts
    37
    My Cars
    1993 BMW 850Ci
    I haven't, to be honest. I bought the car in Sep. of 2012 and that's one of the few things I didn't inspect. Thanks for the advice! I'll take a look and report back.

  4. #4
    Join Date
    Sep 2007
    Location
    Redwood City, ca, USA
    Posts
    311
    My Cars
    1986 635 CSi & 2001 525i Wagon
    How soon after you get out of the rain does it run right again?

  5. #5
    Join Date
    Jul 2010
    Location
    Columbus, ohio
    Posts
    567
    My Cars
    2000 540i/A
    On my way to work today my car started bogging down, and eventually backfiring and then it wouldnt even stay running. I unplugged the o2 sensor and its better, I just have to drive WOT for a smooth acceleration. We had a snow storm today, and I suspect maybe something got wet. If thats the case, what are the chances the o2 sensor is OK, and that it just needs to dry out? Or is it if it gets wet, I must buy a new one, type deal?

  6. #6
    Join Date
    Dec 2006
    Location
    Atlanta
    Posts
    4,006
    My Cars
    B9 coupe and B9 sedan
    I doubt the o2 is the issue. With it unplugged, the system will go rich. This can damage the catalytic converter so I would suggest that you hook it back up. Did you check the cap and rotor as previously recommended? I think you have basically ruled out the o2 sensor wiring as you can tell now that it was operating. It really is not that difficult to check. I guess you could go ahead and replace the o2 if you are really convinced that is the issue: it won't hurt anything.

  7. #7
    Join Date
    Oct 2012
    Location
    Plymouth, MI
    Posts
    37
    My Cars
    1993 BMW 850Ci
    Quote Originally Posted by ldk View Post
    How soon after you get out of the rain does it run right again?
    Almost immediately. If I can get out of a rain soaked street, everything runs as normal.

    - - - Updated - - -

    Quote Originally Posted by alpinacsi View Post
    I doubt the o2 is the issue. With it unplugged, the system will go rich. This can damage the catalytic converter so I would suggest that you hook it back up. Did you check the cap and rotor as previously recommended? I think you have basically ruled out the o2 sensor wiring as you can tell now that it was operating. It really is not that difficult to check. I guess you could go ahead and replace the o2 if you are really convinced that is the issue: it won't hurt anything.
    Yeah, I won't run the car with it unplugged. If the O2 were bad, it would always be an issue and I assume I'd get bad gas mileage. It's really only when driving through wet streets on the hwy. Given the location of the sensor itself, I would think this is the culprit. However, I'm still going to check the distributor cap housing this weekend for cracks.

  8. #8
    Join Date
    Oct 2012
    Location
    Plymouth, MI
    Posts
    37
    My Cars
    1993 BMW 850Ci
    Quote Originally Posted by carsnplanes View Post
    When was the last time you checked inside distributor cap and rotor. If there are any cracks, even slight ones, carbon can track and so can water. Could be o2 sensor too but it would have to be the wiring. If it was the sensor itself, it would do it all the time.
    Well...I inspected the cap over the weekend. No dice. It actually looks like it's been replaced not so long ago.

    From what I've read through various forums, I still feel like the O2 sensor is getting drenched and causing it to not return the correct voltage. If anyone else has any experience with these symptoms, I'm all ears. Thanks!

  9. #9
    Join Date
    Mar 2008
    Location
    Killeen TX
    Posts
    2,488
    My Cars
    1977 320i-s, 1986 635csi
    couple things to check:

    TPS switch
    AFM connector

    I had something else on m y mind for this but brain not worky right
    E21 Legion and proud member
    No dash to cracked, No shimmy to strong!
    RIP 1976 316 charbel is picking your parts from his teeth
    1977 320i
    1986 635csi
    1983 320is, parted for the 77
    2012 BMW G650GS Sertao
    Wife's:
    2007 Suzuki SV650
    1989 535 with manual swap
    1993 740i

  10. #10
    Join Date
    Mar 2009
    Location
    Melbourne, Victoria, Australia
    Posts
    235
    My Cars
    1986 BMw 635 CSi
    I have also suffered very similar symptoms driving in heavy rain, but not just normal driving. Its only after I drive through a large pool or puddle of water when water sprays up into the engine area.


    The car just dies, usually gradually, and there is simply no throttle response. I need to park, wait a few minutes, and then it starts again. Sometimes it will idle but will have no throttle response until something dries out.

    I have not confirmed the problem yet. I suspect it may be water getting into the bellhousing and affecting the crank position sensors. The fact I have a rear oil leak my be contributing by blocking draining in this area perhaps?


    Like others I suspect its not the O2 sensor. The computer should be going open loop and still running if this fails.

    Tony
    '86 635 that likes to stay dry

  11. #11
    Join Date
    Oct 2012
    Location
    Plymouth, MI
    Posts
    37
    My Cars
    1993 BMW 850Ci
    Quote Originally Posted by Tnarkowicz View Post
    Like others I suspect its not the O2 sensor. The computer should be going open loop and still running if this fails.
    Hmmm...interesting. I didn't think of that. Thanks!

    - - - Updated - - -

    Quote Originally Posted by pthm View Post
    couple things to check:

    TPS switch
    AFM connector

    I had something else on m y mind for this but brain not worky right
    Those will be my next to check!

  12. #12
    Join Date
    Mar 2016
    Location
    Skopje, Macedonia
    Posts
    1
    My Cars
    1997 ford ka
    What happend i have the same problem with my ford ka when driving on wet road. Please tell what can cause this stupid problem.

  13. #13
    Join Date
    Jun 2011
    Location
    NYC & Eastern Long Island
    Posts
    871
    My Cars
    '93 740il '84 633Csi
    Not sure this solves your problem, but the connection for the O2 sensor is at the TOP of the engine compartment zip tied to the firewall. It is the orange weatherproof connector just under the washer water line.

  14. #14
    Join Date
    Mar 2013
    Location
    Austin, Texas, USA
    Posts
    88
    My Cars
    1985 635Csi
    I have this problem and like Tnarkowicz it only happens when I drive through a large puddle fast. The funny thing is it will idle ok and never stalls but when I give it gas the engine can't develop any power. Let off the gas and it idles fine. It takes a few minutes idling until whatever it is dries out then it's normal again. I've never bothered to troubleshoot I just avoid the puddles.

  15. #15
    Join Date
    Sep 2017
    Location
    burlington, Vt
    Posts
    1
    My Cars
    2000 528i manny tranny

    Unhappy

    Quote Originally Posted by Mason Jones View Post
    I have this problem and like Tnarkowicz it only happens when I drive through a large puddle fast. The funny thing is it will idle ok and never stalls but when I give it gas the engine can't develop any power. Let off the gas and it idles fine. It takes a few minutes idling until whatever it is dries out then it's normal again. I've never bothered to troubleshoot I just avoid the puddles.

    I have an e39 528i with the same puddle problem. except yesterday i was pulling out of my driveway in normal dry conditions and my car did the whole loss of power gig. Just another curve ball being send my way. Gonna try a couple things week and hopefully post back if i sort it out.

    "winter is coming" -John Snow

  16. #16
    Join Date
    Apr 2008
    Location
    Greenwich, CT
    Posts
    2,018
    My Cars
    1985 BMW 635csi
    Had the same problem with my e34 and heavy rain. Changed the O2 sensor—problem solved.

  17. #17
    Join Date
    Jul 2008
    Location
    Boston, Ma
    Posts
    1,324
    My Cars
    86 635,72 E3, 88M6,73 E9
    Cap can have microfractures which cannot be seen unless you magnify.
    Rob E3

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
  •