Close

Results 1 to 14 of 14
  1. #1
    Join Date
    Nov 2010
    Posts
    404
    Rep Points
    758.8
    Mentioned
    11 Post(s)
    Rep Power
    8


    Yes Reputation No

    Advice re: coil pack (or injector)?

    Midway through my third 25-minute session at a road course today (Summit Point), my car -- a 1M with 41,000 miles -- developed a "hitch" under heavy throttle and would not rev smoothly past 6,200.

    Initially, it would stumble only in third gear, and at times felt like it was hitting a rev limit. Sometimes it seemed to last for 3-4 seconds, and would eventually make it way past the rough spot and resume accelerating. And sometime it would rev right on to redline without a hitch, even in 3rd gear.


    After experiencing this 5-6 times, I also began to detect a roughness and loss of acceleration in 4th gear. Also, the range it which it was stumbling seemed to widen to approx. 5,800-6,200.


    I brought the into the paddock to check for codes after this happened several more times over 2-3 laps. Surprisingly, according to my to-date completely reliable P3 vent gauge, there were no codes.


    I suspect a failing coil pack because this only happened under heavy load under track conditions on a humid 90 degree day. Although my oil and coolant temps were fine, I figure that heavy usage and high under hood temps may have caused a tiny fracture in a coil pack. FWIW, I had no problem accelerating through the gears under far less stressful conditions on my drive home.


    Although the problem could be caused by spark plugs, I'm ruling that out since they were replaced just 1,300 miles ago.


    But before I fix on the coil packs (which I can replace for about $300), is there any chance the issue might be a dirty/clogged injector?


    I appreciate your advice/suggestions about how I might proceed.

    Thanks.


    Neil
    Last edited by MDORPHN; 09-01-2013 at 08:23 PM.

  2. #2
    Join Date
    Jul 2011
    Location
    Boston
    Posts
    78
    Rep Points
    67.0
    Mentioned
    0 Post(s)
    Rep Power
    0


    1 out of 1 members liked this post. Yes Reputation No
    A code would really help, it would be a waste to replace all the coils without a misfire code. Does the vent gauge read shadow codes also?

    Could be a bad plug even though they are new, bad injector, bad coil, even vanos solenoids could need cleaned or even carbon buildup.

    I would probably drive it until it threw a code and had a bit more to chase it down, he'll could even just be some poor gas if it doesn't throw a code a goes away.

    good luck with it.

    rob
    2008 E93 Giac Stage 2, HPF IC, Injen Intake, Defective AR Design DP's with useless cats
    2014 X3 35i JB Stage 1

  3. #3
    Join Date
    Jul 2011
    Location
    Boston
    Posts
    78
    Rep Points
    67.0
    Mentioned
    0 Post(s)
    Rep Power
    0


    1 out of 1 members liked this post. Yes Reputation No
    Thought of one more thing, since you had the plugs out recently, check the grounds for the coils are all tight and ground wires are in good condition and have no damage, I have seen a loose ground on a coil one time cause some issues.
    2008 E93 Giac Stage 2, HPF IC, Injen Intake, Defective AR Design DP's with useless cats
    2014 X3 35i JB Stage 1

  4. #4
    Join Date
    Nov 2010
    Posts
    404
    Rep Points
    758.8
    Mentioned
    11 Post(s)
    Rep Power
    8



    Yes Reputation No
    Thanks.

    Yeah, no codes whatsoever. Very odd.

    Walnut blasted the valves 10,000 miles ago and had replaced the vanos solenoids a bit farther back.

    Running the original coil packs, so I'm figuring one (or more) has reached the end of its useful lifetime and will be replacing them.

    Nel

  5. #5
    Join Date
    Jul 2011
    Location
    Boston
    Posts
    78
    Rep Points
    67.0
    Mentioned
    0 Post(s)
    Rep Power
    0


    Yes Reputation No
    Could be but you should get a misfire shadow code and then you can move the coil pack to a different cylinder to verify it is the coil vs the plug or injector.
    2008 E93 Giac Stage 2, HPF IC, Injen Intake, Defective AR Design DP's with useless cats
    2014 X3 35i JB Stage 1

  6. #6
    Join Date
    Mar 2012
    Location
    Cleveland TN
    Posts
    542
    Rep Points
    555.0
    Mentioned
    16 Post(s)
    Rep Power
    6


    Yes Reputation No
    Typically any true misfire should trigger a code. I've had cars give misfire codes even when there weren't that noticeable. What mods do you have done to the car?
    2008 135i - Cobb AP, JB4 G5 w/2Step&FSB, MS DP's, Berk street exhaust, AMS IC, VTT Inlets, UR Intake, ER CP w/Tial BOV, Spec 3+ & Steel FW, CDV delete, Quaife LSD, DSS Axles, M3 control arms, M3 rear SF bushings, M3 Trans bushings, SS brake lines. Pics

  7. #7
    Join Date
    Nov 2010
    Posts
    404
    Rep Points
    758.8
    Mentioned
    11 Post(s)
    Rep Power
    8



    Yes Reputation No
    I'm now leaning toward a fuel pump issue. In fact, when it first occurred on track, I recall glancing at my fuel gauge 'cause it did feel like fuel starvation. And it didn't feel rough/sharp like a misfire, more like the motor simply temporarily losing power.

    Plus it was occurring at peak torque, presumably when the demands on the fuel delivery system are the greatest.

    Should this possibly early sign of a failing fuel pump have thrown codes?

    Thanks.

    Neil

  8. #8
    Join Date
    Sep 2012
    Location
    Huntsville, AL
    Posts
    144
    Rep Points
    263.5
    Mentioned
    1 Post(s)
    Rep Power
    3


    Yes Reputation No
    Sounds like a fueling issue to me. Are you running any E85 or just pump gas? Also do you have any logs during your track time? Or do you think you could recreate the problem and get some logs, that could help out a lot in determining the problem. Heck it could be an O2 sensor going bad.
    07 335i FFTEC 600 Click here to enlarge

  9. #9
    Join Date
    Nov 2010
    Posts
    404
    Rep Points
    758.8
    Mentioned
    11 Post(s)
    Rep Power
    8



    Yes Reputation No
    Click here to enlarge Originally Posted by wtfmarine Click here to enlarge
    Sounds like a fueling issue to me. Are you running any E85 or just pump gas? Also do you have any logs during your track time? Or do you think you could recreate the problem and get some logs, that could help out a lot in determining the problem. Heck it could be an O2 sensor going bad.
    93 pump.

    Regret that I wasn't logging, but may log some wot 3rd gear pulls tonight.

    O2 sensors are new.

    Neil

  10. #10
    Join Date
    May 2012
    Location
    Jacksonville, FL
    Posts
    2,942
    Rep Points
    2,873.1
    Mentioned
    78 Post(s)
    Rep Power
    29


    Yes Reputation No
    I recall @enrita had fuel starvation issues on hard cornering. Perhaps you are experiencing the same issue?
    2011 E90 M3 \ Melbourne Rot Metallic

    Click here to enlarge

  11. #11
    Join Date
    Nov 2010
    Posts
    404
    Rep Points
    758.8
    Mentioned
    11 Post(s)
    Rep Power
    8



    Yes Reputation No
    Click here to enlarge Originally Posted by lulz_m3 Click here to enlarge
    I recall @enrita had fuel starvation issues on hard cornering. Perhaps you are experiencing the same issue?
    This wasn't in corners, but WOT on straights.

    Nonetheless, it felt very similar to the fuel starvation I've experienced in others cars when cornering hard with low fuel.

    Neil

  12. #12
    Join Date
    Mar 2013
    Posts
    21
    Rep Points
    77.9
    Mentioned
    2 Post(s)
    Rep Power
    0


    Yes Reputation No
    I had a similar issue that was a coil, it did throw a code though. Currently looking into plasma coils to prevent if from being a future issue.

  13. #13
    Join Date
    Nov 2010
    Posts
    404
    Rep Points
    758.8
    Mentioned
    11 Post(s)
    Rep Power
    8



    Yes Reputation No
    Could still be a coil pack, but another indication that it may be fuel delivery issue is that the exhaust tips -- which are usually black from running a conservative rich map -- look brown/grey, the color of happy spark plug electrode -- as if I was running lean.

    Neil

  14. #14
    Join Date
    Oct 2011
    Posts
    1,058
    Rep Points
    1,149.6
    Mentioned
    39 Post(s)
    Rep Power
    12


    Yes Reputation No
    Pulling the plugs will take a lot of the guesswork out of it.

Tags for this Thread

Bookmarks

Posting Permissions

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