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  1. #1
    Established Member Two Rings
    Join Date
    May 28 2016
    AZ Member #
    373939
    Location
    Lake Arrowhead

    B7 05.5 S4. Misfire-Unresolved

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    Hey guys, turning to here to try and see if someone can help me figure out this S4.
    I replaced the intake manifold due to the flap actuator being completely seized, along the way, i also replaced the valley pan gasket with the oil filter housing gasket since it was leaking.
    After re-assembly, the car still has the same misfire codes, cyl 1-3 and 7. The ignition coils and spark plugs were replaced, i checked the park plugs and they seemed a bit burned, but nothing to be concerned with.
    I also swapped the coils and plugs from bank to bank 1-4 2-5 3-6 4-8. Still the same cylinders are still misfiring, and I am still hearing backfire coming from the intake (with the MAF unplugged the backfire stops, but MAF readings read fine when plugged in). The misfire is only at idle. anything above 1k-1.2k+ and no misfire.
    there is still a strong smell of fuel coming from bank 1, while bank 2 didnt smell that bad. (issue that carried over with the intake manifold swap, which came with injectors of its own).
    Tomorrow im going to take off the intake manifold and swap the gaskets, along with possibly the spark plugs. But something is telling me this isnt a spark plugs issue.
    Would love some input on this!

  2. #2
    Established Member Two Rings
    Join Date
    Jun 21 2018
    AZ Member #
    421051
    Location
    Alabama

    Can you read codes from the OBD II port? That would help. Misfires at idle make me wonder about the mechanical cam adjuster failing.

  3. #3
    Established Member Two Rings
    Join Date
    May 28 2016
    AZ Member #
    373939
    Location
    Lake Arrowhead

    At first i used vag com and it gave me fuel trim fault codes, and misfires.
    After intake swap, i only used the snap on scanner, and it read
    Multiple misfire.
    Misfire cylinder 3- limit reached.
    And the same for the other cylinders.
    After i clear the codes, only misfire that comes back as a hard fault is cyl 3. But if i drive the car, the other cylinders show up as well.
    No timing codes what so ever.

    When i had vagcom, adv. Mes. Val. 93 gave me 2 readings, one was at a very high 43%? And the 2nd measure was low, around 11% if i remember correctly.

  4. #4
    Senior Member Four Rings Dondbg's Avatar
    Join Date
    Mar 12 2016
    AZ Member #
    370140
    My Garage
    MB w203, B6 S4
    Location
    New Zealand

    B7 05.5 S4. Misfire-Unresolved

    I bought an s4 that was backfiring through the intake and running really rough, earlier symptoms as described by previous owner was lose of power. Then I discovered the engine actually jumped time. Scan the car with VCDS should give you some clues. My advise would be if itís timing related not electrical then donít drive it and get it fixed, the one I have this happened to it and explains the backfiring.




    Edit: and I had timing codes

  5. #5
    Established Member Two Rings
    Join Date
    May 28 2016
    AZ Member #
    373939
    Location
    Lake Arrowhead

    Quote Originally Posted by Dondbg View Post
    I bought an s4 that was backfiring through the intake and running really rough, earlier symptoms as described by previous owner was lose of power. Then I discovered the engine actually jumped time. Scan the car with VCDS should give you some clues. My advise would be if itís timing related not electrical then donít drive it and get it fixed, the one I have this happened to it and explains the backfiring.




    Edit: and I had timing codes
    Did you buy the car with timing codes?
    Ive put about 2000 miles on the car since i bought it, and ive not once had it give me any timing codes. Just misfire codes, and only on 1, 2, 3 and 7. So thats where its making me question. Im seriously hoping its not the chains, but realistically im not seeing a different solution to this

  6. #6
    Senior Member Four Rings Dondbg's Avatar
    Join Date
    Mar 12 2016
    AZ Member #
    370140
    My Garage
    MB w203, B6 S4
    Location
    New Zealand

    Quote Originally Posted by Azdramos View Post
    Did you buy the car with timing codes?
    Ive put about 2000 miles on the car since i bought it, and ive not once had it give me any timing codes. Just misfire codes, and only on 1, 2, 3 and 7. So thats where its making me question. Im seriously hoping its not the chains, but realistically im not seeing a different solution to this
    Mine got no misfire codes which is very strange
    Yes I bought it with the fault codes, I kinda knew what I got myself in to.

    Good luck.

  7. #7
    Established Member Two Rings
    Join Date
    May 28 2016
    AZ Member #
    373939
    Location
    Lake Arrowhead

    Quote Originally Posted by Dondbg View Post
    Mine got no misfire codes which is very strange
    Yes I bought it with the fault codes, I kinda knew what I got myself in to.

    Good luck.
    I thought so too! Since the intake manifold flap was seized, figured thats what was causing the misfires at idle.

  8. #8
    Senior Member Three Rings roboto_1337's Avatar
    Join Date
    Jul 05 2016
    AZ Member #
    375740
    My Garage
    2006 S4 6MT
    Location
    Ontario, Canada

    Could a clogged cat cause this? maybe for 1-2-3 but don't know about 7... different bank. Check the harness too?
    Piggy Pipes, Milltek non-res cat-back exhaust, JHM 93 Tune, JHM Short Throw Shifter, Updated RS4 upper and lower timing guides, Brembo 18Z w/RS4 SS lines, Hotchkiss RS4 Front Anti-sway bars, BC racing BR coilovers, EB-Works adjustable rear end links, 034 Motorsports spherical end links. 034 Motorsport Engine mounts, 034 Motorsports Silicon MAF hose, Hartmann 19" RS4 Reps +5mm 42DD front +10mm ECS rear.

  9. #9
    Established Member Two Rings
    Join Date
    May 28 2016
    AZ Member #
    373939
    Location
    Lake Arrowhead

    Quote Originally Posted by roboto_1337 View Post
    Could a clogged cat cause this? maybe for 1-2-3 but don't know about 7... different bank. Check the harness too?
    Well, the car doesnt have cats, just piggy backs from previous owner. I suspect it has an exhaust leak somewhere on bank 1 side. (car is ridiculously loud, so its hard to tell)
    Also the fuel smell coming from bank 1 is curious.

    All connectors seem perfectly fine, along with the injector connectors (which can brake by just looking at them)

  10. #10
    Senior Member Three Rings
    Join Date
    Jan 05 2010
    AZ Member #
    52966
    Location
    burnaby british columbia

    Sorry to say this,its timing guide time for you . Had same thing on my car , whole passenger bank misfiring with cyl 3 being the worst. So called pro mechanics had it diagnosed as wiring harness , then injectors etc. Ended up being center guide broken.



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