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S50 wierd noise. Help Diagnose (vid)

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    #46
    Originally posted by nrubenstein View Post
    Measure the temperature of the header tubing. You can check for spark and fuel, but a cold (really, just noticeably cooler - it'll still get hot) tube is indicative.

    And no, the car should not run roughly because the DME has been disconnected.
    That's how I figured out which of my coils I left the bolts loose on. A VERY quick touch with my finger on each runner revealed the dead cylinder. The one that didn't sizzle my skin when I touched it was the dead one lol.

    My car sounded like a Subaru flat four with a loud exhaust when it was missing on one cylinder FWIW I wasn't even sure it was missing until I checked.

    '89 Alpine S52 with goodies

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      #47
      I give up... I feel like taking it to a shop now.

      I opened up the valve cover. Put in new Sprk plugs, retimed the cams and Vanos - and it still has a rough feeling at around 1500.

      In fact, I didnt even drive it 2 blocks, and it died on me and made a sound like I bent some valves. Luckily, it turned back on, and I could make it back home in the garage. But I am spent at this point.

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        #48
        loose ground?

        check for a bad ground....that was the unknown problem with my friends rough idle and random electrical problems. he replaced every sensor including o2 (engine code for o2) and even ecu. then we noticed the loose ground cable...it ran smooth and no more noises...good luck

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          #49
          The car actually idles great - its the shaking in the cabin b/w 1250-3000 rpms that is bothering me now. At idle, the car feels fine, and if you rev it from the throttle body, the engine sounds just fine.

          The problem is that the cabin is shaking b/w those low rpms. I did some more reseach and found that it could be one of the bearings that the main belt goes around (PS pulley bearing or Alternator bearing), or it could be DMF (what is this?)/clutch/flywheel.

          The vibration happens when the car is sitting still or driving.

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            #50
            Originally posted by Adrian_Visser View Post
            That's how I figured out which of my coils I left the bolts loose on. A VERY quick touch with my finger on each runner revealed the dead cylinder. The one that didn't sizzle my skin when I touched it was the dead one lol.

            My car sounded like a Subaru flat four with a loud exhaust when it was missing on one cylinder FWIW I wasn't even sure it was missing until I checked.
            I used a pyrometer. :)
            2006 GMC Sierra 2500HD 4WD LBZ/Allison
            2002 BMW M3 Alpinweiß/Black
            1999 323i GTS2 Alpinweiß
            1995 M3 Dakargelb/Black
            - S50B32/S6S420G/3.91
            1990 325is Brilliantrot/Tan
            1989 M3 Alpinweiß/Black

            Hers: 1996 Porsche 911 Turbo Black/Black
            Hers: 1988 325iX Coupe Diamantschwartz/Black 5spd

            sigpic

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              #51
              We had that talk about the lifters.... Have you dealt with those yet???
              Past Car : E30 S50 6 Speed 5 Lug 3.73
              Current : Z3 S50 OBD2 (Smog Legal) 6 Speed BBS RN Dual Ear Diff
              ___________________________________________
              BNB Designs
              Engine Swaps, Fabrication, Innovation, General Repair
              Richmond CA
              Julian 848-248-8029

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                #52
                What I have recently discovered is that the bad sound in the video is gone. I think it was the Vanos the entire time and not letting the engine idle enough and pump oil around. The reason I think it was the vanos is because I rebuilt it, and it had no oil in it when installed. I cleaned it with brake parts cleaner entirely and then installed it.

                Once enough oil was pushed all around the engine, the motor was back to quiet (plus I retimed it, since it was a little off).

                Now, I believe I am dealing with a clutch/flywheel issue with the vibration in the cabin at 1200-2900 rpm.

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