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    #1

    Not your typical idle problem

    1988 325iC: bavauto chip, bavauto plug wires, K&N conical; otherwise engine is bone stock

    So I replaced my clutch about 2 weeks ago and ever since it's been idling rough at both hot and cold. To describe it let me say my car sounds like it has an awesome aftermarket cam, except that it doesn't and it sounds like ass. RPM is basically steady, but it knocks or misfires and shakes about. No hesitation on acceleration and no power loss or rough running at cruising speed. Since I've done all this work to it, it feels like it's 3X more powerful than before, except for the crappy idle.

    I've been running through the possibilities but now I'm just stumped.

    Things I've already checked/replaced:
    -O2 sensor has about 6 miles on it, tests fine
    -airflow sensor tests fine
    -throttle sensor tests fine
    -IACV tests fine
    -spark plugs were replaced 3 hours ago so it's not them (cylinder 4 had some unburnt fuel on it and smelled vaguely like oil).
    -spark plug wires all have same resistance (about 5.6 ohms all around, is this safe range?)
    -distributor coil is fine
    -brand new battery
    -vacuum leaks are all sealed up or fixed
    -oil dip and oil cap are both brand new and not leaking
    -all gaskets on intake side are brand new
    -timing belt/water pump/belt tensioner were replaced about 30 miles ago

    I can't think of anything else it might be. Help me my DD doesn't like stop lights anymore!
    The Keystone Killers
    Originally posted by Cabriolet
    With 73k+ post, you'd think he'd have learned a little about life.
    Tags: None
    #2
    My first suspicion would be an intake leak if the only symptom is a rough idle, possibly aggravated by mis-adjusted valves.
    The car makes it possible, but the driver makes it happen.
    Jim Levie, Huntsville, AL

    Comment

      #3
      Temp sensor?????

      Comment

        #4
        Originally posted by ADEN View Post
        Temp sensor?????
        Do you know the check procedure for the temp sensor by any chance?
        The Keystone Killers
        Originally posted by Cabriolet
        With 73k+ post, you'd think he'd have learned a little about life.

        Comment

          #5
          Originally posted by Radiocammbodia View Post
          Do you know the check procedure for the temp sensor by any chance?
          check with an ohm-meter, the resistance should vary with temp, but I don't know the specs off-hand
          1989 cirrisblau-metallic 325i

          Comment

            #6
            Originally posted by SpecM View Post
            check with an ohm-meter, the resistance should vary with temp, but I don't know the specs off-hand

            Does bentley cover the procedure?

            I noticed today the check engine light comes on, but only at idle, not while driving or accelerating.
            The Keystone Killers
            Originally posted by Cabriolet
            With 73k+ post, you'd think he'd have learned a little about life.

            Comment

              #7
              Maybe cold-start injector issue? This may appear in fuel mileage, too. How far apart did you have everything/what could have been disturbed? Did you wash the motor prior to working on it? Possibly cracked or defective plug? (new or not...)
              sigpic

              Mike

              '91 325i track car. Mostly...

              Comment

                #8
                Originally posted by Knockenwelle View Post
                Maybe cold-start injector issue? This may appear in fuel mileage, too. How far apart did you have everything/what could have been disturbed? Did you wash the motor prior to working on it? Possibly cracked or defective plug? (new or not...)
                The idle is slightly better at cold, I figured that was the extra fuel being dumped. Maybe a fuel issue (clogged fuel filter)?

                I did have to disconnect the electricals on the fuel injectors, I'm sure they're back in the right order though.

                I had to take the intake plenum off to get at the last bolt way on top of the trans, it had corroded itself in there and had to be replaced. I replaced all the gaskets for the plenum though.

                No, I didn't wash the motor. I'm thinking the valves may be out of adjustment, so I'm going to take it into the local euro shop to check it out. I still have to check the temp sensor though.
                The Keystone Killers
                Originally posted by Cabriolet
                With 73k+ post, you'd think he'd have learned a little about life.

                Comment

                  #9
                  Originally posted by Knockenwelle View Post
                  Maybe cold-start injector issue? This may appear in fuel mileage, too. How far apart did you have everything/what could have been disturbed? Did you wash the motor prior to working on it? Possibly cracked or defective plug? (new or not...)
                  no cold-start injector on is car
                  1989 cirrisblau-metallic 325i

                  Comment

                    #10
                    Sounds like a vacuum leak to me. Did you check the main rubber intake hose? Possibly cracking on the bottom or somewhere you can't see it?

                    Comment

                      #11
                      And check the little tiny rubber hose that goes to the bottom of the throttle body that comes from charcoal canister. definatly sounds like intake or vaccum leak.
                      sigpic
                      mods: just meat and potatoes under the hood and wheaties on fire out back ;)

                      Comment

                        #12
                        buy some carb or brake cleaner and spray it around the air boots with the engine idleing. Listin for changes, this will indicate vacuum leaks.

                        Good luck, my air boot has a rip, and misses at high rpms (engine shifts under high load and exposes a small crack on it), it only $23 on Pelican.
                        1989 cirrisblau-metallic 325i

                        Comment

                          #13
                          I have the exact same problem...I mean EXACT! I have adjusted valves and new gasket on the valve cover, that overed a small leak there aswell, I changed the O2 sensor and plugs, wires, cap, rotor, coil is fine, timing aswell is checked, the shop I went to checked again for vacuum leaks and nothing...but I see here something about temp sensor, shy off sounding stupid how does this compnent affect the engine if it fails..I will check for more cracks. Oh and now I hear low speed clutch chatter is that something your having to RADIOCAMMBODIA and a slight whine under the hood aswell. Let me know how it goes and offer any advice if you find the fix.
                          sigpic

                          Comment

                            #14
                            does it sound like this
                            http://www.youtube.com/watch?v=lpKHaFBsTQA


                            maybe your ignition wires are mixed up?
                            Your signature picture has been removed since it contained the Photobucket "upgrade your account" image.

                            Originally posted by TimKninja
                            Im more afraid of this thread turning into one of those classic R3v moments, where Pizza gets delivered.

                            Comment

                              #15
                              Originally posted by NC325iC View Post
                              does it sound like this
                              http://www.youtube.com/watch?v=lpKHaFBsTQA


                              maybe your ignition wires are mixed up?
                              No it sounds perfectly normal once I apply any throttle, with no loss of power or anything, it just idles like crap.

                              I had a shop hook up a smoke machine to find any leaks and the only spots were the throttle body connection for the IACV and the brake booster hookup, both are sealed now.

                              I'm going to check temp sensor today and I'll get back with details on that. Otherwise I'm thinking valves, and I'll take it in for adjustment.

                              My 2 day clutch job has turned into a 2 month marathon of crap.

                              Edit: Let me see if I can record the sound for you guys.
                              The Keystone Killers
                              Originally posted by Cabriolet
                              With 73k+ post, you'd think he'd have learned a little about life.

                              Comment

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