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Fixed an E30 idle issue today

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    Fixed an E30 idle issue today

    I feel like I should celebrate or something.

    I have been fighting an idle issue with a new (to me) 89 325is for the past month. I would start the car and it would idle at 700rpm for about 10-15 seconds then drop-out sometimes cleaning back up and sometimes stalling out requiring re-start. Placing the car in reverse (automatic) the car would sputter and try to die. Once under speed the car would run, but anytime you came to a stop the car would try and die. So I did all the typical steps of
    cleaned the ICV with MAF cleaner, inspected the intake hose for cracks (none, looked great), replaced the TPS and adjusted it, changed-out the AFM for a known good one, checked all my vaccum lines, double checked my vacuum lines again. Arghh, still sputtering and cutting out!!

    I was getting ready to start looking at the fuel pressure/fuel pump/fuel injectors as a next step, but decided to pull everything off one more time.
    In the process these are the only things I did.
    1) Added a fresh air filter to the air box.
    2) Put new plugs in the car (none were oil fouled, just a bit of crud on them but looked pretty decent for a high mileage car)
    3) Pulled my throttle body again and double checked my TPS adjustment which was good and required no adjustment.
    4) Put everything back together, but this time went the extra step to wrap some teflon tape around the three fittings that insert into the throttle body (1 coming from the ICV on the left side of the t-body and 2 for the brake booster coming out of the right side of the t-body).

    After this effort I started the car and I had a solid idle. Let it run for a bit and revved it a bit no sputtering. At this point I turned the car off and decided I would try again later. Two hours later I got the same results. At this point I was getting optimistic but felt that it was surely some kind of fluke and still didn't take it out for a drive. This evening I started it a third time and all was good again. I put the car in reverse and dead solid with no sputtering or dying. Took it for a spin and it ran fine the entire drive even when coming to a stop.

    So...based on the results of everything I have tried I truly believe my issues were related to those little press-fit aluminum fittings being loose in the throttle body and allowing air to be pulled-in causing sporadic sputtering and overall poor idle and performance.

    Just wanted to share that experience as anyone else that is fighting an idle gremlin with their e30 might want to check those fittings and try the teflon tape trick to see if it helps. Teflon tape is really cheap and if it works you have saved a bit of money.

    Jeff

    #2
    Did any of yours seem really loose?

    My brake booster ones come half unplugged on their own... I hadn't thought that these could be really causing a problem, I'll have to take a look now. Thanks for sharing.
    Thanks,
    Matt

    Check out my BMW Fault Code Index
    '89 Turbo M20 Zinno Cabrio (scrapped)
    '89 Zinno IX (sold)
    '91 Granit Turbo S52 Sedan (scrapped)
    '91 WIP (scrapped)
    '13 F10 Carbon Black 550iX MSport
    '91 iX Sedan

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      #3
      Originally posted by MattPro View Post
      Did any of yours seem really loose?

      My brake booster ones come half unplugged on their own... I hadn't thought that these could be really causing a problem, I'll have to take a look now. Thanks for sharing.

      All three of mine would slide out fairly easily. I noticed one of the two feeding the brake booster sitting a little unseated and this is what made me consider it as a culprit. I wrapped each one of the fittings with a full wrap and half around the fitting circumfrence with the teflon tape and then pressed it in and leveraged it into the side of t-body with a plastic screwdriver handle. Not sure how long it will last, but for now it seems to be making a major difference.

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        #4
        Originally posted by N10S View Post
        All three of mine would slide out fairly easily. I noticed one of the two feeding the brake booster sitting a little unseated and this is what made me consider it as a culprit. I wrapped each one of the fittings with a full wrap and half around the fitting circumfrence with the teflon tape and then pressed it in and leveraged it into the side of t-body with a plastic screwdriver handle. Not sure how long it will last, but for now it seems to be making a major difference.
        Yep I'll probably be doing this first thing tomorrow then, that is exactly how mine are. They're all kind of loose but the lower break booster one likes to stick out a little.

        On some other cars I've seen those things are almost impossible to get off. I wonder if this is an issue with the connectors or the throttle body housing itself. I hope it's just the connectors, I just replaced my TPS so I'd hate to lose it. (It doesn't seem like you can take the replacement one I bought off without destroying it).
        Thanks,
        Matt

        Check out my BMW Fault Code Index
        '89 Turbo M20 Zinno Cabrio (scrapped)
        '89 Zinno IX (sold)
        '91 Granit Turbo S52 Sedan (scrapped)
        '91 WIP (scrapped)
        '13 F10 Carbon Black 550iX MSport
        '91 iX Sedan

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          #5
          Could you take a quick pic and post it? I'm trying to picture these areas....could you not put a worm type clamp around each area?
          1997 Artic Silver M3
          CES GT4094r 651hp/615tq @ 24 psi

          Comment


            #6
            Originally posted by Alexis Jung View Post
            Could you take a quick pic and post it? I'm trying to picture these areas....could you not put a worm type clamp around each area?
            Here's a quick picture I found after googling, it's the one hose on the left and the two on the right (with all the orange stuff on it) of the throttle body.
            EDIT: used some ms-paint skills
            Thanks,
            Matt

            Check out my BMW Fault Code Index
            '89 Turbo M20 Zinno Cabrio (scrapped)
            '89 Zinno IX (sold)
            '91 Granit Turbo S52 Sedan (scrapped)
            '91 WIP (scrapped)
            '13 F10 Carbon Black 550iX MSport
            '91 iX Sedan

            Comment


              #7
              I see....I checked out some other google pics (thank you!) and looks like there are some one time BMW clamps.....again, I would use the small worm clamps to really ensure a snug fit
              1997 Artic Silver M3
              CES GT4094r 651hp/615tq @ 24 psi

              Comment


                #8
                Originally posted by Alexis Jung View Post
                I see....I checked out some other google pics (thank you!) and looks like there are some one time BMW clamps.....again, I would use the small worm clamps to really ensure a snug fit
                The part that comes loose is not the hose to metal fitting union, its the metal elbow fittings that press fit inot the throttle body. There is no way to get a hose clamp on that. The hose is not the issue. Thats the misleading part of this problem. The visuals on the hose and clamp can be good, but if the fitting is loose in the throttle body it will suck in air. Those pics show those fittings inserted into the throttle body as they are supposed to be, but mine were actually easy to pop out and were working there way out of the throttle body. Thanks for the photo MattPro!

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                  #9
                  i've used #2 permatex non hardening sealer in the past with great results
                  sigpic

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                    #10
                    jb weld ftw

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                      #11
                      That is a very common problem. My fix for that is to clean the nipples and sockets with acetone and JBWeld the elbows in (with the throttle body mounted). Let that set up overnight and you have a permanent fix.
                      The car makes it possible, but the driver makes it happen.
                      Jim Levie, Huntsville, AL

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                        #12
                        Originally posted by jlevie View Post
                        That is a very common problem. My fix for that is to clean the nipples and sockets with acetone and JBWeld the elbows in (with the throttle body mounted). Let that set up overnight and you have a permanent fix.
                        JB weld is a great product for this sort of thing so I may go that route for my "permanent" fix. Thanks to you an e30trooper both on that one. The # 2 permatex non hardening sealer mentioned by bmwstudent sounds like a good option too so I need to consider both I suppose.

                        I bought this 325is for my son and after about a month of futzing around with the car trying to get it to run right he has finally had the chance to test drive it today and was all smiles!! I have been wrenching on old BMW's since the early 80's but with this 325is problem I have to really give credit to a great forum with a wealth of information just waiting at the press of the search button. Thanks folks!!!

                        Jeff

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                          #13
                          Those hoses that are attached are also a good area for vacuum leaks to develop. My smoke test proved those clamps were loose over time and smoke was coming out of the vacuum hoses directly attached to the TB.
                          Owner - Bavarian Restoration
                          BMW and European Electronics Repair and Restoration
                          www.BavRest.com
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                            #14
                            Those 1 time BMW clamps should all be replaced with worm clamps
                            1997 Artic Silver M3
                            CES GT4094r 651hp/615tq @ 24 psi

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