Mystery Plug

Hey guys, my name is michael and i have recently bought a bmw 325e 1986 model, Ever since ive had the car it has had a very odd idle, it would jump slightly and drop down to its normal rev. I had a mechanic do a major service, changing muffler and rubbers in the steering column or something like that, the car was up on a hoist for well over 5 weeks. I have recently got the car back. Today i gave it a wash, my dad decided to take it out for a spin. When he got back the cars idle was sitting back at 2,000rpm and well over, it would drop to 1,500 and then jump back up to 2,000rpm then after a while it would drop to 1,000 rpm and drop to 1,500rpm and then back to the 2,000. I have no clue what is wrong with it. The mechanic claimed my engine was good. But with a little backyard try and fix it jobs, Me and my father discovered a loose plug that wasnt in its jack. This plug is on the left side on the engine bay, attached to another plug in the air intake. It is very short and must belong to somewhere near the left side of the engine or near the intake or radiator. I somehow think that this plug was loosely fitted when i bought the car, and on the drive it must of poped off. I think This plug has to do with the cars ecu computer control. Maybe the ecu doesnt find the car and is lost, this is maybe why its just lost in the revs, ur help would be apprichiated, i will how ever take it to the mechanic tomorrow but it would help with my pocket cause im currently 16 and have a low paid job. I've spend over 1,000 australian dollars on serivce and insurance so i dont have much money to thrown around, thanks guys :)

michael

If you got an idle like that your Idle air control valve is done or the connection on it. It sits in the throtel body.
Try disconnecting it and see what happens. Maybe it just needs cleaning. This connector you describe might belong to the the valve (check it).

Thanks mate, just before i had my uncle over and he played around with the throttle body, he fixed it :D but thanks alot. I also think the throttle body has had it and i will be taking it to bmw and changing it this weekend and also to do an overall check up on it. THanks alot brother ur help was much apprechiated, i was gonna reply to say not to warry but ur too quick but thanks again mate

michael

If your thinking of changing out the throttle body just have it cleaned. I know most cars have a TPS (throttle positioning sensor) which gets stuck with carbon buildup. It's just a float on a small shaft that moves up and down depending on heat from the engine. You could probably take the throttle body off and clean is with some carb or choke cleaner and that should do the trick from future mishaps. If you're 16, start working on it now. By the time your my age, 29, you"ll have a real good understanding of most cars. i have found out that my BMW's aren't too much off of how an American engine is designed and problems that they face. So get a grasp of it now, especially with BMW's. I'm a BMW man for life now. I'm on my 3rd one and I do all the maintence myself. Some stuff I just don't care to tackle becuase of tools or garage space, or cost. So take it from there. Throttle body is a good start. It's really easy.

Thanks, The throttle body is finished off. The car revs like its on something :S. Im also hooking it up to a computer to check if everything is in running order. I was wondering if its possible to fit the 325i throttle body to a 325e. and if soo is their any porformance or good out of doing so?
thanks ill try and clean it :)
Im a bmw fan for life aswell ever since my dad bought his 2000 bmw e46 330i. Best car ever so i found this 325e and i didnt miss the chance and leaped for it :)