Engine Idle

[leescot]

hi, I got a e46 3er for a year so far and the engine starts to have rough idle, it goes dwon and up when I stop at traffic lights, please help ! thank you

[jkloese]

First of all what year is it? How much deos it actually fluctuate? A rough idle can be many factors, from simple tune up things like spark plugs and wires to bent valves(major rough idle with that) Do you have any check engine lights? Deos it have any problem while excelerating? I think you will get alot more responses from us if you give more details. Let us know, we will try and help!

[leescot]

thanx, I got a 2003 E46 and the engine check light doesn't come on at all, it is just after a short drive, it does that and I can see it fluctuate from normal rpm and down to like 300 rpm and sometimes it stalls.... besides that, everything is fine (like excelerating)

[jkloese]

Well its still pretty new so I dont see the plugs being bad, but I have heard of alot of problems with coils in the e46. I personally havent had any problems with mine. Is your car under warranty? Im not one to bring my car to dealer...even for warranty work, just because I seem to have some problem every time I go. But this sounds more electricaly related (computer problem maybe?) and could end up costing alot unless you use the warranty. Hopefully somebody else can put some input in also. Good Luck!

[bryan1970]

even though the engine light hasn't come on yet it is still possible for the computer to have faults storred. the three things that come to my mind are and idle valve, gas pedal, or a throttle body, since that car is throttle by wire. idle valves are somewhta common to fail, and there is a problem with the engine wiringn harness that can sey fault for the throttle body. however usualy these problems will turn on the engine light. you should definatly try and get the faults read out of the computer, if there are any. if no faults are storred then it could be pretty tricky for the dealership or whom ever to diagnose the car. does it pretty much happen every time? how many times has it happened. if it has only happend a couple of times the computer may not have picked up on it yet and hasn't set a fault yet.

[leescot]

I went back to the dealership, they did all sorts of testings including error code read out and found out nothing is wrong including the coils and plugs(not faulty), then they searched BMW Canada tech. resources and found the solution for the rough idle thing

they raised the idle rpm (40 rpm) and re-programed the computer

does it sound right? I feel like I will use more gas with this settings...... please let me know if it sounds reasonable and your opinions, thanks.

and hopefully it could be helpful for someone else with the same problem

[jkloese]

Well thats the first Ive heard of that. I mean how could the computer have the idle value set wrong from the factory? So what RPM deos it idle at now?

[leescot]

it is now at between 650 and 700rpm at idle and steady and doesn't fluctuate at all, the only thing is that I can kind of feel (or hearing) like more gas going into the engine at idle. I think it is at the same rpm as before and steady.

[328I99E46]

I do have the same problem 328i 99 e46 been to dealer they said everything is fine i did check codes(none) !! idle is about 700 rpm when i change gears from p to n or d idle will jump up and down also when its in idle and i hit window switch ( when windows are up ) idle will go up and down too not too much but sometimes i think its close to stall its reallly gettting me pissseeddd !! i have no idea what to do next also i can see when i put my ac on radio high beam it will do the same thing i checked my battery and its 12.5 v and with engine running about 14.6 v anyone cane help ???

[PhilH]

Have a quick read of this thread:
http://www.bimmerwerkz.com/forum/3-s...ems-52883.html

[FarhadBimmer]

Hey Phill,

Good info you've put in your thread. Question for you, when you had that problem, were you burning a lot of gas as well?

[zisco]

Maybe Your Electrical Have Damaged.