Boucing idle on the eS

[Jand3rson]

My 325eS has been having a bit of an idle issue for a few months now, I thought maybe you guys could give me a few things to look for. Once the car is warmed up, the idle starts to regularly flucuate between about 500-800, give or take. It's not as vigorous as say, when the ICV dies (had that happen on my old 325i, that was a LOT more up and down). This is just a small flucuation, but it's annoying, and I'd like to fix it. I hope I don't have to replace the ICV, them are spendy!

I know a few things to check are the intake boot (for cracks, I have a new one from the parts car, just need to put it on), but I'm wondering what other things I should check that might be giving me this idle problem. I've owned the car since February of '05, and since then, I haven't given it a proper tune-up (plugs, cap/rotor, etc) which I know I need to do, so could that maybe be part of the problem? It's also been suggested that I check the O2 sensor. Could someone refresh my memory on how to do the stomp test?

Thanks in advance. :D

[AndrewBird]

I would first do the plugs. If you've never done them, they are in for a changing. Also check the cap and rotor and see how they are. If not bad, just clean the contacts off with some sandpaper and reinstall. If there is a lot of corosion, I would just replace them both. Check your air cleaner too. If it's not been changed in a LONG time, that could be giving you problems. All of it combined together could be the problem.

[MitchFong]

I got the same problem. Well mine has been in storage. But there has been no snow, so every couple weeks i take it for a drive, car takes a bit to warm up, but even when its warmed up, the first half hour of driving it will shut off at a red light. I have to give it a bit of gas. But after that, it drives perfectly fine?? I think my plugs need a change to tho. Wouldnt even know when they were done last.

[nando]

josh your car is motronic 1.1 I believe, so the stomp test probably won't tell you much of anything.

[Jand3rson]

I would first do the plugs. If you've never done them, they are in for a changing. Also check the cap and rotor and see how they are. If not bad, just clean the contacts off with some sandpaper and reinstall. If there is a lot of corosion, I would just replace them both. Check your air cleaner too. If it's not been changed in a LONG time, that could be giving you problems. All of it combined together could be the problem.

Plugs and all that good stuff are definitely on my list of things to do soon, once we get a warm weekend. As far as the air filter, I've got that pretty much new K&N panel filter from the parts car, I just need to get off my ass and go buy the cleaning kit so I can put it in. There's just a Fram in there right now. I know, I know... but it was all they had, and I didn't have the cash on me for the K&N, and the one that was in there was NASTY!

[BMW BMXER]

My car used to do this a lot. I cleaned out the icv with xylene and it went away, but would come back every few months. Evenutally after getting the JC and switching fuel it went away.

Odd.

[chuckybob]

my 318i had a variety of the symptoms above. loosening the idle control valve adjusting screw solved it.

[cunninglinguist]

Start here:

http://www.mesaperformance.com/faqs/idle.html

[EtaSport]

The above link never finds a solution to the problem. This is one problem that I used to have, and I really dont know where it comes from. The only thing I never messed with was the ICM near the ecu in the glovebox. Things you can check are:

coolant temp sensor (the yellow top sensor, should have two prongs)
the ICV (perhaps clean, although some dont recommend)
the ICM (only thing you can really do is replace it)
throttle plate sticking, causing tps not to rest in idle position
o2 sensor is possible, but if the o2 sensor was not operating the car would remain in open loop mode.

Only other possibility is a small vacuum leak, if you can check your vacuum at idle. I think my car's got a small leak as it has low idle vacuum.