Bouncing Idle problem, unanswered at gay bmw-forum

[pogiboy9]

Having bouncing idle problem on cold start

replaced icv
replaced idle module
checked coolant temp sensor

need more ideas or common problems
and maybe solution.

Also heating problem only on idle,

ideas i have
-radiator isn't flowing correctly
-expansion cap (radiator)

things i've done
-checked circulation tempature while running on radiator
and it was cold at the bottom radiator temp plug (sorry forgot the name I'm out of it)
and it was hot, but the top one is about 40 degrees colder... \= help ?

[Erick]

What year is your car?

Could be the O2 sensor ( my case right now )

[Jand3rson]

What year is your car?

Could be the O2 sensor ( my case right now )

I don't think so. The o2 sensor in my car was completely dead (the 88 325) and my idle was just fine. The only time I had an idle problem was when my ICV died outright.

[Jordan]

And I wonder why no one has answered it yet....

You need to tell people what engine you have, what year and model car you have etc. None of us are mindreaders.

[86325e]

Check for vacuum leaks or a torn AFM boot.
Does your ICV feel like its buzzing when you put your hand on it?

[BavarianBimmer]

First of all what type of engine do you have ?

IMO it seems more like waterpump probs or a bad flow, do you've done a flush ?(heating probs on idle)

[elemental]

Checked the little things like, OIL Cap for a vacume leak or anywere else for that matter? I would have to start there if you havnt allready done that.

[RedBaron86325]

bleed the cooling system

[randywalters]

Pull up the fault codes.

[pogiboy9]

Wow.... I'm staying here LOL leaving bmw-forums, seems like only i answer their questions and i leave one or 2 questions and no reply.

Well to whoever said o2 sensor,
-I've replaced it

LOL and for everyone
-'84 325e 2.7L
-lol i could've done the E to I swap but couldn't find a Junk 325i
-i've already resurfaced the cylinder head and port polished :)

Vaccum Leaks
-Thats my next deal
-i've run tests on all the ICV
-Coolant temp sensor
-replaced both ICV and MODULE
-Ordered the radiator expansion cap

Flushing the radiator is my next step,
if not flush just replace it.

[Werksmini]

Ajust the valves? I did it and now the CRAZY idle is gone but it says at like 2000 for a while... dont want to jack your thread but check into that. Maybe a valve cover gasket?

[Saul325is]

My first guess would be ICV, but since you replaced that then your best bet is the O2 sensor, but you replaced that. I HAVE THE SAME PROBLEM, ever since I used an e34 M50 boot (because im running an M30 AFM). Since i rerouted the ICV, ive had a bouncy idle. My guess is a vacuum leak, near the ICV. This is because im running a smaller vacuum hose from the ICV to the TB(so there must be a small leak). What I would do is just check all the hoses and listen for any leaks.

-Saul

[86325e]

I'm still leaning towards a vacuum leak.

However, here is an idle FAQ that I found useful when I was troubleshooting this problem with my 86 eta. At the time I replaced the ICV, ICM module, and all vacuum hoses and still had the problem. I went through this FAQ electricly checking everything with my multimeter and found out that there was a brokem wire in the connector that connects to the ICV (Thats why I asked if you put your hand on it to see if you feel it buzzing). BTW did you replace your ICV and ICM with brand new units or assumed working used units?

On the O2 issue. Does the idle bounce with the car in either closed loop or open loop mode or both?

http://www.geocities.com/bmw535i86/text/idle_FAQ.html

[rs4pro3]

My friend had a bouncing idle on his 86 325, after he replaced the Idle module it smoothed out but not perfect, His o2 sensor was bad so he is going to replace it and see if it will help.

[skat 325is]

I replaced the O2 sensor, ICV, and bought a used AFM and it went away, i think it was a faulty AFM.