What is this part???

[slaterd]

Bought a 1988 325e with a rebuilt head a few weeks ago. My car idles okay but not the best , it still idles kinda rough. Went to a BMW dealership to have them reset maint. lights and pull possible codes. When the tech. looked closer he noticed that something wasn't right. This part in my car is backwards, the two male points of the adapter are switched. When I went home, I switched them and now my car idles like shit and stalls within a couple seconds. What is this part and why doesn't it work correctly when it's put in correctly?
This is the correct position it should be in, mine is running perpindicular to this position.

[Cronopoulos]

Iacv?

[acolella76]

that is your idle control valve (ICV). I would say it's not working. Make sure it buzzes when it's plugged in and the car is in the 'on' position, also take it out and spray some carb cleaner in the ports. When you shake it, it should sort of rattle.

[slaterd]

I checked that, key on engine off. Grabbed it and felt it vibrating so it's working.

[Teaguer]

If its buzzing then yes its working. To be sure though take it off, put a finger over 1 port and fill it up with carb cleaner or brake cleaner then cover up the other port with your thumb and shake the shit out of it.
Do this a couple of times and you can finish it off on the last one by using wd-40 or some other spray lubricant.

Also you can see if unplugging it when running has any effect on the idle.
So what codes was the car showing?
For future reference you can pull codes on an e30 yourself with no tools.

[slaterd]

Yeah I knew that before i went to the shop, but I asked to double check to make sure that was the correct procedure. But my car didn't put out any codes for some reason. ANd are you takin about plugging the ICV or the hoses that it connects to??

[Teaguer]

Remove it completely and hold it in your hand when cleaning/lubing.
Once reinstalled and the car is idling unplug the electrical plug to see if it affects the idle. You can unplug and plug it in several times in a few seconds with car idling.

[scottinAZ]

The picture shows the ICV installed correctly. ensure yours is the same way. Other than that, there are several points that can cause issues. First being the intake boot, they crack over time and dont seal worth shit, intake leaks cause problems. Second point to check is the elbow between the icv and throttle body. again, they dry out, and dont seal, causing leaks, check this as well. Third point is the actual metal elbow that attaches to the throttle body, they arent staked in well, and come loose. again, causing intake vacuum leaks. all will cause problems with idle quality.