M42 idle issue. help!

[iamcreepingdeath]

(I posted this a long time ago, and i still have this problem.)

Anyway, after the last autocross meet, my car developed a funny idle.  When i start the car cold, it idles super rough and low like it has some wicked cams, and then stalls out.  After the car warms up, it idles fine, but a bit high at 1000 rpms, which i figure i can fix by just adjusting the idle.

I did some forum searching, and it seems the cure-all is to clean the ICV.  Now please forgive my ignorance, but where is the ICV valve, and to clean it do i just kill it with some brake cleaner?

I already fixed two vacuum hose issues and no change in the idle problem.

Second question of curiosity is as i was taking the intake boot apart to find vacuum leaks, i discovered a whole LOT of grime buildup on the inside of the boot and in the throttle body.  Its like a dirt and oil mix, not goopy or wet, just dryish and caked.  What in the world would be causing this?

Thank you guys so much for your help.

-SAm

[DesktopDave]

The ICV is mounted below the rear of the intake manifold, close to the firewall.  On the e30 it sits on a vac pipe that connects to the rear of the upper intake.

Clean it with TB or carb cleaner, no immersion.

All of us with vac leaks have gunk built up all over the place.  I'm told that it's due to dino oil and leaks building up all that grime.  The intake pulls oil back and mixes with air from vac leaks, causing that crud to build up.  I'd figure all three are related.  You might want to consider the 'vacuum hose delete' mod detailed on this board in many threads.

[Frank Gallegos]

Sam,
The ICU is located just to the right of your intake manifold, as you stand on the drivers side of the engine, and is tucked in a little.  You should have little trouble getting it off and out to clean.  Get yourself some good carb cleaner and flush it out and let dry.  Site will not let me post my pics of mine but there is a pic of it in the following thread.

The gunk you are asking about is commonly found in all of our cars.  Here is a post that addresses it and an idea on how to try and remedy the issue of its build up. ( there is also reference to the ICU in this post so look for some more pics of it in the post as you read through it )

http://www.m42club.com/forums/showthread.php?t=2742&highlight=Reservoir

[iamcreepingdeath]

thanks so much guys.

A vac hose delete??  how is that possible?  i guess a little more searching is in order....

[iamcreepingdeath]

just glanced through the above linked thread, that is definitely something i am going to do!

[iamcreepingdeath]

NOW WHAT??

So i cleaned my ICV, found tons of cracked hoses and because of a time and money limitations i fixed them with hose clamps and liquid gasket, and got the ol' M42 back into service.  

NOW, when i start the car COLD, the idle is super low and the motor stalls right away.  To keep it alive i have to keep revving it, and then quickly jump into the engine bay and adjust the idle to keep the engine running.

Then after i drive the car and it gets warm, the idle becomes higher, and so then i go back into the engine bay and lower the idle back down to normal.

If i let the car cool for several hours and then restart the car, super low idle again and instant stall-out without revving the engine.

WTF is up with this???  should i go ahead and do the vacuum hose delete mod? do you think this will solve it?  Thanks so much guys!!!

[Frank Gallegos]

My next move would be to try and revisit that ICV and give it a closer look again.  I will look into and see if there is anything else you could be looking for or doing.

Frank

[91 318is]

I've been having the same problem, idle wise with me mine for a little bit.  Only thing I did was use some of my old vacuum hose that didn't look cracked for the delete mod.  I plan on just changing it ALL so I know it's new.  But when mine's cold, it idles normal, as it warms, rises up to about 1200.  

See what it does when you turn the A/C on, does the idle drop back down to about normal?  I know when mine's fully warm and idling at 1200, if I turn the A/C on, it drops down to normal idle at 850.

[iamcreepingdeath]

My next move would be to try and revisit that ICV and give it a closer look again.  I will look into and see if there is anything else you could be looking for or doing.

Frank

what would i do ro revisit the ICV?  i just sprayed in ALOT of brake cleaner and WD-40 to re-lubricate it.  Is this bad?  can i actually take the ICV apart?

I've been having the same problem, idle wise with me mine for a little bit.  Only thing I did was use some of my old vacuum hose that didn't look cracked for the delete mod.  I plan on just changing it ALL so I know it's new.  But when mine's cold, it idles normal, as it warms, rises up to about 1200.  

See what it does when you turn the A/C on, does the idle drop back down to about normal?  I know when mine's fully warm and idling at 1200, if I turn the A/C on, it drops down to normal idle at 850.

my AC doesn't work.  Its not even hooked up.

[iamcreepingdeath]

EDIT: So anyway i did the vacuum hose delete mod successfully.

[iamcreepingdeath]

No vacuum leaks, i did the delete, and cleaned all the gunk.

BUT, my car will stall out at an idle when cold, and when warm, it idles fine on the high side.  Do i need a new ICV?

[iamcreepingdeath]

bumpity bump bump

My car will barely run when cold, i have to hold the revs with the throttle to keep it running until it warms up.  What can be the problem???

[B318M42W]

for some odd reason i'd look at the FPR... remove the tiny vacuum hose and see what happens. by removing it, you are causing a rich fuel situation. if you can find something that can create a small vacuum and plug it on there, it will cause a lean situation. If one out your injectors is leaking, you'de have too much fuel for the amount of air and that could cause rough idle/ stall.

[iamcreepingdeath]

but it only happens when the car is cold, and much worse in colder weather when the car is cold.

[B318M42W]

i'm guessing that if your O2 sensor can't see the extra fuel, the ECU will just dump some more in... just a thought