Idle problem, Need help to solve

[peak08]

 Hi guys, hope someone can help me here,

The car is my track project, it was running great since I bought it.
I didn't use for 1 week or maybe 2. I started it and the idle was really bad!

The idle was so bad, the engine was stalling by itself when we don't give it gas. So I cleaned the ICV and changed the two vacuum hoses connected to it because there was leaks.

Now the idle is kinda stable, but the engine still doesn't run great. It seems to run rich because the smoke is a bit dark.
I have NO checkengine light on.

I have 3 hypothesis :
1)Injectors
2)Knock sensors
3)Throttle Position Switch

What do you think guys?

Thanks for the help !

[keflaman]

First, welcome to the 'club.

Second, we'll need more information about your car, i.e. year, model, market.

The typical M42 we're familiar with doesn't have knock sensors.

[peak08]

Well I though there was knocksensors because people on other forums had checkengine codes for the #1 or #2 knocksensor.

My car is an e36 318is 1994, from the USA

[SkidMark]

Did you do a stomp test? You say you have no check engine light on, but are there any stored codes? Does the idle change when hot or cold? Need a little more info.....Skid

[Tgoode318]

Welcome to the forum. The E36 m42 Does have knock sensors But the early E30 does not.  Even if you cleaned your ICV The plunger inside could still be stuck or broken, Access your ICV unit again and turn your key to the on position and then feel the ICV. The ICV should make a faint buzz when operating correctly. If the icv is bad it can act like a dead mans switch requiring you to give it gas to keep it from stalling out. Since you already replaced one hose you probably have more that are cracked. The easiest way to check for unmetered air entering the engine via these cracks is to spray carb cleaner or brake cleaner in your engine and listen for a surge in idle. Find where its coming from and then replace the hoses accordingly. Also as skidmark said do a stomp Test and see what codes are stored. Hope this helps you out.
-Tgoode318

[peak08]

I didn't do any stomp test because I don't have any reader... :/
And yesterday I did the test for more vacuum leaks with the brake cleaner and I didn't find any

To help you, I have two videos. One before replacing the hoses, so when the problem came on, and the other is after
I replaced the two hoses, which is how it runs right now.

Before : https://www.youtube.com/watch?v=vokKpJLwCkA

After : https://www.youtube.com/watch?v=rm9U765nk04

Thanks again guys !

[peak08]

I looked at my spark plugs, they were all 4 black.

So I replaced them, absolutely no change...

[Gabs]

If you believe it is running abnormally rich, I'd go ahead and change out your oxygen sensor. Your vehicle in part determines the fuel intake requirements via readings from your oxygen sensor. Now I've had vehicles run rich because of bad o2 sensors but I cant say I've had idle problems as a result but its entirely possible.

Now if your a little unorthodox like me, and you don't mind burning a little extra fuel, being that this is a track car, you can delete the idle control valve and set a static idle via the throttle cable. That's how I run mine, I don't know if this has any negative impact on the engine, but none that I've noticed.

Disclaimer though: This will of course throw a check engine light permanently, furthermore when you truly do need to "check your engine" you'll have to rely on a different warning system.