Idle slowly creeping up?

[UlrichFennec]

So I took the vert for a drive today for around an hour, and then I got home to notice my idle was going up from the 850-900 to roughly 1100-1200. Veeeery slowly, though.

I popped the hood open and the little hose that goes from the ICV to the intake manifold has cracks at both ends. Could this be the problem? I've already ordered the part anyway cause it needs to be replaced obviously, but would taking the ICV out and cleaning it out help as well?

[UlrichFennec]

Bump?

I've also noticed after warming up for a bit to operating temp, if I'm sitting at idle, the check engine light flashes on and when I drive off it goes away.

[BMWManiac]

Are you able to pull any codes with a stomp test?

Yes, any vacuum line/hoses that are cracked could be letting unmetered air in or out. After you've replaced that hose, does your idle do the same thing?

I'm guessing you still might have a vacuum leak somewhere. First step, eliminate vac leaks by doing a smoke test

[modernist]

Vac leaks yes, but Motronic is really good at regulating idle speed. Mine will idle dead even at 750 rpm even with the brake booster hose disconnected. It will idle like it has a huge cam, but the speed is steady. The ECU sets idle speed according to coolant temperature inputs, a/c status, and automatic transmission position (if applicable). I'd do a stomp test to read any codes first, and cleaning out the ICV with carb cleaner is always a good idea.

[UlrichFennec]

Okay, so the only code it's throwing is 1222, so it isn't an O2 sensor, and now I'm really leaning to vacuum leak. I had already replaced my spark plugs, distributor cap and rotor, fuel filter, and the timing belt and valve adjustment was done recently.

It will idle at cold start like it has a lumpy cam, but other than that, I'm not having any sluggish acceleration, response or other crazy issues. Just a high idle.

[modernist]

1222 is a lambda code, which means there's a problem with air/fuel ratio. Vacuum hoses are cheap, I would just replace all of them.

Also, have you tested the coolant temperature sensor?

[UlrichFennec]

Right-o.

I have not tested the coolant temp sensor. I should do that!

[UlrichFennec]

So we were learning about smoke tests today in class, coincidentally. I volunteered to be the guinea pig, so we hooked the smoke machine up to where the fuel pressure regulator line goes to on the intake manifold.

We found one leak underneath the manifold, but we couldn't pinpoint the source, but my instructor was pointing towards a bolt where the smoke was coming out. He was saying it might be the manifold that was leaking.

Are there any lines underneath the manifold that I should know about that I haven't seen?

[Kershaw]

Perhaps it was leaking from the bitch tube?

[UlrichFennec]

Perhaps it was leaking from the bitch tube?

Funny you mentioned that. After I cleaned the ICV and replaced the hose, I started spraying around to find any other place. Sprayed towards the spring loaded tube of death and BOOM, the idle jumped!

Looks like that's my problem.

[modernist]

Oooh have fun. Guess it's a good chance to do intake manifold gaskets too.

[UlrichFennec]

Alrighty. So I just ordered some fresh manifold gaskets, vacuum lines and oil return tube o-rings. Now we wait.