Idling issue

[ctr-]

Firstly the usual process of starting my EP3 first thing in the morning goes like this; the car revs at about 2k and then gradually comes down to under 1k as the engine warms up and then I drive off...

However recently, on cold start, the car would rev at 1500 rpm initially and then about 5 minutes later it would go up to 2000rpm on its own. and as the engine warms up the revs come down slowly but they fluctuate as they come down. After about 15 minutes of waiting for it to finally settle at just under 1000rpm, it stays normal for a little while. But then after a couple of minutes of driving it starts idling a little rough, going from 800 up to 1100 and then staying still for a short period and repeating itself.

Would it be just a matter of taking the throttle body off and giving the idle control valve a good clean?

 

[Bonito]

Whip the idle control valve out and give it a clean with some cotton buds and WD40. Split it down completely to the small butterfly valve. This gets gunked up and stuck and is what causes the erratic idling. There's security torx bits holding it to the throttle body.

 

[ctr-]

Thanks for the reply, I will get onto that tomorrow.

I was just a bit confused as to why the valve would get gunked up, because I have been driving the car regularly (rough and smooth). Its not like the car has been sitting for a long time.

 

[Loxy]

There is a breather from the top of the rocker cover into the intake pipe, it serves it's purpose in venting expanded air from the cam cover but it can throw oil into the inlet.

Most of the time it's fine doing this as it's a tiny amount normally and in driving the car it gets sucked into the engine but over time it can also cause the ICV to get gunked up.

As Bonito said, just whip it off and give it a spruce up.

 

[Bonito]

You'll see when you take it apart. When I did mine, I drove it handy down the motorway. When coming off the slip road and stopped at the lights it started "hunting" again. Back down the motorway and red lined it up a few gears and back off the motorway. All sorted.

 

[ctr-]

This throttle body is super glued on!

 

[Bonito]

As in it was opened before? Art knife or stanley blade and take your time cutting it out

 

[ctr-]

Nope as in it was stuck to the inlet manifold. Anyway after a lot of smacking it finally came off. However I'm going to need a new purge control solenoid. I didn't want to take the pipe off at first because I felt as if it would snap the plastic bit. So I tried undoing the screws, they were too tight. I then decided I will take the pipe off but as I feared, I managed to snap the plastic part. That's the first problem...

I've taken the entire throttle body off and I've tried to take the idle control valve bit off, but one of the screws is stuck solid. I've tried an impact drive, no luck. I've tried tapping it with a screw driver to crack the thread, no luck. So I tried with pliers and now I think the screw may have broken.

 

[ctr-]

The car is sorted now. Had to put a new purge control solenoid in. Couldn't get the idle control valve off, so I just blasted carburettor cleaner through the little hole and the blew air through the thing, it seemed to do the trick. Still ever so slightly fluctuating, but that's to be expected as I didn't take the entire thing apart and cleaned it. Will be doing the valve clearances as soon as I get some time and switch to 0w30 oil for the winter.