wierd idling when cold in 3sgte

[ihavelift]

I did a quick search and couldn't really find exactly what I was looking for so thought I'd start a threat in the hope somebody could shine a light on a little problem I have.

Just changed the spark plugs and inner + outer rocker cover gasket in my st205 and since then it has been idling a bit funny, but only when cold.

It sits at around 2000rpm when I first start it up then as it warms up it fluctuates between 1100 and 1500 I guess, the boost guage showing vacuum fluctuations between -0.8 and -0.5 (all -ish). Once warm though it's all sweet and idles normally.

Any body else had this problem? I'm guessing it may have something to do with the aux air valve in the throttle body?

[sergei]

Is your PCV valve sealed properly?
You could spray carb cleaner into the ISCV if you believe it is binding up.

[ihavelift]

I'm sorry I have no idea what you just said to me haha

[sergei]

There is a valve sticking out on rocker cover next to oil filler cap (sometimes called 710). Check if that valve (grey colour) is sitting in properly.

The ISCV stand for Idle Speed Control Valve. It is on the throttle body (right under it, it will have coolant hoses coming to and from it, as well as larger air hose), you can try and clean it with carb cleaner spray (spray into it, from the throttle side and from the air hose inlet).

[touge_ae101]

PCV valve = positive crankcase ventilation valve. (the one on top of the cam cover normally)
ISCV = Idle speed control valve

if PCV isn't sealed properly it will be causing a vacuum leak (PCV goes into manifold).
ISCV controls the speed which the engine idles at. quite common to block up and can be cleaned with abovementioned carb/throttle cleaner.

i would think it is more likely you have put it back together with the PCV not sealed properly or a vacuum line off somewhere.

EDIT: damn you beat me to it sergei!

[Akane]

Oh yeah I'm having the same problem, except that I can't find the mystery leak and it would fix itself sometimes, and now it's totally fuct after some "spirited driving" sessions.

I already changed to a new throttle body incl ISC valve and checked PCV valve next to the 710 filler, no fix.

[CelicaGT8]

air leak, cold idle pluged in, wiring ok, pipes all hooked up?

[ihavelift]

hmm not doing it this morning.

random.

[sergei]

hmm not doing it this morning.

random.

Did you disconnect battery when you did the cover/plugs?

[Akane]

OK I got up nice and early today and found out my mysterous leak that has plagued me for the last 3 months.

My manifold was falling off LOL!

held on by 4 loose bolts no wonder why it auto accelerates when the TPS is not at idle position roflmao!

Danger to manifold for real. I feel like a badass fast & furious now.

[sergei]

OK I got up nice and early today and found out my mysterous leak that has plagued me for the last 3 months.

My manifold was falling off LOL!

held on by 4 loose bolts no wonder why it auto accelerates when the TPS is not at idle position roflmao!

Danger to manifold for real. I feel like a badass fast & furious now.

[Akane]

LOL sergei.

And I can actually hear backfires from the intake from time to time while idle, so the whole blow your floor off thing might actually be possible!