High idle after installing idle control valve!!

stlth15 · Post by **stlth15** » Fri Dec 20, 2013 6:58 am

Hi guys, well I managed to track down an idle control valve after getting jack of no cold idle.

I cut down the log and sealed both ends with plumbing caps, the air regulator and ICV are installed. All original electrical connections reconnected to air regulator and ICV. The plumb back hose, back to the intake manifold after the throttle body connected as well. I also have run a hose back to the intercooler ie: which is the intake after the airflow meter and before the throttle body.

When I start the car, the idle sits at 1500 RPM!! That is after I adjust the top idle screw all the way in. Even after the engine has warmed up. When I screw out, the idle goes higher. It won't drop below this idle figure. Have checked lines, there are no air leaks. Have I plumbed in the connections correctly. I couldn't put log in original location due to my intercooler piping being in the way.

Here is a Youtube vid

Damo · Post by **Damo** » Fri Dec 20, 2013 11:09 pm

You will have to adjust your throttle blade. With the engine fully warmed up, screw out the high speed engine idle screw around 3 to 4 full turns, then adjust the throttle stop screw on the T/B to lower your warmed idle speed. Make sure all your ignition timing, throttle switch and valve clearances are set correctly before you start, or you will end up chasing your tail!

Damo

stlth15 · Post by **stlth15** » Sat Dec 21, 2013 7:32 am

Thanks Damo. I sorted the issue thinking about the comments I've read about the AFM relocation. The breather hose from the Rocker cover had not been tapped in after the the AFM relocation. It was still before the turbo and AFM!

This has now lead to a very bad mistake on my part.

The breather hose from the rocker cover (drivers side) I tapped in to the log. Idle worked perfectly and then took for a test drive. After the test drive I'd come back to find I had a massive oil leak and the engine bay was covered in oil! The Dipstick had popped up thinking that was the culprit. Then after further investigation, found the 17mm oil hose under the turbo leading back to the engine had split. Luckily tracked down some spare OIL hose from an industrial wholesaler at 5pm on a Friday afternoon! After fixing this and degreasing, went for another test run to find that oil is now pissing out of the rocker cover gasket!!

Such an amateur move LOL, did some research again last night and came across posts about a PCV valve which now makes sense. So I'm assuming I have to stick a PCV valve in the breather line when I tapped in to the log. Reason being, turbo air is pressurising not only the log but now my rocker cover causing the rocker cover leak?

Is this right?

Post by **tassuperkart** » Sat Dec 21, 2013 2:42 pm

So your blowing thru whats left of the log?

You need to just make sure that ANY additional air that makes its way into the engine MUST be metered air. From DOWNSTREAM of the afm.

One side of the rocker cover should be drawn from between the AFM and the turbo.

The other side should dump into the manifold on the other side of the throttle body via a PCV valve.

PCV system needs to see both boost pressure and vacuum or it wont work.
The PCV valve acts as a checkvalve when the manifold is pressurised but passes air INTO the manifold (from the rocker cover) when under vacuum.

Im still not clear on how you have you system plumbed with the likes of hoses running to intermahcoolers and elsewhere so draw a diagramme or take pix.

Oracle

stlth15 · Post by **stlth15** » Sat Dec 21, 2013 8:06 pm

Sorry for the dodgy youtube video

Hope it makes sense. So my question is, can I stick a second PCV valve between the Rocker cover (drivers side) and the intake into the throttle body. This is what I'm hoping will stop the boost pressure forcing oil out of the rocker cover??

If this cant be done, then I will have to relocate the AF meter before the turbo and retap the breather line between the AF and turbo. As you can see my AFM is after the Turbo, which I think is my problem?

Cheers Guys

Damo · Post by **Damo** » Sat Dec 21, 2013 11:20 pm

O.K, I haven't looked at your vid, but i am quite sure (as you are) you have a plumbing issue. Having the engine breathers set up the way you have is going to result in pressurizing the sump and blowing oil out of anywhere it can go! I would count yourself lucky you haven't blown the sump gasket.

If you have both breathers plumbed into the manifold after the TB, anytime you are on boost you will pressurize the sump. First, forcing oil out of the dipstick, then blowing the weakest hose (which is usually the oil drain) then forcing oil past the oil seals on both sides of the turbo and the valve stem seals. You may find you have dumped a couple of hundred ml of oil straight into your exhaust which will smoke like a mofo for 10 - 50ks (like mine did

) until the stuff burns off.
The drivers side oil vent mustn't have a check valve and must be plumbed pre turbo and post AFM! You can't vent to atmosphere as the ECU wont get the correct mass airflow from the AFM, and you can't plumb to hot side of the turbo, as sump pressure must be below inlet pressure!

Make sure you get that last paragraph clear in your head or on paper as it is essential.

Right, I have just checked out your vid. If your system is set up that way, change it! You can't get the venting system to work correctly if you are blowing through your AFM. I can't for the life of me understand the rational of blowing through the AFM, boggles my mind.

Damo

stlth15 · Post by **stlth15** » Sun Dec 22, 2013 6:07 am

Thanks Damo, makes sense, what you say. Can you or someone explain to me the theory for the 2 breather lines, from the rocker cover. Is the drivers side breather an inlet and the passenger side with PCV valve the outlet?

Cheers for the pressure plumbing lesson

Post by **tassuperkart** » Sun Dec 22, 2013 8:08 am

See my post above.

Oracle

stlth15 · Post by **stlth15** » Sun Dec 22, 2013 9:18 am

Ahh cheers

Post by **tassuperkart** » Sun Dec 22, 2013 2:57 pm

Ahhh I see whats happening now. Looked at the vid I didnt notice before.

Mmmm blowing thru AFM's..... Its been done but its a mod for mods sake and creates its own set of issues to get around.

Nope, you cant have any operating PCV system with things plumbed up that way. Your always going to pressurise the crankcase even with 2 pcv's in place.
Youll have to have the vents from the rocker cover, preferrably via a catch can coming back to between the airfilter and the turbo.

Dump it to atmosphere for ghetto approach but thats just a little naughty!!!

Oracle.

stlth15 · Post by **stlth15** » Sun Dec 22, 2013 8:06 pm

Yeah which comes back to my original issue of high idle

. I think my only way getting round this issue is move the afm between air filter and turbo. Then plumb the rocker cover breather hose after the afm and before the turbo. Just hope I haven't blown the sump or rocker cover gaskets!!!
Cheers guys for the info

Post by **tassuperkart** » Mon Dec 23, 2013 8:37 am

Oh, youll have to wait and see on that one.
The connection is;
Airfilter > AFM > Idle Valves > Turbo > Intercooler > TB/Plenum/manifold.

Drivers side Rocker cover vent plumbs between AFM and turbo

Passengers side Rocker cover vent plumbs to plenum via a PCV valve. PCV to allow air INTO plenum NOT out.

Enjoy!!!

Oracle