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using a skunk 2 throttle body that has working tps and working map , no sticking butterfly or tight throttle cable and throttle screw is screwed all the way in.

using a skunk 2 intake manifold with brand new Honda OEM gasket

used IACV that works , doesn’t surge and doesn’t have any different affect unplugged or plugged in. About the same rpm regardless
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my problem is their is CLEARLY a vaccum leak but trying to find out where is the hard part. I sprayed break clean all around the intake manifold , throttle body , and all my vaccum hoses and no increase in idle.

however when I cover my throttle body with my hand it drops rpm’s but doesn’t kill the engine.

further more when I pinch the hose going from the valve cover to the Intake manifold it decreases rpm’s until I pinch it more then finally dies. Putting those cheap autozone cone / breather filters on both ends doesn’t work other.

im slightly confused on what else to do here. Any and all advice is appreciated but I think I’ve covered all the basics / common sense things. It’s clearly a vaccum leak but where!

it does this when car is cold or warm , doesn’t really matter , coolant is also fully bled. I also tried a different IACV and same thing so I put the known working one back on

 

Can you post a picture of the hose between the intake manifold and the valve cover ? If I understand what you have done here correctly, this creates an internal vacuum leak and is the cause of your high idle and/or hunting idle.

The port on the front of the intake manifold plenum normally goes to a PCV valve, which is mounted into an oil separator box that limits the internal crankcase ventilation. Since the B20B/Z block does not have an oil separator box, a different creative plan must be utilized. If you eliminate this system, you place a vacuum cap over the port on the intake manifold and then slightly adjust the throttle blade open with the throttle stop (then reset the TPS and throttle cable tension) to increase the idle speed. Another common fix is to connect a hose from the intake manifold plenum port that is long enough to reach down through the intake runners or OE style PCV port, install a PCV valve on to the hose below the intake manifold, and place a small breather filter on the PCV valve so that you are drawing clean air through it. This will limit the amount of air that is "leaked" in.

 

thanks for the reply! That’s the hose in question. When I squeeze it brings down the idle / kills the engine if I pinch it hard enough.

if I put a small filter on the valve cover port and cover the intake manifold port with a rubber nipple the engine won’t start.

im not too savvy on adjusting TPS I know the procedure but if theirs another way around it , I’d love to know.

 

can you elaborate more on this?

Another common fix is to connect a hose from the intake manifold plenum port that is long enough to reach down through the intake runners or OE style PCV port, install a PCV valve on to the hose below the intake manifold, and place a small breather filter on the PCV valve so that you are drawing clean air through it. This will limit the amount of air that is "leaked" in.

idk if im stupid but just not quite understanding that. I’m running a skunk 2 pro series intake manifold.

 

sorry I just thought of it

I have a OEM pcv valve , and their is a hole on the manifold made for it ,

so basically what you’re saying is put the hose on the intake manifold top port , put the PCV valve in that hole , and connect that hose to it? Is it that simple?

 

Put the hose on the intake manifold, run the other end of the hose THROUGH the round opening in the intake manifold casting between the #3 and #4 intake runners so that the end of the hose is BELOW the intake runners. Place a PCV valve into the end of the hose. Finally, install a small breather filter over the end of the PCV valve... similar to the one that you talked about installing on the nipple of the valve cover in your photo.

Is this clear enough ?

 

yea sir!!

it fixed my idle!

Im now at a solid 1,000 rpm idle!!

Drops to 700-800 rpm when IACV is unplugged

and now when I cover throttle body the engine dies so that tells me no more vaccum leak

as well as my CEL is gone. Always had one even when I first got the car now it’s gone!

 

Excellent. Congratulations.