What's this in my plenum?
 

Hey guys, I just finished changing plugs, wires, and valve cover gaskets on my 06 GXP. I noticed when I took the cover off the plenum there is a port in the middle of the plenum. I'm not sure if something goes here and if it's sucking air when the car is running because I have the battery out of it from doing several things. If something goes there I figure it can't be much since the cover sits on top pretty close. Not sure if this is the original plenum since I bought it used. Any info on this? I looked for pics of an LS4 plenum but had no luck.

There is an unused nipple on the manifold. I'm assuming that's what you're talking about.

There is an unused port on mine right near the TB, not sure if that is what you are talking about. A pic would help?

Ok. I'll get a pic when I get home. Not really sure how to post it since I've never had to do it.

https://cimg2.ibsrv.net/gimg/ls1tech...e533194eaa.jpg


https://cimg3.ibsrv.net/gimg/ls1tech...3dfc2e1d54.jpg

thats the map sensor port, and the one to the right of that comes off the back valve cover with a vac hose

map sensor

Since your a 06 you just need to move the map over to that location since it used to sit by the throttle body for all 05 06 ls4 vehicles

So is he missing it ?

91parkave is my map located somewhere else. I haven't noticed a wiring harness for it in that area in the picture.

one of the MAP ports should be blocked off depending on the year, you can just test that by using a small screwdriver to see if it goes into the manifold. If both ports are open, then you need to block one of them off so it cant put air through it. Although they shouldnt be.

Ok. I'll check it out. Thanks for the help.

I've never seen a ls4 manifold with both locations for the map odd.

Where do I need to look for my MAP sensor? Near my throttle body?

Just leave it where it's at and plug the other port

How long have you owned this car and is it throwing any codes or running rough? Seems odd that would be moved and also the vacuum line unhooked unless you did that?

I took the vacuum line off when I was changing valve cover gaskets, plugs and wires. I got it in March and drove it home about 250 miles and did not have any codes to come up.

I guess just look around and locate the map sensor, it has to be somewhere . Has to have a harness for it in that general area?

Looks like the map is on the R/S of the pic.

I just checked and it's right behind the throttle body.