Gen IV Catch Can?

GTS-R 001

Enthusiast
Joined
Jul 16, 2002
Posts
3,494
Reaction score
0
Location
California (north)
Are any of you Gen4 guys experiencing a funky idle after plugging that port on the intake?

I attempted to install a system like this but taking away the metered vacuum leak by capping off the port on the intake makes my idle hunt. So I installed an oil separator inline with the PCV instead.

Keith,

Try one like this, you can hook the engine up to the -8 and the intake to the -12, I'm just releasing this setup as a plug and play for the Gen 3 but it is easy to make it fit a Gen 4





 

Nine Ball

Enthusiast
Joined
Aug 30, 2007
Posts
3,411
Reaction score
10
Location
Houston, TX
I do notice some oil accumulation in the air intake hose/throttle body area, and some minor smoke out the exhaust on decel/shifing. But it doesn't seem so excessive that I'm freaking out about it.

Allan, it takes very little oil to cause detonation in an engine combustion cycle. Reduced timing can kill 20-30 hp on engines making this much power. You may not ever feel the difference, but track times would show it.
 

Viper X

Former VCA National President
VCA Officer
Joined
May 1, 2004
Posts
3,471
Reaction score
2
Are any of you Gen4 guys experiencing a funky idle after plugging that port on the intake?

I attempted to install a system like this but taking away the metered vacuum leak by capping off the port on the intake makes my idle hunt. So I installed an oil separator inline with the PCV instead.


No issues after 14, 000 miles. Don't see how that could affect your idle unless you have another minor problem, likely a sensor. MAP or TPS sensors come to mind.

I'd see what Mark J has to say.

Dan
 
Joined
Jun 8, 2005
Posts
4,969
Reaction score
0
Location
Omaha NE.
I agree, it could be a contaminated idle air sensor or even a vacuum leak, I have always been told though that you want some vacuum on the vent to help extract the fumes so I always did it that way. Not a big deal for a track only car or drag racer, but cars on the street could benefit in the long run from having some pull through.

JMHO though, there are a lot of smart guys here that feel different.
 

Viperless

Enthusiast
Joined
Oct 28, 2006
Posts
1,367
Reaction score
2
Location
MN
PCV is a huge vacuum leak at idle so the ECM is calibrated to account for it. If you plug it, the ECM is seeing more airflow through the MAF sensors at idle. Why my ECM can't seem to hand that, who knows. All I know is it makes the idle hunt which means the ECM is trying to overcompensate for something at idle. I also can not remove the deflector on my hood or the car goes into limp mode. Others have no problem doing this. I guess my car is just overly sensitive. :D
 

Viper X

Former VCA National President
VCA Officer
Joined
May 1, 2004
Posts
3,471
Reaction score
2
PCV is a huge vacuum leak at idle so the ECM is calibrated to account for it. If you plug it, the ECM is seeing more airflow through the MAF sensors at idle. Why my ECM can't seem to hand that, who knows. All I know is it makes the idle hunt which means the ECM is trying to overcompensate for something at idle. I also can not remove the deflector on my hood or the car goes into limp mode. Others have no problem doing this. I guess my car is just overly sensitive. :D

You many want to have your computer re-flashed.
 
Top