Mystery vacuum nipple?

[Turbo_smh]

So I have my LS1 up and running however, I have this vacuum nipple on the right side of the front part of the intake manifold http://www.ls1truck.com/upload/files/251/IMG_4111.JPG

Its the one on the upper left with the silicon around it. From what I understand Its for the evac system which i think i had eliminated with the tune. If I uncap it the truck runs fine, if I cap it it the truck tends to die out and idles too low to run the ac and also when the truck shifts out of park to rev and drive etc. I know it needs to be either capped or routed to something. Any Ideas?

[GasGuzzler]

Is that a 5.7 when a car intake? What I see in the picture is on the left side of the engine (driver's side is always LH). On a truck, that's not there, it's on top....and is for the EVAP system purge valve. It should be capped if the EVAP has been eliminated.

Is it possible the idle, etc. in the tune was set with that port open?

[Turbo_smh]

Is that a 5.7 when a car intake? What I see in the picture is on the left side of the engine (driver's side is always LH). On a truck, that's not there, it's on top....and is for the EVAP system purge valve. It should be capped if the EVAP has been eliminated.

Is it possible the idle, etc. in the tune was set with that port open?

Yea the motor is actually out of an 02 camaro and the tune is from pcmforless. At the moment im installing new heads and weiand intake. I guess ill make a note to whoever tunes it next about the evac issue. Thanks for the info

[George C]

Yea the motor is actually out of an 02 camaro and the tune is from pcmforless. At the moment im installing new heads and weiand intake. I guess ill make a note to whoever tunes it next about the evac issue. Thanks for the info

that should be capped off. if you have a 02 motor then the intake you have is the ls6 unless someone swaped it on you. the wieand intake is junk compared to the ls6.

capping it and it bogging down is in tune or setscrew on TB

find another tuner PCM4less couldnt tune a lawnmower

[Jamest]

it needs a retune and it needs to be capped. The tune is tuned with the extra are thru the silicone port. When capped it is not given the amount of are to idle?

[Turbo_smh]

it needs a retune and it needs to be capped. The tune is tuned with the extra are thru the silicone port. When capped it is not given the amount of are to idle?

You are correct sir, it does idle but any throttle change and the truck tends to die out. Leaving it open helps the problem but doesnt fix it of course. Im probably headed up to SA today and am gonna stop by Nelson for my first time to talk about a tune.