Vac Line [Archive] - GrandAmGT.com Forum

PDA

View Full Version : Vac Line


jd99gagt
05-15-2012, 03:40 PM
I have a whistle when my engine is running, and when I plug the end of it with my finger the whistle seems to stop, I can't see anywhere that it would go. It's the line coming out of the front valve cover. Also if anybody has the order in which the spark plugs wires go that would be excellent.

AaronGTR
05-15-2012, 03:56 PM
Uh, yeah.... the plastic line coming from the front valve cover with the silver thing in the rubber grommet? That is the PCV valve, and that line is supposed to be going to the top of the intake manifold behind the throttle body, and also connects to the EVAP solenoid on the other side of the throttle body. If that's not connected you will have a major vacuum leak. That has to be under vacuum to draw air through the PCV system and evacuate the crank case and through the EVAP system to purge the charcoal canister of gasoline fumes from the fuel tank.

Spark plug wires should be numbered if they are stock ones. Looking at the engine from the front, they go 1-3-5 across the back and 2-4-6 across the front, from left to right. In fact, I believe I just answered this same question in this section a couple days ago. ;)

jd99gagt
05-15-2012, 06:47 PM
Uh, yeah.... the plastic line coming from the front valve cover with the silver thing in the rubber grommet? That is the PCV valve, and that line is supposed to be going to the top of the intake manifold behind the throttle body, and also connects to the EVAP solenoid on the other side of the throttle body. If that's not connected you will have a major vacuum leak. That has to be under vacuum to draw air through the PCV system and evacuate the crank case and through the EVAP system to purge the charcoal canister of gasoline fumes from the fuel tank.

Spark plug wires should be numbered if they are stock ones. Looking at the engine from the front, they go 1-3-5 across the back and 2-4-6 across the front, from left to right. In fact, I believe I just answered this same question in this section a couple days ago. ;)
Thanks, I found it. It's kind of below the coil pack behind the engine. It Idles real nice and smooth now.:)

AaronGTR
05-15-2012, 08:33 PM
Thanks, I found it. It's kind of below the coil pack behind the engine. It Idles real nice and smooth now.:)

That is the inlet for the PCV system. That is supposed to have a plastic line in it running to the intake tube behind the MAF sensor. It is where the fresh air comes from that gets pulled through the PCV valve on the front cover. That line often doesn't like to stay in place. If that one pops out you won't have a vacuum leak, but you will be pulling un-metered air into the engine and it will throw off your fuel trim.

jd99gagt
05-16-2012, 02:23 PM
I heard the same whistle again and the rubber end that is on the end of that pcv hose is cracked on both ends. I tried taping it up with electrical tape as a temp but it's probably still leaking through the cracks on the vertical ends. there are no other vac lines that could be leaking behind the engine that I'm missing right?

AaronGTR
05-16-2012, 04:15 PM
There is a small vacuum line that comes off the back of the manifold. It goes under the MAP sensor and connects to it on the bottom, then goes around front and hooks to the fuel pressure regulator. There is also the big rubber hose that goes to the brake vacuum booster on the firewall.

If the rubber boot on the PCV is cracked, that's probably where it's coming from though. Not uncommon with those boots, once the rubber gets old. You should be able to find a replacement at the auto parts store. The old one should pull straight off the plastic line.

jd99gagt
05-16-2012, 04:36 PM
Both of those lines are connected, it has to be the pcv one. I took off the coil pack because I thought I might have slacked on one of the valve cover bolts so I tightened it a little more but after I tightened it came to me that a valve cover leak probably wouldn't make a sucking noise and just leak oil. So i started it without mounting the coil pack and when i would move the coil pack up and down it would move the pcv inlet where it was attached and it would start then stop continuously as I moved it up and down so it must be it.