valve cover to TB tube... whats it actually do?
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From: plano texas
valve cover to TB tube... whats it actually do?
Just like it says what does the crankcase venting to the TB do besides maybe put the crankcase in a vacuum... or is that about it? seems like its pretty useful in that case but other wise... 
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Re: valve cover to TB tube... whats it actually do?
The tube is there to supply fresh air that has been filtered and measured by the MAF sensor, to the valve cover. There is no vacuum on that port. Its connected to a point in front of the throttle blades.
The air that enters the valve cover is pulled through the crankcase and lifter valley by vacuum, via the PCV valve on the driver's side of the intake manifold. The fresh air picks up the water vapor and other blowby that gets by the rings. It all ends up in the intake manifold, where it enters the combustion process.
If engine vacuum is low for an extended period of time (WOT) or if you have excessive blowby that the PCV valve can't handle, the excess pressure in crankcase can force the vapor to flow backwards in the tube, and blow the vapors, and often some entrained oil droplets into the throttle body.
The air that enters the valve cover is pulled through the crankcase and lifter valley by vacuum, via the PCV valve on the driver's side of the intake manifold. The fresh air picks up the water vapor and other blowby that gets by the rings. It all ends up in the intake manifold, where it enters the combustion process.
If engine vacuum is low for an extended period of time (WOT) or if you have excessive blowby that the PCV valve can't handle, the excess pressure in crankcase can force the vapor to flow backwards in the tube, and blow the vapors, and often some entrained oil droplets into the throttle body.
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Joined: Jul 2004
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From: Charleston, SC
Re: valve cover to TB tube... whats it actually do?
Originally Posted by Injuneer
The tube is there to supply fresh air that has been filtered and measured by the MAF sensor, to the valve cover. There is no vacuum on that port. Its connected to a point in front of the throttle blades.
The air that enters the valve cover is pulled through the crankcase and lifter valley by vacuum, via the PCV valve on the driver's side of the intake manifold. The fresh air picks up the water vapor and other blowby that gets by the rings. It all ends up in the intake manifold, where it enters the combustion process.
If engine vacuum is low for an extended period of time (WOT) or if you have excessive blowby that the PCV valve can't handle, the excess pressure in crankcase can force the vapor to flow backwards in the tube, and blow the vapors, and often some entrained oil droplets into the throttle body.
The air that enters the valve cover is pulled through the crankcase and lifter valley by vacuum, via the PCV valve on the driver's side of the intake manifold. The fresh air picks up the water vapor and other blowby that gets by the rings. It all ends up in the intake manifold, where it enters the combustion process.
If engine vacuum is low for an extended period of time (WOT) or if you have excessive blowby that the PCV valve can't handle, the excess pressure in crankcase can force the vapor to flow backwards in the tube, and blow the vapors, and often some entrained oil droplets into the throttle body.
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