Tube from valve cover...... August 23, 2014, 10:57:13 PM Is the tube that goes from the passenger side valve cover, to the throttle body, necessary? Can it be deleted? Quote Selected
Tube from valve cover...... Reply #1 – August 23, 2014, 11:49:58 PM Yes it is part of the closed crankcase pcv system. But you can install a valve cover breather in place of the tube. have a great weekend Quote Selected
Tube from valve cover...... Reply #2 – August 23, 2014, 11:52:30 PM Yep. It's part of the pcv system. It lets metered air in for the pcv system and is also a vent tube for the pcv system at wot. Don't delete it. If you have a speed density system you can get away with a valve cover breather. MAF systems must have the hose as it's providing metered air. If you use a breather in a MAF system you will let in unmetered air, causing idle issues. Quote Selected
Tube from valve cover...... Reply #4 – August 24, 2014, 12:12:03 AM With either system you can eliminate it and install a breather. I never use the stock pipe on any build i do. I always use breathers. Weather Density or MAF it can be removed . Just block off the tube properly and install a breather. Quote Selected
Tube from valve cover...... Reply #5 – August 24, 2014, 10:52:26 AM This is basically what has been reposted on several Mustang websites but this is the original posting by Joel5.0 on www.sbftech.com and I typically listen to this guy as he really knows his stuff when if comes to fuel injection:http://sbftech.com/index.php/topic,119.0/wap2.htmlCan you install an open breather to any of the valve covers if the PCV valve setup is kept? In short the answer is no as this will cause an Unmetered Air (vacuum leak) condition due to air from the atmosphere been sucked into the crankcase. Fresh air intake to the crankcase (specially on MA EFI systems) have to be sourced from the air volume metered/measured by the MAF (reason for the OEM breather hose from the oil tube to the TB on the RH valve cover). Otherwise, a lean condition + idle control problems are likely to occur. If you want to install breathers, the PCV valve must be removed so an unmetered air condition is avoided. The open breather(s) and unmetered air condition, does not apply to SD systems, since the PCV valve is a controlled vacuum leak already provided for by the SD logic.You can read the posts that Joel made and some guys as various questions with regards to this with modified NA engines and forced induction engines. Really a good read as this is what prompted me to get rid of my breather style oil fill cap and after all the messing around with the IAC, TB, and other mechanical means of trying to get the idle below 1,000 rpm it now rests at 850 rpm just like the SCT chip is programmed for.Darren Quote Selected
Tube from valve cover...... Reply #6 – August 24, 2014, 01:49:12 PM I'm installing a tube and hose. Just to be on the safe side. Quote Selected
Tube from valve cover...... Reply #7 – August 27, 2014, 08:26:46 PM i find this fascinating at best because the PCV is a metered vacuum leak. As the matter of fact is meters less when it gets gummed up. And the opposite side is the intake air so to speak and that comes from before the throttle plates. So in my 50 years in this business i would venture to say i have seen many a 5.0 without that tube or it was missing or not connected and oy rotted away. And the vehicle ran perfectly. To prove this just remove the oil fill and see if the idle changes,Or pull out the dipstick and see if the RPM increases. It wont!! So there would be no metered air in the crankcase. Or maybe i am not understanding what Vinny asked. Quote Selected
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