Connection from top of TB to passenger valve cover?
04-09-2004, 09:28 AM
#1
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Connection from top of TB to passenger valve cover? What does the connection from the top of the throttle body to the front portion of the valve cover do? I'm not talking about the PCV connection, but rather the connection towards the front of the valve cover on the passenger side. I think I was sucking some oil through this connection into the intake along with the PCV connection...
04-09-2004, 10:57 AM
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It is the vent tube, part of the PCV system.
I also get a lot of oil through this tube. When I ported my throttle body I spent half an hour cleaning the oil out of it first.
So far I have never seen anyone remove it, or post any issues that would arrise by removing it.
I also get a lot of oil through this tube. When I ported my throttle body I spent half an hour cleaning the oil out of it first.
So far I have never seen anyone remove it, or post any issues that would arrise by removing it.
04-09-2004, 04:02 PM
#6
I got severe oil foam in mine after H/C on my 99 forged engine; even have a pic on my website showing the TB. I might have to try an in-line filter or cap it and put a filter on the end of the hose so the valve cover still gets fresh air. I did a search and found mmiller from this site researched this back in 2002 but never came up with anything either. No one believed him that oil was getting pushed back through the tube TO the throttle body. Well, I believe him, especially after seeing mine.
04-09-2004, 04:57 PM
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when i put T&D Rockers on my car and had to cut out the baffle so the VC/Spacer combo would work... i had tons of oil in it...
now I just run LS6 PCV and breather on the passenger side... everything else is capped
now I just run LS6 PCV and breather on the passenger side... everything else is capped
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04-09-2004, 05:20 PM
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If my understanding is correct the TB does not have a vacuum on that hose. It does not pull from the valve cover to the TB, rather it pulls from the TB to the valve cover to keep vacuum and positive pressure inside the crankcase. Its so fresh clean air from the filter is pulled from the TB through the valve cover circulated back through the engine pick up contaminates be pulled back through the PCV and be burned off. Im pretty sure about this guys well not really ??? hahaha correct me if I am wrong. If I wasnt so lazy Id go outside and check myself for vacuum but nawww f that. I THINK Im right though no burns intended THANKS. Good Luck
04-09-2004, 06:44 PM
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Under WOT there is no drop across the TB but a substantial
drop across the MAF (if screened), lid (if stock) and filter.
The vacuum is probably a fraction of a PSI. But at the same
time you are pressurizing the crankcase with blowby gasses
and whipping up a nice oil fog off the rockers. The gas flow
will take the mist out to the TB through both the valve
metered PCV draw, and the totally unchecked PCV makeup
air line. Both are at lower absolute pressure than the crankcase
and both will get spoogy. The worse your blowby the worse
this aspect of oil uptake.
drop across the MAF (if screened), lid (if stock) and filter.
The vacuum is probably a fraction of a PSI. But at the same
time you are pressurizing the crankcase with blowby gasses
and whipping up a nice oil fog off the rockers. The gas flow
will take the mist out to the TB through both the valve
metered PCV draw, and the totally unchecked PCV makeup
air line. Both are at lower absolute pressure than the crankcase
and both will get spoogy. The worse your blowby the worse
this aspect of oil uptake.
04-09-2004, 07:10 PM
#11
jimmyblue,
What you are saying is making sense. My mechanic said if you only start the car and run for a short while, the 'froth' is worse because the oil hasn't warmed up all the way. Combine that with my forged pistons ( they are loose at first, you can hear them big time at start up till they warm up and expand ) and that would explain alot. I drive for sometimes only 15 minutes - to work and home then park it. Maybe capping off the upper TB inlet and going with a breather in place of the oil cap would work? Or, don't worry about it much? I just put in place the AMW catch can to handle the PCV side of things.
What you are saying is making sense. My mechanic said if you only start the car and run for a short while, the 'froth' is worse because the oil hasn't warmed up all the way. Combine that with my forged pistons ( they are loose at first, you can hear them big time at start up till they warm up and expand ) and that would explain alot. I drive for sometimes only 15 minutes - to work and home then park it. Maybe capping off the upper TB inlet and going with a breather in place of the oil cap would work? Or, don't worry about it much? I just put in place the AMW catch can to handle the PCV side of things.
04-09-2004, 08:36 PM
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Breaking the PCV open and using a breather on the
makeup side will be a source of unmetered air that
may affect your idle and low throttle mixture some.
The PCV air is all downstream of the MAF and blowby
is pretty mixture-neutral. But breather air wouldn't be.
Separators I think are the way to go. I got a pair of
small compressed air ones (one for each way on the
PCV) but haven't gotten aroung to mounting. Right
not I only have one of those cheesy inline plastic
sump type fuel filters inline w/ PCV suction side. Same
idea, cheaper and uglier. Way cheaper.
makeup side will be a source of unmetered air that
may affect your idle and low throttle mixture some.
The PCV air is all downstream of the MAF and blowby
is pretty mixture-neutral. But breather air wouldn't be.
Separators I think are the way to go. I got a pair of
small compressed air ones (one for each way on the
PCV) but haven't gotten aroung to mounting. Right
not I only have one of those cheesy inline plastic
sump type fuel filters inline w/ PCV suction side. Same
idea, cheaper and uglier. Way cheaper.
04-10-2004, 01:34 PM
#14
TECH Senior Member
Uncap the hose at the valve cover, run a 90 degree connection upward, put a clear fuel filter on it and re-attach the hose to TB. That and a catch can for the PCV = a perfectly dry intake & No more oil sucking. 
04-12-2004, 08:11 AM
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thanks for the help guys. I think I have it covered with the AMW catch can on the PCV side and the seperator on the "upper throttle body" connection. I'll monitor the seperator for oil...
-Jason
-Jason