PCV system diagram/how to properly set up the hoses

Mateo

Member
My PCV system isn't working as it should, because it is super smokey and it stops smoking without the oil filler cap on. I currently have it routed from the PCV outlet, to an A80 Supra PCV Valve, to a catch can which is routed back to the intake manifold. It smokes pretty bad during shifts/lift off so I'm wondering if I have something incorrectly set up.
Does anyone have any ideas?
 
Do you have a USDM ST165 with the original 3S-GTE?

I don't know if the USDM ST165 3S-GTE is similar to the USDM ST185 3S-GTE, but for ST185's, there is no PCV valve in the PCV system. There is a vent hose connected between the valve cover and the intake manifold. If your routing is unblocked, it should not make a difference regarding if your valve cover oil fill cap is on or off (in general). Just wonder if you have your routing for the crankcase blow-by blocked in some fashion (like sludge deposits in your valve cover, or a very dirty intake manifold, or something blocking the hose in between).

If you have excessive blow-by, it would be more pronounced when the engine is under heavy load. You might be taxing the capacity of a good working PCV system if your blow-by is excessive. What are your cylinder compression pressures when taken in accordance of the service manual?
 

Mateo

Member
93celicaconv":1fuqwk49 said:
Do you have a USDM ST165 with the original 3S-GTE?

I don't know if the USDM ST165 3S-GTE is similar to the USDM ST185 3S-GTE, but for ST185's, there is no PCV valve in the PCV system. There is a vent hose connected between the valve cover and the intake manifold. If your routing is unblocked, it should not make a difference regarding if your valve cover oil fill cap is on or off (in general). Just wonder if you have your routing for the crankcase blow-by blocked in some fashion (like sludge deposits in your valve cover, or a very dirty intake manifold, or something blocking the hose in between).

If you have excessive blow-by, it would be more pronounced when the engine is under heavy load. You might be taxing the capacity of a good working PCV system if your blow-by is excessive. What are your cylinder compression pressures when taken in accordance of the service manual?

Yep, still original gen 1 3SGTE with a rebuild 100K miles ago. Don't remember the specific compressor numbers, but they were good when I bought the engine, same with a leak down test. I currently have the PCV outlet just to a catch can which is to the turbo intake which seems to produce the best results, with some smoke at idle still.

Factory there is no PCV VALVE, which is why I used an A80 Supra turbo one, but I currently have it disconnected, but the reason I tested with the oil cap is that it acts as a pressure relief valve and if it's smokey at idle and you remove the cap you let out a ton of the crankcase pressure and if it stops smoking then you know you have excess crankcase pressure (what I did to narrow it down, because I already did valve stems and have good comp. along with a good Supra CT26)
 
I'll assume, by your response, you removed all original PCV items now, still had smoke and high crankcase pressure (by testing with your oil fill cap removed), and you are running your new hose connected to your valve cover directly to the intake of your turbo (which reduces your engine smoke a lot). You believe you have proper engine compression pressure.

The only thing that seems to fit this pattern and give you your issue is a very gunked up valve cover that is partially (mostly) blocking the PCV vent going out.

Not sure how long you've driven it, but if the car had previously been run with regular dino oil, given the heat that engine builds, it is very possible you have sludge in the engine and have the problem described caused by sludge in your valve cover.

If sludge in not your problem, then you must have excessive blow-by at your pistons, which would typically be observed by low compression pressure values (at least on one cylinder). Could be a similar cause (dino oil sludging), where the rings are stock in the piston grooves and are not putting adequate pressure on the cylinder walls.

Can't help you any more than this. We have two ST185's in the family, all stock, absolutely no smoke out of the exhaust at any time. PCV passages are open & clear, compression pressures checked and in the normal range.
 

Mateo

Member
Yep that's exactly how I have it hooked up, straight from pcv outlet to turbo intake and it still smokes.
What's a good way to clean out the PCV? Just take off the valve cover and just clean it up? I swear I did that when I painted my valve cover, but I'll try again.
 

abeans

Member
Do you have a breather from the valve cover to the intake still? PCV's require both.

The valves are also directional you sure you have it facing the correct way?
 
abeans":3rrxiuby said:
Do you have a breather from the valve cover to the intake still? PCV's require both. The valves are also directional you sure you have it facing the correct way?
Does the 3S-GTE have a PVC valve? The service manuals don't show or reference one. The two ST185's we have don't appear to have one.

Regarding cleaning out the PCV system, might want to check if it flows easily first or not. Take the vent hose off the intake (or the turbo as you have it hooked up now) and, with the engine off and the oil fill cap off, blow back on the hose towards the valve cover. Does it flow quite freely? Maybe even suck back on it to see if it flows in the proper direction properly. Does it flow easily? If yes, you don't have a PVC flow problem. But if no, take the hose completely off on both ends and blow through it. Does it flow easily then? If yes, your need to remove your valve cover and have it solvent cleaned in a a parts cleaner overnight to get all the crude out of it (some large auto parts dealers that have shops will have cleaners like that for things like oil pans and valve covers and such).
 

abeans

Member
93celicaconv":2beug05r said:
abeans":2beug05r said:
Do you have a breather from the valve cover to the intake still? PCV's require both. The valves are also directional you sure you have it facing the correct way?
Does the 3S-GTE have a PVC valve? The service manuals don't show or reference one. The two ST185's we have don't appear to have one.
Nope.
OP:
Factory there is no PCV VALVE, which is why I used an A80 Supra turbo one, but I currently have it disconnected
 
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