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Discussion Starter #1
I'll preface this by saying I'm still learning how this engine operates, and I'm slowing working through leaks while pressure testing. I'm pretty sure I've got the pressure test setup correctly (using a 3sx adapter), I've plugged the few places I'm supposed to (marked in yellow on my photos below). However, the primary leak is now my BOV (it's just shooting out air as fast as I can put air in). I've read people mention "tighten the BOV", but I have not found any instructions so far... and I'm really wondering if I just need to replace this BOV. Also, I'm seeing some air blow out a vent hole (on the second photo below).

I would love to hear suggestions or thoughts. My gut tells me I'm gonna need a new BOV (or a used one).

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Nice post with pictures lol!

Some valves are probably just open. If that happened during a leak-down test, then you would want to be concerned. Also, that seems pretty typical of the factory, plastic valve. Inexpensive drop-in upgrades include the metal units from a Lancer Evolution or a 1G DSM with flange adapter. Some aftermarket ones can be found for a good deal.

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Start your pressure test by removing the Y-pipe connection to the throttle body and "blocking" that with something. You can usually just use a folded up plastic bag or something and then re-clamp the y-pipe. This isolate the intake track from the TC/plenum/manifold. After fixing those leaks, move forward.
 

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Thanks @bboyalan! I turned over the engine a couple times, and the air is still blowing from the crank case during the pressure test. Could this be happen if my Valve Stem Seals are leaking? The reason I ask is, my car loves to blow blue/white smoke for a little while, until is burns off after a few minutes. I suspect the VSS needs to be replaced also. Just not sure the flow of air during this pressure test.

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Do you still get pressure in the crankcase when you pressure test with the Y-pipe to TB connection blocked? See my previous suggestion. Block that and pressurize the intake system first. Pressure in the crankcase can also be from air going past the rings if a intake valve is open on one of the cylinders.
 

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Discussion Starter #6
@jrhorne Thanks for the suggestion! Yes, I did as you said (plastic bag blocking the TB). I'm not seeing any leaks on that side of things anymore (I've already fixed a few... mostly the downpipe to the rear turbo). Now, regardless of how I turn my engine, I'm getting a slow blow of air out of the crank case. Could this mean that my piston rings are bad? Perhaps an engine rebuild is in my future? Is there any other explanation for why air would be escaping the cylinders and exiting the crank case? Thx!
 

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If you plugged all the breather hoses, etc, then yeah its probably just air going past the rings. Doesn't necessarily mean you need a rebuild... the rings will never seal perfectly. If you really want to test the condition of the rings do a compression test.
 

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Stock BOV is known to leak like a sieve.... Most all of them do. I'd definitely go for an upgrade. I do like the EVO valves Alan mentioned. It's not a true boost leak in the sense of boost escaping to atmosphere, as it's recirculated back into the intake. But it does bypass some of your boost pressure.

You will always get minor leakage out the crankcase... I usually hook a long hose to it and route it away from my work zone so it doesn't distract me from the real leaks. I would make sure your PCV is holding though... If it's leaking, you will pressurize the crankase under boost, which is never a good thing.
 
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