White smoke on deceleration

[GreenV8S]

Bdevo3 said:

the standard pcv valve are a weak point and even from new have a tenancy to stick open with aftermarket exhaust and induction and allow oil into the intake. Higher boost makes it worse and causes the dip stick to pop up and all sorts of nastiness. So the Internet tell me. Common issue on early evos apparently

I can see how that would be a problem. How does the check valve help?

[Bdevo3]

The pcv valve itself is a check valve which opens under vacuum to release crank case pressure when it closes the crank case draws clean air from the intake pipe. When it sticks open when the car is in boost the oil is drawn through it into the intake to be burnt causing the smoke. Putting in the check valve is essentially putting in a second pcv valve so if one sticks open in theory the second should stop any oil getting through

[GreenV8S]

Bdevo3 said:

The pcv valve itself is a check valve which opens under vacuum to release crank case pressure when it closes the crank case draws clean air from the intake pipe.

Are you sure about that? I've never seen a PCV system that works like that.

[Bdevo3]

GreenV8S said:

Bdevo3 said:

The pcv valve itself is a check valve which opens under vacuum to release crank case pressure when it closes the crank case draws clean air from the intake pipe.

Are you sure about that? I've never seen a PCV system that works like that.

My apologies I had a few pints in me last night it draws air from the air intake pipe while the pcv is open. I've used these diagrams from dsm tuners