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Discussion Starter · #1 ·
I'm wondering if anybody here has installed a 3-way air/oil separator on a 5.0. I didn't want to pay the $150+ for a catch can so after perusing amazon I found this 3-way can. It has 2 inlets and 1 outlet. My thinking was there are 2 pcv outlets on the engine. One on the passenger side and one on the driver side. So the routing should be simple enough. With the passenger side being the "main" side that produces the most blow-by (as I've read many times on AM and CJP), I figured that side would be the best to route the catch can outlet to. I'm not sure what part of the intake the passenger side pcv routes to but I would use it as the "return" from the catch can outlet. Still with me? Anyway, that leaves the original driver side pcv return, located on the air intake tube, open. So I bought, believe it or not, a 1/2" chair leg cap to use on that inlet (pointed to by red arrow in pic). A little black tape and it fits fine and blocks the intake. After completing the install I started the engine. No check engine lights or anything like that came on. Glad for that. So I did little experiment and pulled the driver side hose off the pcv valve and holy kamoly batman...there's a very large sucking sound coming from the hose (which leads directly to one of the inlets on the catch can) plus the engine started to die. Obviously it was vacuum and pulling the hose resulted in a huge vacuum loss which caused the engine to run badly. So I quickly put the hose back on the pcv valve and the engine returned to normal idling.

So here's my question: Does modifying the pcv system, such as I have done, cause engine vacuum issues to surface? Doesn't anyone have any experience with using these 3-way cans? Does anyone think this setup is kosher? Any info is gratefully appreciated ! Thanks !



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