PCV valve question
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Joined: Feb 2013
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From: Gibsonville,NC
PCV valve question
Hello all, I have an 86’ XLT Lariat, 2wd, standard cab, lwb with 302 auto w/od & EFI, all stock. I did an advanced search looking for the correct PCV configuration & didn’t find exactly what I was looking for. Reason being, I recently replaced my oil fill cap with cutout for plumbing to the air filter box. Initially I had a filler cap from a straight 6cyl without a baffle & rotted away gasket. I was getting a ton of oil blown up into the air filter housing. I was chasing oil leaks & replaced the filler cap, elbow, hose to af box, crankcase breather filter & air filter. The elbow at the filler cap was replaced with a new PCV valve to catch any blow by. This has not been the case, as oil is still getting into the af box. Then to top it all off I found another PCV valve on the opposing valve cover with a hose running to the backside of the motor, which hasn’t been changed yet. So, who here knows if I’m supposed to have 1 or 2 PCV valves? Is 2 better than 1 when trying to control blow by? Do I just have too much oil pressure? Anyway, any and all advice on the matter would be greatly appreciated.
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With the other PCV it should have suction on it when the engine is running. If it doesn't, then you need to troubleshoot why it doesn't, that would be your oil leak and excessive blow-by problems. It should hook to the intake of the engine somewhere.
The other hose that went to the air filter box is the air intake and gets no PCV valve. The PCV side sucks, the air filter box side lets air in. If you get it all working and are still having problems, then most likely the engine has excessive wear. If you want to keep it going, keep the one PCV valve side sucking on the one valve cover, and then take the other side with the oil fill and instead of running it to the air filter box, run it down with a longer hose into a homemade jug to catch the excessive oil, but still let it breath.
The other hose that went to the air filter box is the air intake and gets no PCV valve. The PCV side sucks, the air filter box side lets air in. If you get it all working and are still having problems, then most likely the engine has excessive wear. If you want to keep it going, keep the one PCV valve side sucking on the one valve cover, and then take the other side with the oil fill and instead of running it to the air filter box, run it down with a longer hose into a homemade jug to catch the excessive oil, but still let it breath.
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Basic diagram:
https://www.aa1car.com/library/pcv.htm
From '79 with a carb:
https://cimg0.ibsrv.net/gimg/www.for...4d9ba8cd4b.jpg
Can't find the one I want for an EFI motor, but the air supply comes from the air box, PCV gets vacuum off the manifold, same principals as the carb'd engines.
https://www.aa1car.com/library/pcv.htm
From '79 with a carb:
https://cimg0.ibsrv.net/gimg/www.for...4d9ba8cd4b.jpg
Can't find the one I want for an EFI motor, but the air supply comes from the air box, PCV gets vacuum off the manifold, same principals as the carb'd engines.
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