I gotta question for you guys. The other day I was under the hood and noticed that the vacuum hose from my PCV was missing. I don't know when I lost it or where it went, but it appears the nipple on the top of the PCV broke off. What exactly does this little thing do and should I replace it? My idle has been a little off recently, could this be a result?
Thanks for the help.

'91 FC n/a

 

ANY IDEAS....

 

I broke the nipple off of mine when doing a silicone hose job many months ago, and my car still runs fine. The RX-7 "expert" at the local Mazda dealer told me it's just for oil filler neck ventilation, and something to do with the atmospheric pressure system, but he said it should not affect my car's functioning.

 

I've no idea what it's purpose is, but I figure that if it is there in the first place, then it must have some purpose. I'd check into it until you find out for sure. Better safe then sorry. Does anyone else know?

Derek

 

There's lots of stuff on our cars that is there in the first place, and it does have a purpose, but it's not necessarily needed. Look at my engine bay, and look at a stock one. Lots of stuff that had a purpose is gone:

 

Wow! Very nice...and very clean. Are you running without the PCV? Where did you get your colored vacuum hoses?

 

Does look pretty nice. You've removed the emissions equipment, and maybe some additional accesories. The "PCV" is neither, and unless part of the emmissions, and unless you are positive, then I still say better safe than sorry. I'm not saying that you are wrong, but rather that the post creator should check more into his problem until positive about the solution, and in turn, whether or not he actually needs the part. YOU may not need it, but maybe he does with his setup. Just be careful about removing things that you are unsure of.

PEACE,
Derek

 

Hey AKABILLY, here is the hot skinny on the Purge Control Valve - Mazda's version of the Positive Crankcase Ventilation valve (same initials - coincidence? You decide ). On top of the valve is a line that should go to a port which will have vacuum only after the throttle is opened at least a little. On the bottom of the valve is a line to engine vacuum, and a line to the oil filler neck. Howzit work? you ask. At idle, there is no vacuum to the top of the valve, so nothing happens. As you give it throttle, vacuum is applied to the top of the valve, and it connects the 2 lines on the bottom. This applies engine vacuum to the oil filler neck (to a rotary's "crankcase"), thus sucking out excessive vapors. Same idea as a PCV on a boinger! Now, if the vacuum line on the bottom of the valve is off, you will have a vacuum leak at idle, which will cause problems. Any line being off will cause a vacuum leak, just not at idle. Hope this clears it up for ya.

Irv, Keith's dad

 

Thanks for the clarification Irv. I've read many of your posts and appreciate your contributions to the forum. We need more kind, intelligent rotary enthusiasts like you around.

 

Thank you Irv, Keith's dad.

I ordered the PCV from the Dealer Parts Dept for $35.00

Thanks for your help everyone.

Billy
'91 FC n/a

 

Thanks for the compliments. I do still have the PCV on it, but the nipple is broken off of the top of it, effectively making it not work at all from what I got out of Irv's description. I got the vaccuum hoses from AutoZone.

NCSublime:

Actually, I still have all of the smog equipment on it, at least until I get kliftin's race pipe.

 

The purge valve also passes evaporative fumes from the gas tank and the charcoal cannister to the intake manifold via the oil filler neck.So if the purge valve is not working properly--strong fuel smell in the oil neck.

 

Yeah, I've got the Bonez race pipe on mine, but haven't yet totally removed the SAP, because I'm still waiting for the block off plate to arrive. It's just tied up under the car with the hole plugged up.

 

Aw, shoot! I'm embarrased (blush, blush)! :p

Hey, I gotta tell Keith that his old man Rocks and Rolls ..er, something like that! He should be home soon!

Nice to be appreciated anyway. Have a good day all!

Irv, Keith's dad