I just failed my emissions test again and the tester said i might need to replace my PCV valve.. he said that will greatly reduce hydrocarbon output becuase most likely my pcv valve is clogged.. I am about to replace mine but i was wondering exactly how that will help my car run any cleaner if the pcv valve is changed? What purpose does it exactly serve? thanks

 

It recuirculates the gases that build up in the engine. The PCV (pressure control valve) acts like a filter, and does not allow hydrocarbons to reenter the intake manifold. There is more to it, I just cant think right now.

 

so i guess if i'm failing emissions becuase of too many hydrocarbons, the pcv valve should defintely be replaced huh?

 

your supposed to change it every 15k miles or so. i just changed mine for the first time at about 56k. however, i did pass smog 2 months ago w/ the og pcv valve. its kinda a bitch to change on a gsr cause its tucked under a hot intake manifold, ouch . i also changed the one on my gf's accord. i changed that one fasted than i could 1/4 mile.

 

The PCV valve is a "positive crankcase ventilation" valve. It removes blowby gasses from the crankcase and reroutes them to the intake manifold where they are sent through the engine to be burned. It is unlikely that by just replacing your PCV valve that you will pass emissions. Plugged PCV valves in Honda's are rare to nonexistant. If you only failed by a small margin, an oil and filter change might bring your emissions to within state standards. If your vehicle failed by a larger margin, you need to look deeper. How is the ignition system? (spark plugs, distributor cap, ignition rotor, spark plug wires) Have the valves been correctly adjusted within the past 15-30k? Is your timing belt correctly installed? I have seen more than a couple of cars fail because the cam timing was off by one tooth. Is your air filter dirty? A plugged air filter will increase CO emissions. Well maintained vehicles tend to pass. A car that has been neglected is a crap shoot when it comes to passing the smog test.Good luck.

 

(pressure control valve)

it stands for positve crankcase ventelation

 

i have to disagree with you on how honda's pcv valves dont get clogged.. just checked mine and its pretty damn clogged! you can tell when it doesn't rattle.. the new one does.. anyway i've heard of the honda's pcv valve clogging all the time.. i just wanted to know what purpose it serves

 

It could be that. It could also be a bad O2 sensor. And yes it can go bad without throwing a MIL code.

 

The way to test for a clogged PCV valve is with the engine running. Put your finger over the PCV valve orifice with the engine running. If you feel vacuum, it's not clogged. If there is no vacuum and the PCV hose is good-then the PCV valve is probably clogged.

 

Yea i was wondering what the **** a (pressure control valve) was until i saw the correct version of PCV as "positive crankcase ventilation". Hehe

 

maybe your headlight fluid needs to be changed- it should be done every 7,500 miles- would you like to have that done today?

PCV valves are the biggest quick lube rip off- valvoline instant oil leak and jiffy squirt are always trying to get you to replace them. A new Honda PCV valve doesn't rattle- unless you shake the **** out of it- it has a plastic valve in it. Valvoline will sell you a big *** one size fits nothing PCV valve with a big metal plunger in it. Sure it is a possibility- just venting.

 

So I guess with all you've just said you're basically making a point that pcv vavle replacement is not neccesary at all? hmmm

 

so wait, that fram PCV valve they sell at kragen for 3 bucks with metal plunger in it is not the correct piece? will it not do its job correctly? do i need to get a different brand in order for it to work right?

 

no way -- change it!....it's only a rubber tube.
I had this problem with my CX engine when my car was stock. That PCV tube was pinched from being old and was the key in failing me on the smog dyno. Put a new rubber hose as a replacement and passed smog.

change it out or try cleaning it out, re-smog....no biggy.


[Modified by Katman, 1:44 PM 4/4/2002]

 

I know, I know :I'm a cheapass - but is there any reliable way to clean the gunk out a PCV valve?

 

lol..
yeah there is a way to clean it out.
Scrounge up about $1.00 in change and head over to home depot or OSH !

 

Carb cleaner will clean anything that is gunked up. However, if the hose is gunked up it is probably collapsed and brittle and should be replaced. You can use the $3 fram PCV valve if you want- it's just that I have seen several aftermarket PCV valves that have caused idle problems and excessive oil consumption which equals excessive HC - that's my 2 cents.

 

YOUR GONNA WASTE MORE MONEY ON CARB CLEANER THAN THE VAVLE
MINE WAS$2.50 GO GET A NEW ONE IF YOUR THAT CHEAP THEY FIT PERFECTLY
IN YOUR POCKET

 

A Honda PCV valve is something around $16.00.