AlphaKennyWun

On a 91 Civic si... got it used with 120,000. Unknown history the car had been sitting a while. Car ran terrible at first but after changing oil, filter, o2, cap, rotor, spark plugs, wires, air filter, tranny fluid, axle, bearing, the car ran much better.

However for last 10,000 miles the car still had idle problems, blow back and lumpy acceleration. I thought I needed a valve job and did not think the PCV valve would make too much a difference. Well I was wrong. Yesterday I got around to changing it and it took me 3 minutes with a pair of pliers.

What a difference. After changing it I have not had any idle problems or lumpy acceleration. There is still some blow back under WOT but I read thats normal due to 0 vacuum at WOT.

My suggestion is if you do not know the maintenance history of your car, just change this part out. If it was gunked up like mine or hasnt been changed in a while you, you will feel a difference. Very easy.

honda.lioness

On my 91 Civic LX, I checked the PCV valve in 2003 at about 140k miles. I am the original owner of this Honda and had never touched the PCV valve before. It was full of a black waxy buildup. I replaced it. About the same time I got a new distributor housing. My MPG shot up around 10-20%. I have seen chatter on the net about how a clogged PCV valve throws off some ECU sensor signals. Now I take the PCV valve off about once a year and clean it with either Carb Cleaner (which typically on the can mentions that it is good for PCV system cleaning) or PB Blaster.

jhammond_82

iTrader: (1)

this is good to know. i never would have thought of this. my 91 dx stumbles all the way throught the rpm range. i wonder if this would fix it. it smokes, and **** but i think thats a different cause. but the stumbling and stuttering. makes me think now.... thanks for bringing this up!

honda.lioness

For the archives yada: When did your car last get new spark plugs, wires, dizzy cap & rotor? How old is the oxygen sensor? Are all these parts OEM? Timing been checked recently?

I would not rule out the cause of the smoke also causing the rough running.

Mr.Death

Still vacume at WOT.

AlphaKennyWun

I stand corrected. Yes still some vacuum maybe .7"-1.2" on my turbo GSR's boost gauge it did register some at WOT

munky69

so u wheren;t boosting anything? LOL

Tyson

just becareful removing the old PCV valve. it tends to break. but the only way to take it off is to just pull on it. hard to pry it off from the side.

if it does break, just gotta take a pick and get all the bits out.

have a replacement ready on hand.

honda.lioness

On certain submodels of the 88-91 Civic and CRX, the PCV valve is metal and threaded. So apply PB Blaster as needed; get the right size deep socket (14 mm IIRC); and unscrew w/breaker bar. The other submodels get the warning Tyson provides above.

scottmog

im very interested in changing this as my crx has these same symptomes. can someone let me know where this part is at, as the search function isnt working right now

rattlecannedEF

so wheres is this pvc valve thingy on my civic? will it get rid of the smoke my car spits out?

90_hatch_b16

its on the firewall side of the engine, on or under the intake manifold and has a hose connected to it.

rattlecannedEF

got a pic so i can relate?

honda.lioness

Pretty decent drawings appear at bkhondaparts.com. Put in your Honda's year, model, etc. Go to the engine section. Then go to the "Breather Chamber" section. List all parts and you will be able to identify the PCV valve. It's a good idea to have the new PCV valve in your hand to help identify the old one on your car. OEM PCV valves arguably are worth the extra few bucks they cost.

Hard to say about the smoke. Either way, the PCV valve is cheap enough to justify changing at least every ten years. Certainly at least remove and clean the old one with carb cleaner once a year and see if this helps.

AlphaKennyWun

haha I had many different turbo set ups and broke in several engines. Thats when the turbo was not hooked up but the gauge was.
Facing the engine its on or near the furthest right intake runner of the IM. Its sticking straight up on top, has one hose attached to it and the base is what you pull out of the manifold but be gentle removing it.

Since changing it I have considerably less smoke and smoother acceleration. I cant take a guess at MPG yet because I am currently mashing the pedal every chance I get.

jacksonww

Item #7 right?

AlphaKennyWun

it looks like #7 but mine went straight into the manifold and had only one hose attached at top. That picture is misleading in a way because it looks like the base is going into another hose.

scottmog

i couldnt find the freaking valve... someone help me out please.

https://honda-tech.com/forums/showth...7#post37364077

Tyson

do you have MPFI or DPFI?

MPFI pcv valve is located between the #1 and #2 runner.

another way to find it is follow the big hose at the top of the intake manifold (the one in the middle of the 3) down, it goes right into the PCV valve.

if you have DPFI, good luck, i dont know.

scottmog

sohc zc so mpfi.

ill take a look though ty. and by runner u mean intake manifold valves correct?

also "another way to find it is follow the big hose at the top of the intake manifold (the one in the middle of the"

in the middle of the what? lol

scottmog

i am the biggest fkn idiot ever tyvm tyson i found it.

Tyson

sigh...



top of the intake manifold. 3 hoses. see the fat middle hose? follow it down, below the FPR. you can see it in the pic, its a black circle.

Tyson

and i dont think it will affect your rough idle. clean your IACV first if you havent already.

scottmog

ya i cleaned out my idle air control valve and my fast idle valve and i still sometimes get a lil choppy idle.

also! bigger problem lol. the shitty pcv valve broke from the top when i tryed to take it out so now all i got is a stub. how did u get yours out?

jacksonww

also! bigger problem lol. the shitty pcv valve broke from the top when i tryed to take it out so now all i got is a stub. how did u get yours out?[/QUOTE]

I did the same stupd thing except in the reverse order. Mine fell apart while putting it back in. A quick trip to the parts store and 4 bucks later I was back in business.

Oh.. FYI, long nose plyers will get the stub out.