Ef4doorwagon

Ive been somewhat reading about this, so im not running with a pcv hose... i have the part that goes on the manifold capped off, and the breather box just there, no hose on it.

So my cars idle has been very low, havent been able to find a solution.
I have noticed that if i take out my adjusting screw, extra air is sucked in and my idle settles at 750. But it hurts my cars performance.

So maybe because im not using a pcv hose, the intake manifold is not getting those bypass air gas stuff, and thus not getting "sufficient" air, causing low idle?

If anyone knows about this, please help me out.

Quick note: deleted fitv, cleaned and cleaned and cleaned out the iacv, replaced hoses, cleaned throttle body, changed intake gasket and tb gasket. Have tried adjusting the idle, but doesn't help.

Any help is appreciated.

F22Master

Have you tried setting your idle by the procedure in the service manual?

Ef4doorwagon

Yep. Let car warm up, unplug iacv, adjust idle to correct rpm range, turn car off, reset ecu by pulling ecu fuse or disconnecting the neg on battery. Tried that, and idle will not rise, only rises with extra air coming into the manifold.

F22Master

Did you jump the service connector? The ecu will not try to 'learn' if the service connector is not jumped.

Ef4doorwagon

Is that those 2 wires that when connected, throws the CEL codes? I have those on a toggle switch, do i have to flip it on then adjust my timing or something?

Tyson

1. the PCV valve is not important. its a tree hugger thing.

2. allowing the engine to breathe while running is important.

3. making sure the valve cover can vent IS important.

4. the valve cover hose doesnt need to go back into the intake.

5. dump it into a catch can.



what do you mean, losing performance? how are you testing it, or judging performance?

br8crumb

like tyson said.. the pcv is not important. as long as the INTAKE MANIFOLD is capped off so there is not a vac leak, running no pcv will not hurt your idle.

*atm* i have the black box open with no hose attached so it vents into the engine bay, and the manifold is capped. i have ran it for well over a year because i have not been worried enough to remove the back box and cap the back of the motor.

as for a catch can?? the valve cover has a hose that connects to the intake.. and usually the block has a box that the pcv connects to the manifold.. just cap off the box at the manifold so no leak, and put a filter directly onto the valve cover so none of that crap will go into the manifold.

as for performance. any check engines...? have u messed around with any sensors aka tps.. did u mess with ignition timing..? and even stupider problems would be something as simple as ur plugs or cap needs to be changed and ur currently getting less spark which can make ur top end feel sluggish..

*need a lot more info to really figure out issues though.

95Sedan

there should be no problem venting PCV to atmosphere this is a widely discussed subject among MANY different vehicles.

have deleted my PCV on my cobra venting to atmosphere with NO problems.. runsgood

Tyson

makes no sense to put a filter in between the intake and valve cover.

a filter will just get clogged, and still pull oily vapor into the intake from the oily tampon youre calling a filter.


just dump it into a catch can. vent to atmosphere. done.

Ef4doorwagon

What do you guys mean by catch can?
I meant it hurts performance, as in, when i let excess air into the manifold, my idle sits perfect, but acceleration is slow,

Right now, the valve cover has a hose that goes into the air intake,
I did now fix my ignition timing, first i did that switch thing, where the check engine comes on, then adjusted ignition, and then unplugged the switch.

My idle is real low, almost wants to stall out. If i start backing out the screw, the idle starts fluctuating, i have to keep it all the way tight, but doesnt solve my low idle.

Tyson

catch can is just a container outside of the engine to hold the condensed vapors. can be some pimpy welded aluminum piece, or a soda bottle. you could also just let the hose drip down to the ground... but why not just "catch" it in a "can".

ok so youre measuring "performance" by a butt dyno. thats not so accurate to tell you much.

keep checking for vacuum leaks.

and from my experience, following the factory method of setting idle has never been successful. i just screw the idle screw all the way in, and back it out until it reaches the right idle and call it done.

thesmogman

Are you sure you got the correct tb gasket? I had to make a hole in the one I got for the iac. Then what do you know it worked.

PCV isn't your performance problem. just run a hose from the VC out the bottom of the car somewhere. Double check your timing and verify your cam timing hasn't jumped a tooth.

Ef4doorwagon

I check my ignition timing daily, ive had to adjust it a few times

So the hose from the valve cover, shouldnt go on my intake? I havean aftermarket short ram one, do i cap off the hole on the air intake? Or leave it like that for extra air?

My car on the way to autozone, actually idled so low it died, but it started back up, ive made my throttle cable tighter, so now when i press on gas pedal, the tb plate gets stuck a lil open, and i try to level the idle to about 800, if that makes sense.

br8crumb

you shouldnt have to " check " ignition timing... either move it clockwise or counter clockwise.... 1 way will raise ur idle.. 1 way will lower ur idle.. it is OK to be slightly advanced, as long as you dont have pinging which can hurt ur pistons. being advanced can be noticeable for power gains and being retarded can be felt as a power loss.

same thing goes for the throttle body screw.. do it by ear. let the car warm up.. screw it all the way in and slowly start unscrewing. it will be obvious when you have over done it

Ef4doorwagon

I have my dizzy advanced as far as it can go, the car runs fine, for some reason maxing it sits at 16 btdc.

As for the tb gasket, it fits fine, but maybe your right about it blocking an air passage for iacv, ill have to check that.

And adjusting the screw doesnt help, if i back it out alot, it settles for a bit but then starts to idle hunt,

This idle thing is stressing me out man... its the only reason i dont like my car

Ef4doorwagon

O wow i just learned something new. When adjusting the idle screw, it messes with ignition timing!!! I wish someone had told me that!

I am a novice at mechanical stuff tho, so yeah...

As i was adjusting my screw i kept checking my ignition timing via timing light set at 16, everytime i kept making the idle rise, the crank pulley mark( i marked it with white out) kept moving closer and closer to the tdc mark thing. As this whole time ive been messing with the screw, messing up my timing, and thats WHY ive had to keep adjusting my ignition!
Now i corrected my idle to where the tdc crank marks stuff line up, and idles good now, only i think the vibrations might make the screw move, but ill probably get some thread lock.

Thx for the help everyone. Really appreciate it.

br8crumb

all the way advanced....? really hope u dont melt ur pistons....

4drEF

I didn't see any replies to this so here goes.
YES - you need to jump those wires, or in your case flip a switch.
It will disable the electronic ignition advance so the ECU won't be making any adjustments while you set the ignition timing.
If you don't short the wires together, then the ECU constantly corrects timing. You can turn the distributor either way and it looks good on the timing gun... wrong way to do it.

d4g4m

I wanted to check my timing. Manual says 'jump' the connector hanging under dash at passenger side. Was wondering what was the purpose of that thing. Was going to post a thread to find out but now I know.

Scottmcc

Glad to see everyone helped him out. I, too, tinkered under my hood for idle issues. Started with throttle cable ( too much, too little ) just about right. No more low idle stalls. I also degreased the TB spring & lightly re-oil.

I also have a Haynes manual for my 1990 Civic CRX Si. Learned alot over the years.

Still have car @ 349,000 +/- miles as my daily driver with the 1990 body rust issues ( darn ).

Scottmcc

May I ask a question about the PCV system?

My 1990 CRX Si with a D16 swap ( original was losing compression), I was trying to REMOVE the PCV valve "in" stem from hose ( a piece broke off & would push in fully. The plastic pipe BROKE ( poop ). I've been driving to atmosphere for weeks ( no issues ).

My question:

* is it costing me in gas mileage ( important with gas prices ).

* I want to "fix" to get the unburnt fuel vapors back through. I believe I can use 2 hoses ( high heat resistant hydraulic hoses ) to meet up small hose, then pull the larger hose over the connection & hose clamp on.

* then at the PCV valve end put the PCV valve "in" stem & hose clamp together.

Thoughts? Ideas? Concerns??