vx idleing to fast

[GasSavers_Ryland]

I've never been able to get my vx to idle at 600rpm like it's suposed to, best I can do is about 900rpm, in an effert to fix this problem I pulled the guts out of my PCV valve (had tossed the stock empty elbo years ago thinking it was the worng part) and sudenly my car wouldn't idle below 1,500rpm (fully warmed up) no matter what I did with the idle adjustment screw on top of the throttle body, it will idle faster, but not slower, I pulled the hose that lets fresh filtered air in to the top of the valve cover, and you could feel a strong vaccum, as it built up vaccum you could see the RPM drop (I have a digital tiny tac installed under the hood) I ended up stuffing some air filter foam in the empty PCV elbow so that it wouldn't suck so much air in, as that seems to be part of why it's idleing fast, but that restriction meens that it's not pulling in the gasses that it's suposed to.
It would appear that I have to much air seeping in to my crank case, but I can't figure out where, or how.
I've already replaced the valve cover gasket, and the rubber seats under the valve cover studs, the oil fill cap seal also looks perfect.
all of my vaccum hoses are in good shape, I have a new throttle body, I have a new PCV hose, gromet and connections (hoses under the intake manifold) so I'm not really sure what else I should be checking.
the car has 246,000 miles on it, 195psi compression and 0w30 synthetic oil.

[jadziasman]

Three possibilities:

1) EACV (idle air control valve) is faulty.

2) ECM is faulty.

3) Vacuum leak somewhere. Unmetered air is entering the intake and increasing the idle.

I would guess the last one.

[Danronian]

I would remove the IACV on the back of the intake manifold, and clean out the ports with some throttle body cleaner. Chances are, it is clogged.

Make sure there isn't too much tension on the throttle cable.

Also giving the motor a Sea Foam treatment (into the intake manifold) couldn't hurt. I know it fixed my idle so that it goes down to 400 RPM sometimes like it should.

After this, I would suspect there could be something wrong with the TPS. You can test it to make sure it's reading correctly with the Honda Shop Repair Manual.

[GasSavers_bobski]

Eh. So you have an empty elbow for a PCV valve? That would be #3 - you have a vacuum leak in the form of a gutted PCV valve.
The PCV system is supposed to constantly pull crankcase vapors into the intake manifold to be burned, rather than let them escape into the atmosphere. The PCV valve is there to let that happen without causing a huge vacuum leak.
Fresh air is drawn in through that tube between the corner of the valve cover and the air filter tube. Covering that breather tube prevents any additional air from entering the crankcase, at which point the idling engine will draw the crankcase pressure down to manifold vacuum if you let it.

Go get a new PCV valve and a can of carburetor cleaner. Install the valve. Start the engine and spray the cleaner around the various hoses and seams where air could be leaking into the manifold. If the engine bogs or stutters, you've got a leak there.

[Danronian]

Originally Posted by bobski

Eh. So you have an empty elbow for a PCV valve? That would be #3 - you have a vacuum leak in the form of a gutted PCV valve.
The PCV system is supposed to constantly pull crankcase vapors into the intake manifold to be burned, rather than let them escape into the atmosphere. The PCV valve is there to let that happen without causing a huge vacuum leak.
Fresh air is drawn in through that tube between the corner of the valve cover and the air filter tube. Covering that breather tube prevents any additional air from entering the crankcase, at which point the idling engine will draw the crankcase pressure down to manifold vacuum if you let it.

Go get a new PCV valve and a can of carburetor cleaner. Install the valve. Start the engine and spray the cleaner around the various hoses and seams where air could be leaking into the manifold. If the engine bogs or stutters, you've got a leak there.

Nope. The VX has a non-traditional PCV valve that is only a plastic elbow from the factory. Mine came that way, as did my friends VX motor and they both idle just fine and get great MPG.

[DarbyWalters]

You can use WD40 and spray around the outside of your intake ect. and listen for drops in rpm. That will help find most leaks...the rpm will drop when the WD40 finds a entry.

[GasSavers_bobski]

Originally Posted by Danronian

The VX has a non-traditional PCV valve that is only a plastic elbow from the factory.

The factory service manual lumps all the models together when it comes to the PCV system, meaning they all have the same basic design. In addition, Majestic (an online Honda parts dealer) lists the same part number for the VX PCV valve as the one for the EX, which I can personally confirm is not an empty elbow.
VX page, #6: link
EX page, #6: link

[Danronian]

Then why would so many VX motors come from the factory with the empty style PCV valves? What Honda carries now doesn't always mean that's the parts they have always had.

Actually I checked out the links you posted with the parts numbers.

On the VX, only one PCV valve is listed, wheras on the EX, two different numbers are listed. One is the VX one, the other the EX... Looks like the VX has a different one to me.

Then on the CX, only the non-VX one is listed: http://www.hondaautomotiveparts.com/...EATHER+CHAMBER

And the DX has both listed like the EX: http://www.hondaautomotiveparts.com/...EATHER+CHAMBER

I still would guess the VX one is different for a reason since I've personally seen it in VX motors that were all original looking.

This is a picture of my "empty elbow" one that came on my low-mile VX motor when I bought it. Same one I saw was in my friends VX motor.

[GasSavers_James]

Mine's a low mile vx with mostly original parts and it has the empty elbow. Also it idles just fine, usually around 550-600, just a hair above that little first line on the tach, but will go up around 1000 when the lights and fan etc are on.

[Danronian]

Originally Posted by James

Mine's a low mile vx with mostly original parts and it has the empty elbow. Also it idles just fine, usually around 550-600, just a hair above that little first line on the tach, but will go up around 1000 when the lights and fan etc are on.

Same as mine, though my high idle is around 900.