Soccerking3000

Okay i have a 93 si with a d16z6, it was running fine, did the valve lash and it now stumbles at idle all the way to around 3k. If i hold it at 2500 rpm it will dip slightly then go back up, this happens every 2 seconds or so, i checked my valve lash and everything is in order, could it be that i am running lean and that is causing it to stumble? I have the right level of oil and coolant, and i bled the coolant to make sure no air bubbles were in the system. Any help would be appreciate, thanks guys. ohh and i have a small amount of white smoke when i drive, its cold out out and its not bad but,i'm not sure if its more than what it should be

Soccerking3000

bump

Silvabullet

hm.. wats a valve lash..

jaydmegsix

there is a adjustment valve on the throttle body you have to use a flathead screw driver to adjust it. do you have any vac leaks or any check engine.

let me know if that works

Archidictus

Intake air control valve. It's the bottom half of your throttle body and they go bad all the time. Replace it and I'm sure your problem will magically go away.

LorenGeist

Awesome, I'm going to have to check mine, I have had the same problem for some time now.

EeKk^

I had the same promblem and it was the idle control valve which sits on the rear part of the intake manifold

92 CIVIC HATCH VX

possible o2 sensor problem

Archidictus

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EeKk^ &raquo;</TD></TR><TR><TD CLASS="quote">I had the same promblem and it was the idle control valve which sits on the rear part of the intake manifold</TD></TR></TABLE>

I'm actually talking about the valve that sits on the bottom of a D-series throttle body and meters air intake at cold idle. It's possible that I'm calling it the wrong thing. Just look at your TB. The valve I speak of has coolant lines coming from it in two places. It's 3 10mm bolts to get it off.

Soccerking3000

well i ahve no check engine lights, or vacuum leaks, timing is good, and its on the bottom of the throttle body? i will look at it tomorrow morning, thanks guys ohh and do both of these valves on the back and the bottom need to be replaced or just cleaned with like carb cleaner or whatever?

DAguyLS

i thought everyone who ever own'd a d-series knew about the idle air goin bad.....huh....guess not

spdweb.net

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Archidictus &raquo;</TD></TR><TR><TD CLASS="quote">

I'm actually talking about the valve that sits on the bottom of a D-series throttle body and meters air intake at cold idle. It's possible that I'm calling it the wrong thing. Just look at your TB. The valve I speak of has coolant lines coming from it in two places. It's 3 10mm bolts to get it off.</TD></TR></TABLE>

The IAC which I THINK you are talking about is difference between different models.. some are on the bottom of the TB (Barrel type valve) others are on the back of the Intake Mani (Slide type valve). Contrary to some posts in this topic.. they rairly go bad.. instead they mostly just get dirty and can be easily cleaned.

You said this happened right after you set your valve lash? You mean valve clearence check correct? Between the rocker arm and valve or rocker and cam on some models. I would tend to think this would be the cause if thats when it happend. You may want to check if your doing it right. If your valves are too tight they can stay open when the car warms up.. This would cause low compression.. and over time.. very very bad stuff!!!

DAguyLS

yeah i bet you know more than Archidictus

laughs

DAguyLS

and actually civic's are notorious for having the aicV go bad

get your facts straight before you post

spdweb.net

Really that's not true, the IAC works by simple magnetic control. They fail mechanically because of dirty conditions. Most of the time cleaning brings them right back to life.. however.. that is not the point of this entire topic.

You said it stumbles all the way to 3k.. that would have nothing to do with the IAC since the ECU abandons use of the IAC as soon as it gets a reading from the TPS. I also thought of one more thing to check. Your plug wires... You obviously removed them to take off the valve cover. I recently had the same problem myself after removing mine. Specially on carbon wires which are really susceptible to being damaged by disturbance. I would suggest first ohming out your plug wires with a multi meter to see if they have good conductivity. If not, you can get a random miss fire and stumble when you step on the gas.

92 CIVIC HATCH VX

yeah mine was stumbling real hard earlier this year i have to replace the coil pack and that fixed.

FizzGiGG

OK, yeah, Archidictus MUST know everything while the rest of the planet does not.

I would have to agree with spdweb on this one, the IACV (not aicV) loses out to the tps once on the gas. Do a little test here slamdLScivic... Remove one of your plug wires and let us know how it runs, I bet it stumbles like Soccerking3000's does.

Dink.

FizzGiGG

BTW - Archidictus, I am not by any means going after you on this one, just pointing out that slamdLScivic must be humpin your leg or something...

tripwire1212000

I would check the plug wires as well, never rule out that the coil may just be getting weak and it might be time to change it?

FizzGiGG

My experience has shown me that coils don't get old or weak, they either work or they don't. Could be wrong though.

ABK

the bottom vavle thing is a fast idle warm up valve or someshit like that.

the one on the intake matifold that faces towards the wirewall is called an IAC (idle air control).

But something tells me that you prolly unhooked couple vacume lines.

I think you've done your valve lash when you installed your cam so you know what you are doing, so I don't think that's your problem.

I would suggest unplugging the IAC, and if that doesn't help take a propane torch (don't lite it) but just spray propane all over your engine bay. If the engine stumbles almost dies then you got a leak where you are spraying at.

FizzGiGG

IACV = Idle Air Control Valve

No such thing as a High Idle Warm Up valve, the idle air control valve has a coolant line going to it, so when the car is cold, the IACV knows it. When the vehicle warms up, it knows it. So the IACV takes care of increasing the idle when cold, and once it warms up it will lower the idle back down.

Now be done with the terminology already and wait for the dude to check a few things out.

ABK

Okay whatever you say

the bottom thing got coolant lines going thru it is to provide more air for the warm up. Once the coolant gets warm it closes off.

IACV is operated by computer it's not a mechanical valve. It's a solenoid that's comptrolled by ECU to compensate for load conditions. For example if you AC or powersteering or alternator (or anything else) creates a load condition on the engine it prevents the car from dying at idle by letting more air go thru to the IM.

Don't lecture me on this stuff.

ABK

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by FizzGiGG &raquo;</TD></TR><TR><TD CLASS="quote">My experience has shown me that coils don't get old or weak, they either work or they don't. Could be wrong though.</TD></TR></TABLE>

yes you are wrong buddy. They short out individual windings

spdweb.net

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ABK &raquo;</TD></TR><TR><TD CLASS="quote">the bottom thing got coolant lines going thru it is to provide more air for the warm up. Once the coolant gets warm it closes off.

IACV is operated by computer it's not a mechanical valve. It's a solenoid that's comptrolled by ECU to compensate for load conditions. For example if you AC or powersteering or alternator (or anything else) creates a load condition on the engine it prevents the car from dying at idle by letting more air go thru to the IM.

Don't lecture me on this stuff.</TD></TR></TABLE>

Look.. this topic has gotten WAY 'off topic' and its really getting on my nerves. You are talking about two different types of IAC valves. On z6 cars and some Y8's the valve is a slide type valve as show below. Yes, coolent does run through the bottom of the TB, then ALSO to the IAC valve which is located on the back of the manifold. This is a slide type valve. There is NO valve in the bottom of the TB on this type of setup. The coolent lines only pass through there to keep the TB from iceing up in very cold temps. They do then travel to the slide type IAC valve which remains open while the car is cold by way of a mechanical thermostat.



This second type IAC valve IS on the bottom of the TB.. there is NO slide type valve on these models ALL 96-00 DX Y7 motors and automatic Y8's. On this setup, the coolent travels into the IAC which remains open while the car is cold also by a mechanical thermostat. It ALSO keeps the TB from freezing since it is hooked to the TB itself. They are both IAC valves.. They both stay open mechanically when its cold... just two different types. I say again, if you have the slide type valve, there is no other valve in the bottom of the TB.. the coolent flows in, and right back out only to provide warmth.



If you want to take it one step farther.. I dont even have coolent running to my IAC, it's capped off at the manifold. The ECU alone on obd2 cars is smart enough to hold the IAC valve open just by use of the IAT ( Intake air temp) sensor.

I did a section on this in my z6 intake swap article..
http://www.spdweb.net/index.ph...id=64
Read up!

IN CONCLUSION.. Fizz is right.. there is no high idle valve thingy.. its the SAME THING! It's all done by the IAC valve, mechanically (cold) computer (warm).


NOW.. Check the plug wires and ignition.. thats what it is if your sure you did the internals right.