Potential Fix for SOHC Idle problem

[Mackey]

Just wanted to let ya know i did this modification and my idle seems to be much more stable. Before it would jump from 500 to 1000 all the time and would sometimes bog when i went to accelerate. Now it stays at 750 all the time and runs well.

[Ryencool]

i have this idle prob and I dont have any mods really, and exhaust and lowering springs, i higly doubt those put load on the elec system...ill be trying this mod shortly

[Curtis]

ive done this to my mazda,and it works fine but, maybe it just me. it spits out some oil on my valve cover thats the only thing that sucks! No,its not because its loose,or not on right
(ive been through 2 of them) i just got to wipe it of with a rag, every now and then. my friend was telling me its doing that because its sitting on top. well thats just my problem. im pretty sure it happens to all that have it on top?? i might be wrong?

[guyaverage]

If the idle problem cleared up and using and occasionally replacing the filter setup is ok for you, I say great and go for it, problem solved. More importantly, I think you hit on what exactly is causing the idle problem for most of us.<p>When I cleaned my IAC valve for the first time, I also had a lot of oil in the intake tube. Not enough to soak the filter, but enough to make me wonder. I personally believe the cause of the infamous idle problem is the oil. Oil is getting past the PCV valve, lightly coating the innards of the intake tract, and over time the combination of the oil, blowby gases, ambient moisture, normal intake tract carbon, and whatever particulates getting past the air filter are forming a thin layer of gunk in the IAC valve, restricting airflow, and kaboom, now you have your idle problem. Readjusting the idle alone will take care of the problem for a while, then it just comes back.<p>I cleaned my IAC the first time about 6 months or so ago in a fit of pissed-off rage trying to find this problem. Its been a great summer, the first one in 9 years where I can sit in rush hour traffic and not have my teeth chatter as the idle drops to 200, up to 750, back to 200, up to 750, and on and on every time I dare step on the brake. I had my first “almost stall” the other day, the first time this entire summer. I figure the oil and gunk have built up again, time to clean it. If taking a half-hour every six months or so is all I have to do to keep this monster at bay, no problem. Half hour to remove the IAC valve and intake hose, clean it out, reinstall it, pull the battery cable and reset the ECU, reconnect battery, jump #10 to ground, readjust the idle, shut her off, done. <p>I’ve never removed the valve cover from my 1.6, is the PCV valve shielded or baffled from the valves on this engine? If not, it needs to be. If it already is, then its a bad design. The amount of oil getting past the PCV valve on this engine (at least mine) is way more than I have seen on my Honda 1.8. I pulled the valve cover off it, its got a pretty elaborate baffle in it, I pulled the tube off its PCV valve and there is hardly any oil at all in it. My Mx3 tube is soaked.

[ltjrunner]

that could be the case...i know with my intake out i noticed heavy "gunk" in my intake tube and now i have a solid metal pipe(still not my complete intake but, im lazy and sick of this engine) and idle seems to stay a lot better. and i actually did put a breather on yesterday, car felt fine and idle wasnt a problem untill i was speeding and had to jump on the break. idle only dropped to like 400 so i wasnt worried.
ill keep you guys posted on it. hopefully we eventually can get this damn idle issue fixed as much as we can so we no longer have to worry about the car stalling in traffic or after we get off the highway. <p>also, you might want to clean out the inside of the maf. i got mine as good as i could with out taking it a part but im debating taking it a part and cleaning the intake track so who knows, we could be getting closer to a fix. good luck to anyone else trying to figure something out.

[jaydog5678]

Perry ya may not like what I have to say, but the PCV system is there for a purpose. I'm not messing with you guys, but just trying to get some fact across the board. <p> No piston ring, new or old, can provide a perfect seal btwn the piston and the cylinder wall. When an engine is running, the pressure of combustion forces the piston down. This same pressure also forces gases and unburned fuel from the combustion chamber past the rings and into the crankcase (crankcase vapors). These combustion byproducts, particularly unburned hydrocarbons, form blowby. The crankcase on modern engines cannot be ventilated directly to the atmosphere, because of the hydrocarbon vapors add to the air pollution. <p> When intake air flows freely, the PCV system will function right, as long as the PCV valve is not clogged. Modern engine design includes the air and vapor flow as a calibrated part of the air-fuel mixture. Some engines see as much as 30 percent of their idle through the PCV system.<p>I honestly don't believe that putting the crankcase breather solve's the problem, but simply alleviates it. Excessive blowby was the case with you Perry. I've seen how bad the intake tract, and filter looked. They were soaked with oil. Worn piston rings or cyl. walls may be the problem. It's possible the previous owner just neclected the PCV valve and the frequent oil change. When the PCV system begins to clogg, the engine tends to stall, idle roughly, or even overheat. You may have leaned out some of the mixture at idle causing it to rise because of non-existant crankcase vapors in the intake. Remember that these are unburned hydrocarbons in the crankcase that were designed to be reburned in the combustion chamber.

[atlantamx3]

Justin, <p> You are and always will be DA MAN!<p>You know me & my MX-3 better than anyone. <p> <p> <blockquote><font size="1" face="Verdana, Arial">quote:</font><hr> I honestly don't believe that putting the crankcase breather solve's the problem, but simply alleviates it. <hr></blockquote><p>Thats good enough for me right now. As long as she idles smooth and doesn't embarass me @ the stoplights tryin to stall out-- its all gravy.<p>One of these days when I get lots of $$-- I am doing the BP swap which should solve everything... but until then-- the $10 crankcase breather is just fine for me.-- That is, unless another better solution comes my way!<p>

[Genesis74]

Would it be possible to install some sort of inline filter? I know they make them for fluids but I am not sure about gases.
Would that filter out the oil only and not the gases or would it filter out both?
Perhaps that would keep our intakes clean while retaining the recirculating function of the system?<p>Just an idea

[illLusionschic18]

atlanta you are my hero, my car has been idlein really stupid, i put the breather filter on yesterday and it idles so much more smoothly. thanx for the idea!

[Seanthepizzadude65065]

I have a differant idea, i changed my 02 sensor on my car and it made a huge differance, i had more power plus the idle thing was gone. Im going to try this filter thing too to see if i notice a differance

[papa roached]

i just threw a breathere on there, the idle seems more sure of itself<p><p>[ August 17, 2003: Message edited by: papa roached ]</p>

[maniac]

would a small fuel filter work better? I've heard of that being done on pcv valves to keep everything cleaner and to know how much oil is actually getting out. would it work for this application?

[papa roached]

hmmm, interesting idea, i think any with a slip joint would work

[CosTauD]

I've bought a filter just like yours (I've got the idle problem as well) but it just get worst. When I give it some gaz my car stall right after. Did you put something where the tube is? Darn this car is really getting on my nerves :p

[papa roached]

i used electrical tape to seal it up