Potential Fix for SOHC Idle problem

[atlantamx3]

Hey Guys, <p> After painting my Valve cover last week- I put a breather filter on top to replace the old hose that connected the Valve cover to the Intake Tube.<p>Since then, My MX-3 has had a much smoother idle and I do not have to "two-foot" it anymore @ the stop lights.<p>Before:
<p>After:
<p>This might be somehing a few of you want to try and see if makes any difference.<p> I picked up the Breather Filter at PepBoys for $9.99. <p>Why should this fix the problem?
~Good Question. My guess is that having the tube from the Valve cover to the intake tube promotes oil blow-by from the valve cover to go into the intake tube and therefore making the car run rich and the engine to freak out. All this oil is getting sucked back into the throttle-body or flowing down and into the MAF sensor.<p> I am probably wrong because I am not a mechanic, however.<p>Any thoughts??<p>[ July 31, 2003: Message edited by: atlantamx3 ]</p>

[atlantamx3]

Bumpity Bump.<p>Looking for feedback or ideas on this theory...<p>

[papa roached]

i would try it out, but im broke, sorry

[Genesis74]

I'll give it a try this weekend.
Did you remove the PCV valve or just add the filter to it?<p>Also, since you removed the OEM airbox and parts,
how did you attach the hood stay.<p>Thanks

[atlantamx3]

I did not mess with the PCV Valve at all-- its still in place.<p>With the Hood Prop I used a "pipe holder" bracket that I got @ Home Depot. and bolted it to the Radiator Support. Very easy and quick to do.<p> I will take a pic of it tonight so you can see.<p>*************************************************
Also-- Just an update-- I drove the car last night with the lights on and the system going and did not notice any "stalling/erratic" idle.<p> The idle is still fairly low-- but it never acted like it wanted to stall and stayed . The idle stayed right @ 750 or so at idle when I was stopped, and I had my foot on the brake.<p>I highly recommend that people try this mod-- its very cheap and may be the solution to our erratic idle.<p>[ August 01, 2003: Message edited by: atlantamx3 ]</p>

[maldo]

Another good idea is to replace and add new grounding wires. I have added several 8 guage ground wires (soon to be 4 guage) that have helped in solving the idle surge. I run wires from the MAF, tranny, head, and intake manifold to the -ve battery post. The car is poorly grounded in stock form. With these upgrades I still get the occassional idle did, mainly when I have the stereo on and my foot on the brake. Ideally, it is best to have approx. 0.30 Ohms or less of resistance at each grounding point. Currently, depending on the grounding point, resistance is between 0.67-1.56 Ohms. Another fix is to run a 30A relay to trigger the head unit directly off the battery using 8 guage wires, upgrade that ground as well as the stereo puts a lot of stress on the electrical system. Since stepping on the brake at idle tends to cause the surge as well, a time consuming fix would be to replace the +ve and -ve wires in that harness with 12 guage wires. Mazda has a tendency to use too small of a size of wire within their harnesses so it can't hurt to upgrade. The stock power wire for the fuel pump is very small. Just as an example, on the 323GT and GTX, Mazda doubled up on the power wires, running 2 instead of 1 like our car.

[atlantamx3]

Chris-- That is my very next mod.<p> I just bought some 4 Gauge wire to re-do my ground wires and to add some new ones like you did.<p> I plan on using "Gro Harlem's" tutorial that he posted a few weeks back that covers this in depth.

[papa roached]

for my hood prop holder i just drilled out the pop rivits on the stock one then screwed it into the black plate on the front

[Cryogen-X]

It works great... after about 30min of driving i stopped at the store and when i got back in and drove again it was so smooth when i stop... great mod.. shoud be added to the FAQ

[atlantamx3]

<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>great mod.. shoud be added to the FAQ <hr></blockquote><p>Cool-- I am glad it worked for someone else too.<p> I am really surprised that this post hasnt gotten a lot of attention considering that every one complains about having a low idle.<p>
It may have a similar fix on the DOHC, but I dont have one that I can look at to see.

[atlantamx3]

Anyone else try this yet??<p>I really want to see if this is the solution we have all been waitng for.

[Pearl-JapSpec]

no not yet.. soon as i fix my car i have a feeling im gonna run over to canadian tire and pick one up.

[guyaverage]

<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>I really want to see if this is the solution we have all been waitng for. <hr></blockquote><p>I'll go out on a limb, open myself for abuse and say "I doubt it". <p>My PVC is as clean as new and worked fine and I still had the idle problem.<p>Mazda will never be known for its high-quality grounding jobs, after screwing around with Rx7s for years I can attest to that. Whatever engineer was in charge of this should be shot. Upgrading/replacing/adding ground wires can only help. If you have a bazillion watt stereo, and after you installed it thats when the idle problem started, then this would probably be the smoking gun. But for the average person running stock everything, I would hinge my next paycheck that a filthy IAC valve is the culprit, not a bad ground or PVC valve. I would recommend that someone who has the infamous idle problem remove, thoroughly clean, and reinstall the IAC valve first (then readjusting the idle speed) before spending any time installing new or upgrading existing grounds or modding the PVC tubing.<p>By the way, the filter in the picture added on is filtering blow-by coming OUT of the crankcase, not filtering air going IN (it shouldnt allow any in to begin with). Eventually this is going to gunk up, clog, and not let blow-by out of the crankcase, which will foul the oil, gunk up the inside of the engine, and can even cause oil burning due to increased crankcase pressure and an even WORSE idle. Peronally, I would go back to the way you had it.<p>[ August 04, 2003: Message edited by: guyaverage ]</p>

[atlantamx3]

<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by guyaverage:
<p>I'll go out on a limb, open myself for abuse and say "I doubt it". <p>My PVC is as clean as new and worked fine and I still had the idle problem.<p>Mazda will never be known for its high-quality grounding jobs, after screwing around with Rx7s for years I can attest to that. Whatever engineer was in charge of this should be shot. Upgrading/replacing/adding ground wires can only help. If you have a bazillion watt stereo, and after you installed it thats when the idle problem started, then this would probably be the smoking gun. But for the average person running stock everything, I would hinge my next paycheck that a filthy IAC valve is the culprit, not a bad ground or PVC valve. I would recommend that someone who has the infamous idle problem remove, thoroughly clean, and reinstall the IAC valve first (then readjusting the idle speed) before spending any time installing new or upgrading existing grounds or modding the PVC tubing.<p>By the way, the filter in the picture added on is filtering blow-by coming OUT of the crankcase, not filtering air going IN (it shouldnt allow any in to begin with). Eventually this is going to gunk up, clog, and not let blow-by out of the crankcase, which will foul the oil, gunk up the inside of the engine, and can even cause oil burning due to increased crankcase pressure and an even WORSE idle. Peronally, I would go back to the way you had it.<p>[ August 04, 2003: Message edited by: guyaverage ]<hr></blockquote><p>
I want to stress again that this is NOT the PCV valve. I realize that this is for blow by coming OUT of the Valve Cover, which is perfectly fine-- I would rather it being dissipating into the air than ruining my MAF sensor with all kinds of extra oil and soaking into my air filter like it did before. As for clogging up-- It so easy to change the breather filter-- so we can just change them once a year or every 6 months. Its only $10-- but I would pay more than that for a smooth idle like I have now.<p>I plan on doing the bigger grounds very soon to help even further.

[Stan W.]

Have to agree with "Guyaverage." Most problems at idle are experienced by people who have mods or add-on electrical devices that change how the ECU "sees" the operation of the engine and the car. The ECU monitors hundreads of different combinations of voltage inputs from a variety of sensors on the engine. Add a mod and it will change the input to the sensor and the ICU. The Idle Air Control Valve/Air Bypass Valve is the most affected by engine changes "seen" by the ECU. Since the SOHC little 4-banger is tuned to get the most mileage and least emmissions, it is most sensitive at idle to any changes from factory spec. So, consider your mods to be the likely cause of a vast majority of idle problems. If you have no mods and you car is in tune, chack the Idle Air Control Valve/Air Bypass Valve.<p>Sure, I (like you guys) also wish for the long-lost days of unlimmited mods and thundering power. However, with federal emission standards and mandated fuel economy specs, thoes days have gone the way of carborated engines. <p>Stan