Variable Resistor?
 

What is this thing and where is it have to be set.Any pics i need to reset mine.

I read your post wrong, I'm an idiot. Mine was in the middle if that helps.

If I were you, I would check out the rtek 2.0 ecu upgrade. It provides most of the functionality of a standalone and is plug and play. The price is only $400, so about $800 less than a standalone system. Check out their site for the S4 NA:

http://www.pocketlogger.com/index.ph...age=2&ecu=S4NA

Josh

The idle richness screw--variable resistor? It's located by the air box. Little turn thing that has an L and R on it. Why do you need to replace it?

The variable resistor adjusts you idle air fuel mix. When your car is idleing at its normal 750 and all the way warmed up jump the initial set coupler and then go over to the variable screw, put it in the middle, and slowly turn it counter clockwise (lean) until its starts to die down a little and stutter then turn it clockwise (rich) until the engine RPMs go up and it idles fine. What you will be doing is adjusting your air fuel ratio for the idle so you are gunna want to get it as level and clean as possible.

Ok so it only adjusts it at idle? Im gonna make sure mine is set up right.

Hey
 

Can i just set in to wear i feel the idle is best at that ratio?Because i dont know were the stock idle fuel ratio has to be set.

I tried to adjust mine earlier today and after I let it warm up I started to slowly turn it to the left (counterclock wise) and I turned it all the way and nothing happened. My idle didnt change one bit. Could it be broken?

my a/f is 9 and my screw doesnt do jack crap either. my idle is kinda choppy too.. i think my thingie went out also :(

Your thingie? U mean the variable resistor? Im trying to see if I can find out how to check to see if its working or not. I haven't found anything yet.

I seem to remember there is a "pill" in the vacuum line to the sensor unit. perhaps the line was replaced without salvaging the "pill"?

Ramses666

100% Correct. Also can double check this information against the FSM (just gives the same instruction with the added detail of what the tach should read while you're doing it)
Yes. It only adjusts the lambda at idle. If you're eyes burn from the exhaust then you're probably running a little too rich.

Your question makes no sense. Are you asking about the lambda ratio? Follow the FSM and you don't even need to worry about the Lambda.
Yes, it could very well be broken. You're working on a 20 year old car. Alot of the electronics need repair and service. If you're exhaust is running rich then you're more than likely in fail-safe mode (read, puts the idle richness to max). What you can do is call up Mazda and order a new Variable resistor, or if you feel so inclined you can go to radio shack or your local electronics store and buy a radial potentiometer (however you spell it).

However before you do any of that, disconnect it from the harness, and bring it to your multimeter. You can test it by attaching the multimeter to it and turning it back and forth and look at the resistence. It should be linear from one side to the other. If there's any dead spots, or parts where it reads 0Ohms or Max Ohms out of place then your Resistor is fubbared.

If you'd like to do the radio shack thing save the plug and just cut it enough away from the busted resistor to allow the new resistor to be soldered in its place. Pretty straight forward.

What do you mean choppy idle? you have a pulsating or an idle that oscilates between two specific RPM? If that's the case then you may have something else wrong besides a Variable Resistor. More than likely you have a vacuum leak. You can use propane to isolate that and repair or replace the line or gasket that is leaking. Other possibilities would be a TPS (Throttle position sensor) that is out of adjustment, which I would check first. You can use a multimeter for that. Do a search for the appropriate directions here on the forum. It's honestly covered about once a week. After that's been checked and resolved we'll look at your variable resistor.
See above comments on how to check.
What pill? The variable resistor is not connected to vacuum. Are you referencing the Pressure Sensor? You must be as that's the only vac line I can think of near the Variable Resistor that has a pill in it. That too might be responsible for the oscilating idle of fc3schick87, however I'd be more inclined to think the TPS is out of adjustment or dead.

Yes I was confusing the pressure sensor with the idle control screw potentiometer. However this could be an issue if all vacuum lines were replaced and the little inline "pill" was deleted. I apologize for my error.

Ramses666

Thanks a lot lax-rotor. You have been a gigantic help. Im gonna test it tomorrow.

Very true. Honest mistake. You're usually right on the money on most of your posts from what I remember.

NP

I'm still learning every day. I'm not an "expert" by any means.... just bored with nothing else to do. Trying to help.

Ramses666