Hey every1,
Once again my idle problem has returned. It magically went away for 4 months, but now it came back. Basically what happens, is the idle will bounce between 1500-2000rpms, if you blip the throttle it will fall to 850 but immediately come back up and start bouncing again. THEN if you apply any electrical load (a/c or lights), it will raise the range to 2000-2500 and bounce. I removed my AWS system last time and that seemed to cure it. I tried unplugging the ISC and after a while and a few throttle blips it stopped bouncing, but remained at 1700rpms. Thats when i thought it could just be stuck open (the idle screw is all the way out), but once again when u turn the lights on, the idle raises again to 2700rpms but now holds.... Any ideas how to fix this? I might be able to locate a ISC locally and test a different one out...but i dont think its the problem because the idle still raises on any electrical load.....it just boggles my mind though because i cant think of any other electrical system that controls idle. I checked all the hoses and vac lines as well, none have popped off or begun to leak.

Any ideas/suggestions would be appreciated.

-Zach

 

The only other thing i can think of is that Airpump solenoid....i might get in there and just take it out, since i have no vac lines running to it anyway and hi-flo cats dont necessarily need the airpump...could that affect idle?

 

^bump^ anyone??

 

I don't believe that affects idle. Have you checked the Factory Service manual?

 

im going out to read it now, but off the top of my head the only things taht could possibly affect idle are:
ISC
AWS
Wax rod assembly
fast idle screw
*possibly* the airpump solenoid

 

Well, i just decided to gung-ho it...removed and blocked off ISC, removed and blocked off airpump control valve, removed the wax rod assembly and re-routed the coolant line. Adjusted idle to a clean 900 RPM with the fast idle screw and all is well!

-Zach

 

My idle had similar symptoms. I unplugged my air pump, and the symptoms improved dramatically. However, my car was diagnosed with a faulty Air Control Valve. I have the parts, but I haven't swapped it in yet.

 

Zach,

I was counting on you to solve my idle and turbo glowing problems. I think you're on the right track with the ISC. On page F236 of the service manual. It states that if the ISC circuit is shorted, the valve will always be fully open, causing high idle speed. ( After warm-up engine hunts at approx. 1,500 rpm). I believe I have a spare ISC sitting around, if you want try it out

 

sounds like a plan. I've got no plans on Sunday, lemme know if u wanna get 2gether and see if we cant fix some stuff.

 

didn't read carefully enough...thought I read you were going to block off...didn't realize you had actually did it ....I couldn't find an ISC only an AWS and ACV...when you blocked those solenoids off, did you use resistors?

congrats on fixing it

 

The ISC is on the back-drivers side of the UIM. The part # mazda has for it is 20-660. And yes, i did block all of them off, and i jsut deal with the check engine light. You can use resistors to eliminate that problem though.