Well I finally got my Idle to calm down, got it to stop bouncing by adjusting the TPS using the LED method and also adjusting the throttle cable. Now it just idles slightly high. Around 1200 to 1500, it changes in that range though it doesn't bounce anymore. Also, I did a volt meter check on my BAC valve and it said 12.7, I know spec is up to 12.3. So anyway, I have tried to change the Idle speed by the screw in the BAC and it is tightened all the way down, still high Idle though. So my question is.... Do I need a new BAC valve? Ifso, where do I get one... I checked MAZDATRIX and couldn't find one.. Also wondering if someone who has removed it has one laying around for sale...
Thanx!

 

Sounds like a TII. Its a vac leak btw. Oh, and the ECU fuel cuts at 0% throttle at 1500rpm. So if a vac leak was causing a raising idle, the ecu would fuel cut around 1500, bring it back down, give fuel back, and the vac leak would again cause rpms go up. You probably just "fixed" the problem by calibrating your intake set to cope with the unmetered-air vac leak (specificaly by closing the BAC/Idle adjust, throttle cable.)

You fixed it the wrong way, and you won't get idle down unless you find that vac leak. Then you'll have to go undo your vac-leak-idle-calibration, as once the vac leak is capped/fixed, you will probably have an idle of like 400rpms, if it runs at all. It probably won't-- though I've gotten my n/a to get idle low enough where you could physicaly count the exhaust pulses.

 

Since YOU think its the bac, instead of going out and buying one used or new, make sure it is the bac.

Do this. Go to the autostore. Ask where they're gasket making paper is. Buy some for two bucks. Take your bac off. Lay it on the paper. Make an outline. Cut the outline out. Make two holes and two holes only in the paper to match the bac attach bolt/screws. Install the paoer gasket then the bac over it.

Now there is NO possibility of air getting past the bac. Start the car. Is the idle down now??? If so....it was the bac. If not.....look elsewhere.

If it was the bac, buy some carb cleaner. Install the bac harness on the bac with the bac out of the engine. Lay it hole facing up. Spray the carb cleaner in it. Turn the ingition key to ON ONLY. The bac should vibrate and work the cleaner around. Do this to your hearts content. Then reinstall the bac and see if it helped.

 

you're full of tricks like this aren't you?

 

Sounds great! I'll get right to it, thanx guys!

 

Hello, I have just installed my Greddy TD06 turbo into my TII, took out the air pump and ACV (if that makes a difference) but now my idle is around 1500.... sometimes it goes down to 750, but most of the time it rests at 1500....... I clamped every vac hose i took out, and others that i didn't need i put caps on it so it should be OK right? =) do you guys think it can be the same problem? a vac leak causing my idle to rise? Should i check my BAC gasket? or just adjust the idle **** thingy?

 

What if (and this is what my TII does), you start it, and it idles at 900, then once it warms up, begins pulsing and idling at 1200-1500?

sorry to highjack your thread.

 

mind the fuel cut at 1500, check for vac leaks.

as for cold idle... my car doesn't idle when its cold at all... and it is set properly, but not thermal wax