hey guys, here's the run down... so the other day,just after getting my car back from the shop to have a new thermowax and a cracked piece in the throttle body replaced (along with tuning the start up maps on the haltech) i was driving out with a friend behind me. the engine was around normal operating temp. I was accelerating just past 3000 rpm when the exhaust note changed to a series of loud pops/crackles. my friend, who was following behind me, said that he could hear it from his car and noticed some some along with it ( this sounded much different from backfire). i pulled over and couldn't notice anything which seemed off, except for my bov's adjuster screw was loose and the valve was running at its softest setting. i tightened it up some what and everything was fine after that. The next day the car,which just went to the shop for a high idle and was idling around 800rpm, was idling around 625 and backfiring a lot. today i checked the resistance on the BAC valve and it's reading between 1 and 2 ohms, which is what i have heard it should read. i have yet to determine whether or not the solenoid is sticking. When i disconnect the vacuum hose from my BOV the idle moves back up to 725-800 ish. i really i have no idea what to make of it. I am fairly new to rotaries and don't know a lot about the air recirculation/bypass systems used by mazda. i don't know if this helps but when i hook up the BAC valve harness the motor sounds like it has lifter tick (yes i know there are no lifters), this goes away when i disconnect it.

Sorry about the essay!
any info would be greatly appreciated.

 

Disconnect the BAC and cap it off as a troubleshooting measure.

Check the vacuum readings in the Haltech software. What vacuum is being drawn at a 800 RPM idle?

Is there noise on the CAS pickup?

 

-51.9 kPa @ 815 rpm (that's the MAP). i didn't remove the BAC though, as i had nothing to block it off with. as for noise, if you mean signal wise, i have no idea as i didn't check, but there is no audible change that I can detect.

 

problem solved!

Turns out that it was a loose connection to the leading coil. i cut out the quick connect and soldered in some wire. good as new.
also, the BAC is blocked off, and doesn't work lol.

Thanks for the help!

 

Someone used quick connect terminals to connect a standalone to your coils?

Why block off the BAC? Why doesn't it work? Is the valve bad or can the tuner just "not make it work"?

 

i'm not sure, the valve is present, just has a cap on the lower hose (the metal pipe protruding from its underside). as for the valve i have no idea, i haven't had time to check it as of yet. The cold idle wasn't working so i took it to a shop and had a thermowax and throttle wax installed, i am assuming the P.O took them out to gain greater air flow at high RPM. my mech ( a rotary specialist) informed me that the BAC didnt work nor did the mechanical idle. rather than replacing the BAC he fixed the mechanical idle. I don't mind replacing the BAC but at the moment i am unsure as to why i would. connected or disconnected it seems to make no difference. maybe you could clear that up for me?