redrocket1

iTrader: (32)

Hello everyone i have searched for a breakdown of the IACV removal and haven't been able to figure it out with the PFC. (my idle surges from 1k-2k after its warm then gently settles down after a few minutes. I tried to disconnect my IACV and the car just stalls . Before i disconnect it what do i need to do to my car and PFC to make the idle tune able. Do i start the car with it disconnected? Please iam all ears.


Separate question that i haven't been able to find was what should the stock boost settings be set at. Both the bar (psi divided by half) and the duty cycle? (stock twins and no fuel upgrades).

Thanks.

redrocket1

iTrader: (32)

Ignore the boost settings question. I found it finally adjust the boost so you dont get fuel cut and play with the duty cycle until you have found your boost setting.

arghx

iTrader: (3)

There is no silver bullet for a stable idle. When you remove the ISC you trade one set of headaches (surging usually) for potentially another set (rough idle and stalling). It comes down to proper tuning (with working sensors) and a properly adjusted TB, whether you have an ISC or not.

I really think that removing the ISC is a last resort, having dealt with one car that has it removed and one car that does not. When you remove it, yes you can run more idle timing (if you have a datalogit and know what you're doing). You are giving up though the extra air supplied when you have the A/C or accessories running, the extra air supplied when you pop in the clutch to prevent stalling, and a somewhat adjustable idle speed through the commander (once you have it tuned right).

you may have a problem that is not related to the ISC itself at all, like a misadjusted TPS. Set the TPS to proper spec. Then tighten the screw under the TB elbow (between the two lower studs) all the way in, and back it out 1/4 - 1/2 turn. Reset the PFC and do the idle learn procedure from the PFC manual with O2 feedback off (unless you still have an airpump, then keep it on). Then you need a wideband and will have to tune the car until your idle AFR is somewhere between 12.5:1 - 13.5:1 , usually on the richer side if you are ported.

Do all those things first before you go removing equipment that Mazda installed on your vehicle for a very good reason. I have found that even though you can't adjust the idle timing (any adjustments to the map are ignored by the PFC) with the ISC installed and enabled, the idle feedback system can still keep the idle stable if you have everything set up right.