Did a search, nobody seems to agree on an optimum idle afr for the fd. With my initial settings my idle at 1000rpm was 11.5:1. I lowered the PIM voltage 1000rpm to about 80% and got my afr to about 13.0:1. Thats the best i could do without the engine running like crap. At 14.0:1 or above the car vibrates/runs like crap, and the ecu stumbles, cannot maintain a stable afr or idle.

I dont get it, how do I get the PFC to get 14.7:1 at idle. Ive tried adjusting just about everything, idle screw, throttle cable, inj map, etc. Any ideas? Anyone here running 14-15 afr at idle?

 

The leanest you can get a smooth idle is the best idle AFR. usually around 13:1
I think your the best you can get it and your wasteing your time trying to get leaner.

 

I've been able to get a 14:1 but that is with turning off the IAC and messing with the timing. I currently have a 13.5:1 idle with a half bridge at 1100 RPM with the IAC on. This is with 850/1600 injectors and not screwing with the lag time. I'm sure some of the lean comes from the overlap of a bridge.

 

They idle rich from the factory. Then the airpump injects air into the exhaust ports before the O2 sensor. You are asking the motor to do something that it cannot really do.

 

Yep my idle is right around 13 to 13.5. Rotarys like their fuel. You should tune idle afr to what the engine likes.

 

I have found that most modified cars prefer right around 13.0:1 for idle @ 750-800rpm. Any leaner and the idle becomes erratic and the the vacuum suffers. Cars still running the smog equipment I can get to run far leaner. As others have said tune the car where it is "happiest", don't force it to run too lean or you will have bad idle, poor vacuum and terrible throttle tip in issues.

 

Ok, because the reason I was asking is that my aem afr instructions says long periods of time of richer than 14.0:1 would reduce the sensor life. My car spends a lot of time at idle, lots of traffic, not too much freeway drving

 

Rotaries fry O2 sensors, I always keep 2 spares as backups for my Innovate wideband that I tune with. However that statement from AEM doesn't make sense, sounds like it is their easy way to not cover a warranty issue. You are really only at stoich while cruise, any performance driving is going to be richer than 14

 

the AEM wideband is a piece of ****, and the worst part is that you have no idea when it is being inaccurate unless there is an open or short circuit in the harness. I have cross-checked it with known good factory narrowbands on OBD II cars and it won't even read accurately right around stoich. I know a guy who ran the AEM with the sensor unplug (no heater basically) for hundreds of miles and the AEM never threw a code or anything. They use a GM style Bosch sensor and you can run them forever on heavily leaded race gas and they will almost never throw error codes because they have no error checking.