I have a new ported motor in which they forgot to tune for the idle. Its driving me crazy and I would like to go ahead and fix it myself, however I am not sure what A/F ratio I should tune the car to when it rests at idle.

Anyone know?

 

14.7...or close that is what widebad indicates

 

About 14.0 to 1 or as lean as you can go and still have a smooth idle.

 

mine used to idle at 12.2 but it was running way way rich then, now my car idles at 13.5 which seems to be a pretty good ratio, still have smooth idle and my exhaust isn't too fummy

 

The consistent smooth idle limit for my street port is 14:1.

 

I was getting good idle at over 18:1 on a stock motor with bolt ons. Now I have a fluctuaing idle that rises and drops a few hundred rpm as rhythmic as a metronome.

 

If you have a PowerFC, be aware that injector lag settings can result in problems with tuning the idle mixture. You can make the lag smaller to gain more control over the idle mixture, but then you need to richen up the whole map a little bit to replace the amount of injector open time that was lost when ou reduced the lag. If you just reduce the lag to get a good idle mixture without richening up the rest of the map, the car will probably stall as soon as you try to move. Search for more info.

-Max