Idle A/F ratio questions w/ F.A.S.T.

[Jeff S]

Does it matter what A/F ratio your car runs at while idling? From what i've read on this board most people seem to think that cars idle better in open loop and with a 13.8:1 A/F ratio or richer. I've just got my car running with the F.A.S.T and it seems to idle best at around 16:1-17:1(according to my AFM Bailey WB02 (15.5+ on the dashboard display of the F.A.S.T WB02). If I add fuel to it at idle it begins to surge.

Is 16:1-17:1 ok to idle at?

 

[bruce]

Originally posted by Jeff S
Does it matter what A/F ratio your car runs at while idling? From what i've read on this board most people seem to think that cars idle better in open loop and with a 13.8:1 A/F ratio or richer. I've just got my car running with the F.A.S.T and it seems to idle best at around 16:1-17:1(according to my AFM Bailey WB02 (15.5+ on the dashboard display of the F.A.S.T WB02). If I add fuel to it at idle it begins to surge.
Is 16:1-17:1 ok to idle at?

Use what makes YOUR engine happy.
Asking for guide lines is kinda OK, but don't fall into the trap of tacking every thing others do as being the correct answer.

Reading the O2 is only one gas, and one element of what's going on. It's an indicator.

I can run my car anywhere between 13 and 15.5:1, at idle. thou, I will change the timing to match. And again we get to timing and fuel being intermixed in tuning.

 

[Craig Smith]

Bruce hit it on the head. If it works for you, it's right.

The only thing I would caution you about is that idling that lean can, in some circumstances, make it difficult to get good off-idle throttle response. Other than that I see no problem with idling as lean as you choose, provided it idles well.

 

[bigpsi94]

What relation does fuel and timing have? Say I run 13.0 at idle and if I were to lean it out to 15.0 what would I do to the timing and why? What about when the weather gets warmer or colder how is the timing affected?

 

[Jeff S]

Thanks!

 

[tubby]

ttt
i would also like the answer on that one.
thanks