Thread: What Air/Fuel ratios do you see at idle?

yea my air fuel ratios goes from lean to richening right off the bat. its just kinda annoying becuase with my AAC valve plugged in my air fuel ratios are 16.x-17.x and it makes my idle somewhat rough.

then when i unplug my AAC valve and i adjust the idle screw the air fuel ratios go down into the stoich and it smoothes out my idle.

i see around 11.x when under 100% load maybe low 11s to mid

AT Idle, it should read 14.7 give or take. Anything over 15.5 or so it will start to get rough.

At WOT, most try to get it at 11.5 not to exceed 12.

From what I understand 14.7 is what the Factory ECU is set at.
11.5 is where people try to get it so they motor won't blow. More fuel at WOT isn't good either.

well my car is fully tuned and its on a more rich con servative tune for what the motor is. but for some odd reason my air fuel ratios like to be at the more lean (rough) part at idle which drives me crazy cos stoich sounds so much better.

my problem is i have a macbook and my aem ems runs off windows so i have been lazy and havent installed windows on my macbook to run bootcamp and i also need to get a serial to usb port adapter to run to my macbook also so i can go in and look at my system at idle

Well, soon as you get that AEM up and running on u'r laptop take a look at you A/F and just change it...
Let me know how it all works out.

In the morning mine was rich, then slowly leans out to 14ish (from memory)...

yea i really need to tap into the aem and look at it, i kinda like the way the engine sounds at 17.x with the 3'' side exit, its real aggressive i think if my idle was lower it wouldnt be that bad but my idle is like 1400rpm and so it kinda gets annoying

I installed the AEM wideband finally, with the GTIR, and a huge leak from the vacuum manifold, it reads off the scale, (over 18) at idle, quite rough. At WOT, it reads somewhere between 10 and 12.

i dont think that the highe air fuel ratios matter at idle, but the thing is the idle will be more rough, i have hks camshafts and having the idle rough becuase of the air fuel ratios and then the camshafts on top of that the idle just sounds real rough and the exhaust sounds really aggressive, lik i said it wouldnt be bad if it was around stoich, but i am going to have to do some adjusting.

today i cleaned the AAC valve,pcv valve, sprayed some carb cleaner in the IACV hose and have yet to see if that effects my idle any...need to get it down from 140rpm

back to back to back to back post.

Next time, please just edit your 1st post if you come up with anymore questions or thoughts.

Thanks

what I'm being taught at Nashville Auto Deisel College is you want 14.7 at idle and cruising to keep a happy median with emissions and power. But 13.1 has more power potential but fuel economy drops. I wish I could show you our graphs but oh well. Calum told me to tune the Car at 14.7 AFR idle and 14.7AFR @ 3000 rpm cruise then fine tweak it after that.