S-AFC question

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12-27-2002, 11:44 AM

booger

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S-AFC question

ok the funny idle problem is because my car is running super rich, thats what the guy at my shop told me.

both 02 sensors are saying its running rich and he said i might have fried my hi-flow cat from bruillen b/c of it

anywho

i found an apexi S-AFC from gruppe s website for 290 free shipping (i found it for 399 from isr LOL)

anyway, if i get it can i tune it without a A/F gauge? does the AFC tell me where in the rpm my car runs rich or does it just tune>?

thanks BANSUVs in advance=)

oh and BTW, if you have a 99 and plan on or have an aftermarket intake, i strongly suggest getting an AFC so you dont have the headaches im having right now

Last edited by booger; 12-27-2002 at 12:07 PM.

12-27-2002, 08:11 PM

Kevin M

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Car Info: 1993/2000/2001 GF4 mostly red

Are you running stock O2 sensors again? I still think they may be incorrectly calibrated (or the dweeb at Pep Boys or wherever gave you the wrong one) but yeah, running rich is bad for the cat. And yes, an S-AFC would probably enable you to lean it out- but be very very very careful and patient, running even slightly to lean (like say 14.5:1 instead of 14:1 for example) could start you a-pingin', and that is death to your motor.

And you're welcome as always

12-28-2002, 04:43 PM

booger

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no im not changing any parts on my car till i get the S-AFC on and tuned. however i dont think you understand what i was asking..
i know u use the AFC to tune the AF ratio , however i was wondering if it is gona tell me where in the rpms im running rich in the same way a AF ratio gauge does. meaning will i be able to tune the AFC w/o a AF gauge.

12-28-2002, 10:01 PM

Kevin M

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I haven't a clue, as I don't have any experience with the AFCs. But why skimp on guages? Get an EGT, A/F, and oil pressure guage as soon as you can. It may save you big money down the line.

12-28-2002, 10:45 PM

Shin RS

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Car Info: MkIII MR2, s14, 94 mx5, 99 mx5. The beauty of rwd.

It won't tell you your A/F ratio, but since yours is a '99 it will show you the air that is consumed by the intake. ('00s and 01's show manifold air pressure)

Get the A/F ratiometer, if not if you could get a hold of a wideband A/F meter, it would be way more accurate than the narrow band stock a/f.

Stay on the rich side... it's safer for your engine...

12-28-2002, 11:33 PM

booger

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any idea why my car would be running so rich in the first place? i have an intake so shouldnt it be running lean? or is it lean and the ecu is overcompenating making it rich?

12-29-2002, 01:07 AM

Kevin M

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Something is convincing the ECU that it's either getting more air than it actually is, or getting less fuel than it actually is. Lots of things that can cause that. Typically though, it's O2 or MAF related. Coule also be a difference in fuel pressure or your injectors sticking open.

01-06-2003, 03:31 PM

DoMeAgainDon

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best and only way to tune your afc as well as your richness problem would be on a dyno..i had to do the same thing. You'll never be able to do it your self with a a/f guage, you have a better chance of damming a river 1 rock at a time.
I took mine to www.bmtranny.com