Need help with SAFC II

[Drk_Drftr]

My friend just bought a 240 with a SR20, it came with a SAFC II and the car runs rich. Hes has the instructions but he doesn't know wut to set the air/fuel ratio at or wut function controls it. Help me out here.

[Silvia007]

If you don't know what you are doing, don't do anything, running a little rich is so much better then running a little lean. What kind of device does he have to tell him he's running rich?

[Drk_Drftr]

he doesn't have a device that tells him its rich, it's just shooting alot of dark smoke from the exhaust, he doesn't understand how to use it, nither do I, so if u can help that would be great.

[PMan_S13]

go to apexi's site and ask them.. they have techs that get paid to help with these type of problems

[the_Mishkin]

if its shooting dark smoke its prolly not because hes running rich. When you are rich you usually have a lighter blueish tint to it. If its black then hes most likely burning oil.

I believe you can tell the AFR from the voltage that comes off the O2 sensor. Dont quote me on that though.

[AX75F92]

The AFC II needs to be tuned ON A DYNO. Dont just start making arbitrary adjustments without knowing what you are doing. Not to mention that you are not very familiar with the unit itself. You need to find out what A/F you are running BEFORE making any changes. I would leave it alone until you can afford to have it professionally tuned. This is what they will tell you if you call A'PEX. A'PEX will not give you tuning parameters. If you would like to learn how the devise works, just for knowledge sake, you can download the instruction manual from their website http://www.apexi-usa.com, go to the "documentation" section.I wouldnt recommend using your stock O2 sensor for tuning. It is designed for emissions, not tuning. Your results with the stock sensor will be delayed and inaccurate....a stab in the dark at best. Most respectable A/F monitors come with a high grade O2 sensor. Either way, if you dont know how to tune, get it done by someone who does.Also, with black smoke you are probably correct in assuming you are running rich. You should also be able to smell the fuel. Oil will usually cause white smoke with a hint of blue.

DYNO TIME!!

[the_Mishkin]

yeah I dunno what I was thinkin. ^^^ is right.

Black smoke = rich. Blue smoke = oil. White smoke = water/coolant.

[driftaholic]

here's how it works:

the safc intercepts the mafs signal, modifies it based on throttle position and rpm, and sends the new signal to the ecu.

if you want more fuel, you make the ecu think there's more air. if you want less fuel, you make the ecu think there's less air.

tune at your own risk though, like everyone says.

[Drk_Drftr]

ok, thanks for the help

[574-240sx]

Please get a wideband to tune or tune it on the dyno. To lean it up you need to lower the correction in high and low throttle depending what you air/fuels are. Go to settings. So the number goes more negative, the bar goes further down on each of the rpm setting. I tried to explain it the best i can with you not having directions. Nick

[AX75F92]

If you think it is running rich from the last owners shade tree tuning, just set everything back to zero. This should take you back to factory fuel delivery, which shouldnt be rich if anything (Japanese ECU tuned for Japanese gas).