SAFC leaned out but im still running really rich??

Atari007 · 11-24-2002, 03:06 PM

ok guys, i know that this has been beaten to death, and i just saw another post that was kinda what i was looking for, but not exactly... First off my relavent mods are: Big16G, SAFC, 550s, HKS 264/272, Walbro255, 3" Turboback... and I do NOT have a AFPR...
well, I seem to be running really rich... In a 3rd gear pull @ 6k rpms, my EGT is showing 1450*... and my blue wire is reading .96-.97 @ WOT.. isnt this really really rich?? here are my Hi AFC settings:

1k -22, 2k -24, 3k -24, 4k -23, 5k -21, 5.5k -19, 6k -18, 7k -17

This just seems like really low setting and i want some reassurance before i keep leaning it out... am i missing something? Should I keep leaning it out? My car just seems more sluggish then it should be.... And no, I dont have any type of logger... and because of christmas I wont be able to get one untill a good bit into next year.... Help!

Thanx guys--

PS: No black smoke out of the exhaust and checking the plugs isnt going to matter since Ive been changing my settings so much lately...

larryd · 11-24-2002, 08:43 PM

First off , how much boost are you running with these settings.. Running 10lbs or 20lbs makes a hell of a difference..

without a logger its really hard to tell exactly what the car is doing timing wise but if your EGT shows you being rich and your o2 is reading that high then yes keep leaning it out. -21% isnt all that much.

when I had my Big28 and denso 190 pump I was at -25% across the band on the S-AFC and that felt good at 20lbs of boost. Thats a smaller pump then you meaning Id assume you should lean the car out even more then me.

Atari007 · 11-25-2002, 07:24 AM

Oh yeah, I forgot to mention that I am running 16psi! I guess that is pretty important!! :o and Ill go and lean it out more this afternoon... I just wanted to make sure that Im not going too low on this!

TSi92 · 11-25-2002, 10:58 AM

Check for leaks. A boost leak will make your car run rich no matter how much you lean out the S-AFC.

Faded · 11-29-2002, 12:54 PM

FYI - I'm @ 18psi and my S-AFC High settings are:

-19% 1K
-18% 2K
-26% 3K
-34% 4K
-42% 5K
-44% 6K
-44% 7K
-44% 7.5k

You still can lean it out more. I hit 885C on the EGT with .90 O2 @ 21+ timing.

44pirate · 11-29-2002, 10:59 PM

Lean it out more. I run 21 psi at -26 across the board at the track on race gas. Pummp gas I run 18psi at -24 across the board.
Didn't you have another thread about this?

DSMJim · 11-30-2002, 07:26 AM

Hold on a second. I thought until about 2 seconds ago the lower your 02 reading the richer you were. It's an oxygen sensor, the more fuel you have the lower the oxygen content is so you will get lower reading when there is less oxygen and more fuel present in your exhaust system.

Somebody please correct me if I am wrong here...

SPEEDY · 11-30-2002, 09:19 AM

Quote:

Originally posted by DSMJim
Hold on a second. I thought until about 2 seconds ago the lower your 02 reading the richer you were. It's an oxygen sensor, the more fuel you have the lower the oxygen content is so you will get lower reading when there is less oxygen and more fuel present in your exhaust system.

Somebody please correct me if I am wrong here...

The higher your O2's are reading, the more richer you will be running.

Faded · 11-30-2002, 09:41 AM

Quote:

Originally posted by DSMJim
Hold on a second. I thought until about 2 seconds ago the lower your 02 reading the richer you were. It's an oxygen sensor, the more fuel you have the lower the oxygen content is so you will get lower reading when there is less oxygen and more fuel present in your exhaust system.

Somebody please correct me if I am wrong here...

The lower it is the leaner you are. I want to say that Stoic is .80-.9something. Does anybody have the break down chart off hand? I know that .96+ is pig rich for my car.

On a 2G STFT and LTFT the higher it is the richer you are. Maybe that is what your thinking of?

DSMJim · 11-30-2002, 11:36 AM

ok guess im just smokin something...

2-0turbo · 12-01-2002, 03:58 PM

Quote:

Originally posted by Faded

The lower it is the leaner you are. I want to say that Stoic is .80-.9something. Does anybody have the break down chart off hand? I know that .96+ is pig rich for my car.

On a 2G STFT and LTFT the higher it is the richer you are. Maybe that is what your thinking of?

Actually, stoich is between 0-1 volts. That is how a narrow-band O2 works. A sharp change in voltage at the stoichiometric. Individual voltage readings don't really mean too much. That is why they suck for steady state readings.

They work well for a control system that will constantly oscillate back and forth over the setpoint (stoich), but are not very useful for steady state. That is why your O2 voltage oscillates up/down while in closed-loop (during idle, less than 4K RPM and less than 25% throttle). Your computer is "hunting" back and forth over the setpoint (stoich).