Y2KevSE

iTrader: (13)

Mine seems to stay at about 14.4 until I go WOT, then it drops down to the 11's (rich) and fluctuates until I let off.

Is the Tomei suppose to sweep back and forth during normal driving?

Jane and I had fun tuning the S-AFC with the Tomei yesterday. The A/F is around 13 now (a bit lean for boost applications).

Thanks for any info.

Y2KevSE

iTrader: (13)

By constantly, I mean does it fluctuate around 14.7 (not like the Autometer gauge where the lights go back and forth off the range of the gauge).

delio

iTrader: (11)

Contact Confused he was complaining yesterday that the guage doesn't sweep enough. He may be of more assistance.

Y2KevSE

iTrader: (13)

Hopefully Brett or Jeff (CalsonicSE) will see this. I saw Jeff's gauge and I think it swept a bit when he reved the car.

theblue

you do understand that a stock O2 sensor hes three settings - rich, lean, and normal. This means that the sensor can only work so well and it will sweap as it goes from rich to lean.

Y2KevSE

iTrader: (13)

The stock O2 was replaced with the Tomei O2. O2's product voltage from 0-1 V (0 side = lean, 1 side = rich), so they don't have just three settings (infinite within the 0-1 range).

matt calder

iTrader: (2)

Sounds cool kevin, keep me updated

Keven97SE

It should do that. Like theblue said, under normal (cruising...ie throttle position below 40%), the ECU runs in closed loop mode, alternating between slightly lean and slightly rich. It should only go rich and stay there under heavy throttle (over 40%).

Keven97SE

One more thing, Kev: Please let us all know how the tuning goes. I really would like to know whether or not the 40% throttle S-AFC tuning trick indeed works by bypassing the ECU self-learning and allowing the car to keep the modified A/F settings. Good luck!

Y2KevSE

iTrader: (13)

OK



Yes, but the needle doesn't sweep at all in closed loop mode. I figured it should at least sweep inbetween the high 13's or mid 15 range during normal driving (including accel and decel).


I tried looking at my scan tool to see when the car goes into open loop, and it seems to happen at around 42%. The only problem with the OBD-2 scan tool is that the readings aren't in real time (slight delay), so I don't think I'm getting a very accurate reading.

The A/F is about 13 now, so we'll see if it dips back into the 11's again.

wdave

They all work the same - 0-1v dc according to mixture. The response curve is almost vertical around 14.4 so the computer sees it as more of a switching function - over or under. The computer them changes the mixture up and down to compensate. Depending on the response time and damping of the meter it will sweep under steady state throttle - big sweeps with fast response and smaller sweeps with slow response.

Y2KevSE

iTrader: (13)

Hmmmmm..... could be the meter or the amp thingy connecting to it that minimizes the fluctuation.

Thanks.

CalsonicSE

iTrader: (3)

When I say rich, I mean anything below stoich. When I say lean, I mean anything above stoich.


Freeway speeds w/cruise control on - the Tomei will for the most part stay around 14.4 but will sometimes slightly fluctuate (i.e. jump to 14.0 and quickly jump back to 14.4)

Driving at lower speeds w/o cruise control - the needle will definitely fluctuate more between rich and stoich (a/f may even jump to 11.0:1 if I suddenly give the accelerator a good tap) depending on how much throttle response but it always goes back to about 14.4 or whatever.

Freeway offramp - I completely let off the gas, and the needle will fall to lean and go back to stoich as my speed/RPM decreases. This only happens after I've been driving on the freeway and then let off the gas. If I let off the gas at lower speeds, the needle will just go to stoich.

WOT - The needle will jump to rich and steadily rise without any fluctuations as my RPMs rise.

Stopped at a traffic light - The needle will sometimes fluctuate between rich and stoich.

Cruising down the twisty hill to my house in 2nd gear w/o pressing accelerator (engine braking) - It will stay at about 14.4 and not fluctuate at all.

Confused

iTrader: (4)

Mine just looks at me, smiles and says, "I loooooove boost daddy".

delio

iTrader: (11)

you freak... Nice job of dusting me on the Cross Island last night... Pheer the CRX... If you hadn't of launched the way you did I woulda ate you for lunch...and then.... I WOKE UP

sx7r

iTrader: (15)

must not work the same as the greddy a/f gauge.

CalsonicSE

iTrader: (3)

How does the GReddy operate?

sx7r

iTrader: (15)

14.6 when just driving normally. goes to 16.0 on decel in gear.

Y2KevSE

iTrader: (13)

Thanks for the insight, Jeff. I went WOT on the freeway today for about 10 seconds or so and quickly let off the gas. The needle fell to about 16.0 and went back to stoich when the car decelerated to about 80 mph.

Looks like I experience what you experience (to a certain extent).

Y2KevSE

iTrader: (13)

Is that after a WOT run or just anytime you decel?

Y2KevSE

iTrader: (13)

Have you convinced Hogan to give you his Tomei so you can install it on your other bank?

sx7r

iTrader: (15)

anytime i decel.

matt calder

iTrader: (2)

Hey Thomas, the greddy comes with its own O2 sensor right. Its pretty much the same thing as the tomei but cheaper?? How hard was it to hook up, I am thinking about getting the greddy because it is cheaper than the tomei. Thanks
matt

Y2KevSE

iTrader: (13)

I see. Wonder what the differences (performance-wise) are between the two gauges.

Thanks.

sx7r

iTrader: (15)

yeah, it has it's own O2 sensor. cheaper? how much is the tomei?

Y2KevSE

iTrader: (13)

$100 more than the GReddy.

CalsonicSE

iTrader: (3)

When coasting/decelerating on the freeway, the needle will go to the lean side & go back to stoich as you decelerate. How lean depends on certain conditions.

Kev, you said when you go WOT, your a/f will jump to rich and fluctuate as your RPMs rise?? Shouldn't the rise be steady and not fluctuate?

On another note, I just used 14.4 as a reference point in this thread. Depending on the driving condition, sometimes it may be 14.2, 14.3, or whatever.

Our minor differences would also be explained by our mods, fuel management (setting/condition of FPR, anything) , etc. Not every car is exactly the same. Also, 4th gens and 5th gens should have different fuel maps in the ECU. Not to metion that the condition of our OEM O2 sensors will have a affect on fuel during closed loop operation.

irvine78

iTrader: (2)

well, my autometer air/fuel sweeps constantly from lean to rich...
and when i drop the hammer on my gas pedal, it goes all the way to rich..although the guages are made by different company, i think it still works in the same way..

Y2KevSE

iTrader: (13)

My needle doesn't move at all (accel or decel) unless I go WOT.

When I go WOT, the a/f gets richer and richer and stops at about 12 (I've adjusted the AFC settings a bit so it's not 13 anymore). The needle doesn't fluctuate... the moment is steady.

Y2KevSE

iTrader: (13)

Want a cookie, Hoon?

sx7r

iTrader: (15)

here:

Y2KevSE

iTrader: (13)

Thanks for lending your cookie, Thomas.

sx7r

iTrader: (15)

anytime, got a full jar.