o2 trims?

[goonie]

Hi guys
I have a guestion about the o2 trims
I was tuning the mid section on the maft translator,usin the full throttle tuning guide
It said that when tuning the mid section i have to watch the stft/o2 trims when i roll on the throttle from cruise to a couple of pounds of boost.
If it goes down(under 100%) the car is going rich
And if it goes up the car is leaning out
The strange thing is my car goes both ways,when i roll on the throttle to a couple of psi of boost it goes to 100% when letting go the throttle and pressing it again it goes under 100%
and also rises up to over 100%
Am i doing something wrong or what, what makes the o2 trims go both ways
Thanks.

 

[Gromit]

Hi guys
I have a guestion about the o2 trims
I was tuning the mid section on the maft translator,usin the full throttle tuning guide
It said that when tuning the mid section i have to watch the stft/o2 trims when i roll on the throttle from cruise to a couple of pounds of boost.
If it goes down(under 100%) the car is going rich
And if it goes up the car is leaning out
The strange thing is my car goes both ways,when i roll on the throttle to a couple of psi of boost it goes to 100% when letting go the throttle and pressing it again it goes under 100%
and also rises up to over 100%
Am i doing something wrong or what, what makes the o2 trims go both ways
Thanks.

On a 1G you have 3 fuel trims - Low, Mid, & Hi. The O2 Fuel Trim is what causes your Low, Mid & Hi Fuel Trims to change or set. Ideally, your Low, Mid, & Hi Fuel Trims should be close to 100% & the O2 Fuel Trim will cycle slightly above & below 100%. If the O2 Trim cycles way above or below 100%, you'll see your other fuel trims start to change correspondingly - above 100% is lean & below 100% is rich.

If you haven't already checked it out, take a gander at this tuning guide, too:

http://www.dsmtuners.com/forums/showthread.php?t=58403

 

[Quasimondo]

You're giving it too much gas when you roll on the throttle. When your O2 trim goes to 100%, that's when the ecu switches to open loop mode and no longer looks at the O2 trims.

What RPM are you cruising at, and when you're cruising what is your airflow reading? The ecu uses the LOW trims for anything below 80 Hz (approx), MID trims are 80-150 Hz (approx) and the HIGH trims are 150+ (approx). The trick is to roll the throttle and monitor what the O2 trim does when the airflow is within that 80-150 Hz window. If it goes below 100%, lean out the MID knob. If it goes above 100%, richen it up.

This guide should help out as well:
http://www.fullthrottletech.com/showthread.php?t=105

 

[timloomis]

If your o2 trim goes down then rises to 100% while your doing your part throttle,its rich.If its above 100 then drops,your lean.Like quasi said,it automatically goes to 100% at 150hz regardless.The full throttle tech link is REALLY helpfull.Its a million times better than the manual that came with the maft.

 

[goonie]

On a 1G you have 3 fuel trims - Low, Mid, & Hi. The O2 Fuel Trim is what causes your Low, Mid & Hi Fuel Trims to change or set. Ideally, your Low, Mid, & Hi Fuel Trims should be close to 100% & the O2 Fuel Trim will cycle slightly above & below 100%. If the O2 Trim cycles way above or below 100%, you'll see your other fuel trims start to change correspondingly - above 100% is lean & below 100% is rich.

If you haven't already checked it out, take a gander at this tuning guide, too:

http://www.dsmtuners.com/forums/showthread.php?t=58403

thanks this makes it easier i gues the basics are all the same, also for the maft translator?
the airflow on the mmcd logger is mafs correct?
thanks again.

 

[goonie]

You're giving it too much gas when you roll on the throttle. When your O2 trim goes to 100%, that's when the ecu switches to open loop mode and no longer looks at the O2 trims.

What RPM are you cruising at, and when you're cruising what is your airflow reading? The ecu uses the LOW trims for anything below 80 Hz (approx), MID trims are 80-150 Hz (approx) and the HIGH trims are 150+ (approx). The trick is to roll the throttle and monitor what the O2 trim does when the airflow is within that 80-150 Hz window. If it goes below 100%, lean out the MID knob. If it goes above 100%, richen it up.

This guide should help out as well:
http://www.fullthrottletech.com/showthread.php?t=105

well i wasn't logging the airflow but i will do that now thanks

 

[Gromit]

the airflow on the mmcd logger is mafs correct?

Yes, that's correct.

I'm not at all familiar with tuning via MAFT - sounds like the other link mentioned by Quasimondo should help you out with that. The concept should be basically the same.

 

[goonie]

You're giving it too much gas when you roll on the throttle. When your O2 trim goes to 100%, that's when the ecu switches to open loop mode and no longer looks at the O2 trims.

What RPM are you cruising at, and when you're cruising what is your airflow reading? The ecu uses the LOW trims for anything below 80 Hz (approx), MID trims are 80-150 Hz (approx) and the HIGH trims are 150+ (approx). The trick is to roll the throttle and monitor what the O2 trim does when the airflow is within that 80-150 Hz window. If it goes below 100%, lean out the MID knob. If it goes above 100%, richen it up.

This guide should help out as well:
http://www.fullthrottletech.com/showthread.php?t=105

when cruising the o2 trims go up and down like crazy
i cant get a steady reading on my logger
between 80 and 150 hz it goes from 0 all the way up to 136 or moore and falls back down
can this mean i have a bad o2 sensor?
is it normal that the o2 trims jump up and down like that?
when rolling the throttle i cant make a decent reading because it goes under and above 100

 

[Quasimondo]

when cruising the o2 trims go up and down like crazy
i cant get a steady reading on my logger
between 80 and 150 hz it goes from 0 all the way up to 136 or moore and falls back down
can this mean i have a bad o2 sensor?
is it normal that the o2 trims jump up and down like that?
when rolling the throttle i cant make a decent reading because it goes under and above 100

When cruising, that's what it's supposed to do. That's part of the closed-loop feedback cycle. O2 reads lean, O2 trim richens the mixture. O2 then reads rich, O2 trim leans the mixture back out. It constantly repeats itself.

Try this, instead. Note where your O2 trims cycles back and forth when cruising. That will be your reference points. When you roll the throttle, see where the high and low points are as you roll it. If those points move up, lean out the MID. If those points move down, richen it up.