nbmls1ta

I am trying to tune Part throttle and I have no idea where my a/f ratio is. My ltft's are averaging around 8-12. I know I am supposed to adjust IFR table to get them negative but I have no idea how much to adjust the table. I don't know if I am rich or lean, my O2's never settle down they switch all the time until I go WOT. How do I determine AFR from the O2's when they jump from around 900 to 65 constantly. I average them after a log and they average around 450 on both sensors. I am really confused. If I scale the IFR table by 95% that is going to make the pcm squirt less fuel which will make the mixture more lean correct? How do I know when I am too lean? What if I have to scale by 90% to get negative ltrims and I am already lean to start with? PLEASE HELP ME!! I am totally confused.
Thanks
Matt

TT_Vert

iTrader: (12)

the computer does its best to stay at around 14.6-14.7 at part throttle . the injectors are supposed to fluctuate. You only need be concerned about injector voltage at WOT. .880-.890 is where i'd wanna be naturally aspirated at WOT. Id try scalling IFR back about 5% and log again just to see how it does. You'll probally have to go back a tad more but id try .95% for now.

Dave

ataylors

iTrader: (2)

you need to get that tuning 1.0.1 spreadsheet. Email me if you want I can send it too you. It helps alot with this. You are running lean and the PCM is commanding extra fuel to make up for it that is where the postive # comes in. If you tune until the # is negitive then that means you are getting enough fuel and the PCM is commanding to take some away.

Team ZR-1

If your trims are running 12% too lean and still using the stock injectors,
forcing them to go richer by that amount will not happen overall.
You need to go with the SVO 30 injectors and tune from that.
You need to monitor the injector pulse width and assure the injectors are not running over a 80% duty cycle so that they are not being overloaded and causing PCM to jump around trying to lower the trim values on an average closer to zero.

nbmls1ta

Thanks for the help. I understand that I am lean and the PCM is adding fuel (+ltrims) but wouldn't scaling the IFR (injector flow rate) lower cause me to be even more lean or am I backwards? So you are saying once I get them negative my a/f will be ok? Lower the ltrims will not affect a/f? How do I tell if I am rich or lean? I heard to use the o2's but they fluctuate so much in part throttle they seem useless. Thanks again for the help.
Matt

SidewayzOZ

iTrader: (11)

1.0.2 is out now...make sure you use it. It has some fixes. I'm posting it up.

SidewayzOZ

iTrader: (11)

Sometimes its quite confusing. This might not be much help, but here it goes. Most people consider .900 +- 10 to be about right for AFR. If your ltrims are positive then the pcm thinks you are running lean, so therefore it adds more fuel. This causes you to be rich. Headers are a common mod that will cause this because they trick the o2 sensors into thinking there is too much air than there should be. PCM says, hey we're lean, add fuel. Then you get a rich condition. Hope that made sense.