Pavetim

iTrader: (15)

I keep chasing my AFR. Heres what I want. For idle which is 600rpm and between 35-40Kpa I want 15.5AFR, for cruise between 30-45Kpa I want 15.5AFR, for 50-65Kpa I want 14.7AFR and 70kpa and above i'm enabling my PE. I keep going back and for when I make the appropriate chages my VE table looks so bad, but then when I smooth it throws it off again? Somebody recommend what to do I will email you my VE table and my innovate log. Thanks a bunch guys.

Black02SS

iTrader: (36)

Don't smooth it as much. Depending on the mods your VE table might not turn out perfectly smooth. Just get the peaks and ridges tame.

ringram

In order to get those afr's you must be running open loop. If not the pcm and o2 sensors will be fighting you and it will never be right.

Pavetim

iTrader: (15)

I am running open loop with the MAF disconnected. I think i'll understand this a little more if there is another table to adjust idle AFR seperate from the VE table, is there such a table? Oh and to calculate AFR for PE. Say my WOt afr is 13.5 and I want 12.6 what do I put in the PE table? Thanks.

SSpdDmon

iTrader: (10)

There's an OLFA (open loop fuel air) table that will control your AFR if you're running open loop. This works for all conditions except where PE is enabled. When PE is enabled, the PCM will take the "richer" value from either the OLFA or PE table.

Ideally, the computer thinks the VE table is the base for it's fueling structure. It assumes all of the values in the VE table (when plugged in to an internal equation) will net a stoichiometric AFR, which for our cars is told to be 14.63. The OLFA table then says, "If the VE=14.63, divide that by the numbers in my table to be used as a commanded AFR." Keep in mind I say commanded AFR because there is no feed back from the O2 sensors in the exhaust to help correct the AFR and fuel trims are turned off. PE acts the same way, but only under certain conditions like high loads on the motor or "x" % throttle. If you want to target a 15.5 AFR for idling conditions, you'll need to make the appropriate changes in the OLFA table. Hope that helps some. G/L!


**HINT** When tuning with a wideband O2, set the entire PE table to an EQ ratio of 1.0 and the entire OLFA table to a safe EQ ratio (ie 1.13) to dial in the VE table. By doing this while tuning in open loop, your commanded AFR should always be 13.0 (don't forget to turn off cat over-temp protection). Then, you can determine your correction to the VE table by dividing the observed AFR by the commanded AFR. (Example observed=9.0 and commanded=10.0, then 9.0/10.0=90% which translates to a 10% reduction when multiplied to the VE table value for that cell.)