doing the MAF

[mr.prick]

in closed loop sd my fueling is good but when i hook up the MAF to tune it,
my WOT cells are way lean.
i can`t seem to make my speed density tune match my Maf tune.
open and closed are close but not perfect and the WOT cells are good.

i have a good idea how to tune the MAF from other posts but,
i`m stumped at why i would run so lean with the MAF on and with out it i`m good.

can you tune the ve table and MAF at the same time,
so they both are in line?

i thought at WOT you fall into open loop, so if your open loop cells are good by them selves shoudn`t they be good with the MAF on?

[joecar]

You could try this:

in OLSD, log GM.DYNAIR vs GM.MAFFREQ for as much range as possible;
create a map of this to match the MAF table (only 1 column, heading is "Value", same as MAF table);
hide low count cells, select average value, enable BEN filter;
copy/paste this map into the MAF table (should curved upward and look "roundish").

Now it should be close enough to dial in using BEN's (in OLMAF).

[shallow bay]

in closed loop sd my fueling is good but when i hook up the MAF to tune it,
my WOT cells are way lean.
i can`t seem to make my speed density tune match my Maf tune.
open and closed are close but not perfect and the WOT cells are good.

i have a good idea how to tune the MAF from other posts but,
i`m stumped at why i would run so lean with the MAF on and with out it i`m good.
It sounds like you re-enabled the maf with the stock maf table. From my understanding, it will make your car run lean because the PCM will interpolate between both the MAF and VE tables.



can you tune the ve table and MAF at the same time,
so they both are in line?
I believe you can, but it won't be very accurate. I would get the VE table dialed in first and then follow joecar's advice.


i thought at WOT you fall into open loop, so if your open loop cells are good by them selves shoudn`t they be good with the MAF on?
It's actually the exact opposite. Take a look at table {B0120} RPM Threshold For Airflow Calculation. If engine speed is above that value, the PCM will use the MAF exclusively to calculate the airflow. If your MAF sensor calibration table is incorrect, then the same will be true for your WOT AFR.

[mr.prick]

You could try this:

in OLSD, log GM.DYNAIR vs GM.MAFFREQ for as much range as possible;
create a map of this to match the MAF table (only 1 column, heading is "Value", same as MAF table);
hide low count cells, select average value, enable BEN filter;
copy/paste this map into the MAF table (should curved upward and look "roundish").

Now it should be close enough to dial in using BEN's (in OLMAF).
what is open loop MAF?
how do i enable that?
do i just increase the temp that enables closed loop?
maybe thats my problem i`m trying to adjust the MAF in closed loop?

[joecar]

OLMAF = closed loop disabled (open loop, ignoring NBO2 sensors) with MAF enabled (MAF sensor contributing to fueling).

CL disabled: B3801=disable, B4205=all 284*F.
MAF enabled: C2901, C2902, C2903 set to stock values.

[mr.prick]

update:
i had to raise my stock maf values by 25% then started logging.
i have my pe mode set at 12.5 afr and have had very good luck with
adjusting the maf but the table is a little bumpy.
i`m wondering if i should have my pe set at 12.5 or not and if
i should smooth the table or not.

[joecar]

Leave the PE where it is.
When driving to log, try to keep throttle transitions smooth.
Smooth the MAF table after each BEN iteration;
BEN's get the MAF table dialed in, but a little bumpy, so just smooth it.

[mr.prick]

one more thing on this subject:
after the maf is done am i good to go back to closed loop,
or is there some other things to look at?
thanks

[joecar]

Should be good to go back to closed loop, but log it to make sure everything's ok.

[mr.prick]

LOL
btw the last log i had in open loop maf mode my v2 said i had
639 rwhp:Eyecrazy:

not likely but i think i`m about done!