25% ltft

[KCG]

Sorry Joe, missed your reply. Yes my fault on the reverse coil wiring bank 2. No more popping. After 5 years I guess I was just too excited hearing it fire off right away to realize it really wasn't running smoothly.
Figured out the YELLOW gas was what the 93 octane here looks like.

Now part 2...

LTFT still at 25%. STFT ~10-12%. Working on the phone with my tuner and emailing logs and tunes, a lightbulb went off in his head. Trims adding 30-35% and my LS3 injectors being 30-35% larger than LS1, he sent a me a tune with LS1 injector data. Loaded and immediately change to trims. Much closer to zero. But why?
He feels the air the MAF is reporting makes sense and commanded afr is 14.63. I've went over this thing multiple times for unmetered air. Can't find any.

1 - MAF sensor reading incorrectly? bought used
2 - O2 sensors reading incorrectly? both new with first start

edit:
Been reading stickies...Could I follow this procedure to disable MAF and see what trims do?
Would the results tell me if my MAF is reading correctly or not?

A. C2901: MAF High Frequency Fail 1: Change to 1 Hz
B. C2903: MAF High Frequency Fail Limit: Change to 1
C. Copy B5913 High-Octane Spark to B5914 Low-Octane Spark
D. Insure MAF Sensor Circuit is displayed as a current DTC

[joecar]

Sorry Joe, missed your reply. Yes my fault on the reverse coil wiring bank 2. No more popping. After 5 years I guess I was just too excited hearing it fire off right away to realize it really wasn't running smoothly

No worries... I got so many projects in all different directions... yes, it's always exciting when you fire it up after putting it all back together

Figured out the YELLOW gas was what the 93 octane here looks like.

where are you located...?

LTFT still at 25%. STFT ~10-12%. Working on the phone with my tuner and emailing logs and tunes, a lightbulb went off in his head. Trims adding 30-35% and my LS3 injectors being 30-35% larger than LS1, he sent a me a tune with LS1 injector data. Loaded and immediately change to trims. Much closer to zero. But why?

Sounds like he edited the IFR table to match the larger injectors you have, so now the ECM opens the injectors for shorter period, so now your trims went down.

He feels the air the MAF is reporting makes sense and commanded afr is 14.63. I've went over this thing multiple times for unmetered air. Can't find any.

1 - MAF sensor reading incorrectly? bought used
2 - O2 sensors reading incorrectly? both new with first start

Post pics of engine bay showing MAF plumbing.
Does your MAF have the honeycomb screen (which is an airflow straightener)...?
Post some logs, I can eyeball MAF wrt other pids to determine if it is correct.

edit:
Been reading stickies...Could I follow this procedure to disable MAF and see what trims do?
Would the results tell me if my MAF is reading correctly or not?

A. C2901: MAF High Frequency Fail 1: Change to 1 Hz
B. C2903: MAF High Frequency Fail Limit: Change to 1
C. Copy B5913 High-Octane Spark to B5914 Low-Octane Spark
D. Insure MAF Sensor Circuit is displayed as a current DTC

This would cause the PCM to run from the VVE/VE tables rather than the MAF, it would check how close VVE/VE is modelling air (i.e. if trims are not close to zero, then there is room for correction).

[KCG]

No worries... I got so many projects in all different directions... yes, it's always exciting when you fire it up after putting it all back together

where are you located...?

Maryland

Sounds like he edited the IFR table to match the larger injectors you have, so now the ECM opens the injectors for shorter period, so now your trims went down.

Yes, numbers were ~5.x, now ~3.5

Post pics of engine bay showing MAF plumbing.

Does your MAF have the honeycomb screen (which is an airflow straightener)...?

I think what you're referring to looks like this.. and mine is NOT like this

Post some logs, I can eyeball MAF wrt other pids to determine if it is correct.

ok cool. Heres basically before & after the data change, EDIT: they're AFTER, then BEFORE.

This would cause the PCM to run from the VVE/VE tables rather than the MAF, it would check how close VVE/VE is modelling air (i.e. if trims are not close to zero, then there is room for correction).

I was looking at this as a way to test if the MAF is reporting correct data. I thought if its DISABLED, and my trims go somewhere other than with ENABLED MAF, then that would tell its reporting wrong. And the reason LS1 data has band-aided it even tho they're LS3 injectors. Did I explain clearly?

[joecar]

There is a 90 degree bend in plumbing immediately after the MAF... oin this bend, most of the airflow is on the outside, this skews/distorts the airflow that the sensor sees.

[joecar]

...
I was looking at this as a way to test if the MAF is reporting correct data. I thought if its DISABLED, and my trims go somewhere other than with ENABLED MAF, then that would tell its reporting wrong.

That would work, as long as the VE was close.

And the reason LS1 data has band-aided it even tho they're LS3 injectors. Did I explain clearly?

Sorry, I'm not following you on this sentence (I just ran out of coffee)...?

[joecar]

From your logs, your MAF is reading low.

[KCG]

There is a 90 degree bend in plumbing immediately after the MAF... oin this bend, most of the airflow is on the outside, this skews/distorts the airflow that the sensor sees.

How much of a straight section is recommended on the output side?

[KCG]

That would work, as long as the VE was close.

Sorry, I'm not following you on this sentence (I just ran out of coffee)...?

I'm just trying to say since the injector data has been changed to create acceptable trims, this says something is wrong. Whether its the MAF, O2 sensors or possibly the injectors themselves.

From your logs, your MAF is reading low.

ok, reading low...from the 90 degree discussed above or faulty MAF?

[joecar]

I'm just trying to say since the injector data has been changed to create acceptable trims, this says something is wrong. Whether its the MAF, O2 sensors or possibly the injectors themselves.


ok, reading low...from the 90 degree discussed above or faulty MAF?

From the bend being so close to the MAF sensor (the bulk of the air travels on the outside of the bend, starting from about 6-8 inches before the bend (because the airflow has to be continuous, i.e. it cannot have any discontinuities/steps), this causes the sensor to see less air as oriented in your pic.

[KCG]

ok, am I thinking this correctly...
The ECM thinks there is LESS air going into the engine. In other words, there's MORE air going in, the ECM doesn't know about.
So with O2 feedback trying to maintain commanded 14.63, it reads this additional air and therefore tells the ECM we need more fuel to maintain stoich?
That's why my trims were going so positive?