Bank 2, too lean

[S54B32]

My ltfts typically sit near 8-10 on each bank, have for years, and I have never gotten any sort of lean code/warning. Interesting.

Unless you are 100% stock, you can’t compare this to another one.
And also depends how you drive/load rpm areas etc..
I assume you have a tune? When WOT is programmed very rich, this will not get you in trouble. But if you already have petty „lean“ WOT and you have very low LTFT, then chance is high your combustion temperatures are not that great and on track use or high speed runs you could make some damage..
If you have not a tune, I would check injectors/filter/pump.


Just my opinion: if someone has a tune and is not interested into fine tune the load load/cruising areas or fuel consumption and so on, I would at least recommend to turn off the fuel adaption or restrict it, that WOT is safe.

[S54B32]

1.00= means 100% fuel
0.90= means 90% fuel (or ~10% less fuel than table)
1.10= means 110% fuel (or ~10% more fuel than table)

so in easy speaking it means the ecu multiply the calculated fuel from table (and other factors) with this factor and then outputs this to the injectors pulsewidth.

[sapote]

I have to disagree, near 10% less fuel can indeed cause a lean condition. Especially with a (canned?) tune, I suggest to contact your tuner (HTE), because with 8 and 9% LTFT .

Wait, so LTFT=0.91 in ECUworx means 9%? For me it's either 0.9% or 91%. How do you get 9%?

[ATB88]

My ltfts typically sit near 8-10 on each bank, have for years, and I have never gotten any sort of lean code/warning. Interesting.

[S54B32]

If you have all present, log the wideband over serial port and load/rpm etc with testo, buy a megalog viewer HD license and you quickly will find you rich spots in the map.

[eacmen]

I would recommend getting a wideband gauge with min/max feature to take the guess work out of it.

[Cubieman]

I have to disagree, near 10% less fuel can indeed cause a lean condition. Especially with a (canned?) tune, I suggest to contact your tuner (HTE), because with 8 and 9% LTFT your map has rich spots where the ECU adapts the fuel down and multiplicate this trim also on WOT events where o2 correction is not active. In my opinion 2-3% fuel correction is okay, but not near 10% on a narrowband dme controlled engine!

btw do you have your WBO2 on bank one or bank two? Or do you have dual channel WBO2? Sometimes a injectors starts clogging and cause lean conditions on one bank, but as you the both fuel trims relative bad, I don’t think this is the case.

The wideband is only on bank 2, I'll have to reach out to HTE and see what he thinks after I send a few logs as this car was dyno tuned with all the current modifications.

[S54B32]

The ECUWORx tool shows STFT2=-0.03 and LTFT2=0.91
These number seem to be so small and should not cause a lean code. If ECUworx has STFT in ms of pulse width then without knowing the table or calculated injector pulse width then giving STFT in ms makes no sense as we have no idea what percentage 0.03ms is from the calculated pulse width.
And if both STFT and LTFT are in percentage, then these value cannot cause a lean code as they are too small.

I have to disagree, near 10% less fuel can indeed cause a lean condition. Especially with a (canned?) tune, I suggest to contact your tuner (HTE), because with 8 and 9% LTFT your map has rich spots where the ECU adapts the fuel down and multiplicate this trim also on WOT events where o2 correction is not active. In my opinion 2-3% fuel correction is okay, but not near 10% on a narrowband dme controlled engine!

btw do you have your WBO2 on bank one or bank two? Or do you have dual channel WBO2? Sometimes a injectors starts clogging and cause lean conditions on one bank, but as you the both fuel trims relative bad, I don’t think this is the case.

[sapote]

FWIW here's a snapshot of the fuel trims etc. after some somewhat spirited driving around town last night for about 45min.

The ECUWORx tool shows STFT2=-0.03 and LTFT2=0.91
These number seem to be so small and should not cause a lean code. If ECUworx has STFT in ms of pulse width then without knowing the table or calculated injector pulse width then giving STFT in ms makes no sense as we have no idea what percentage 0.03ms is from the calculated pulse width.
And if both STFT and LTFT are in percentage, then these value cannot cause a lean code as they are too small.

[Cubieman]

FWIW here's a snapshot of the fuel trims etc. after some somewhat spirited driving around town last night for about 45min.

I'll post a log when I have some more time, thanks for the help!

[Cubieman]

Post a warm idle log with LTFT and STFT. I don't know if the DME can output calculated air mass rate as you have MAP instead of MAF now.

Using Testo last night I could not help but notice that I could live data from the "MAF" sensor, currently I have my IAT plugged into the MAF sensor connector with an adapter so maybe it's reading the IAT, not sure.

I'll use the ECUworx tool to look at Long and Short term fuel trims and do some logging when I get a chance.

Having a lean condition isn't something I want...not so great.

[sapote]

Post a warm idle log with LTFT and STFT. I don't know if the DME can output calculated air mass rate as you have MAP instead of MAF now.

[Cubieman]

Do you log min/max on your wideband while on track?

I did not, I use a laptop/testo to get that info and never having any real issues with the car before I haven't had a reason to log.
Next track day may be on the 20th so I'll be logging data for sure then.

It may be tune related, I don't know of course, it's interesting it didn't show up on track.

We left the track, I topped off the tank (just over a Qtr.), hit the interstate and within 10mi of driving the SES came on, was cleared and didn't come back.

[eacmen]

Ok, so this is not in reference to the pre-cat O2's? I figured it was, I believe I have my post cat O2's "deleted" but I'll have to double check.

I drove around town last night with my WB O2 and it seemed OK (hovering around 14.7), but yesterday was a track day and only my 2nd, so the engine saw different conditions than usual. However the first time I had it on the track this issue did not arise.

Do you log min/max on your wideband while on track?

[repoman89]

Ok, so this is not in reference to the pre-cat O2's? I figured it was, I believe I have my post cat O2's "deleted" but I'll have to double check.

I drove around town last night with my WB O2 and it seemed OK (hovering around 14.7), but yesterday was a track day and only my 2nd, so the engine saw different conditions than usual. However the first time I had it on the track this issue did not arise.

Ugh my bad! Ignore me. Got my codes mixed up, I was thinking P0420.

What do your adaptations/fuel trims look like?