L29 7.4/454 Tuning Black Box - SD tuning keeps showing lean

[motrhedx81]

I've been working on tuning my 2000 GMC L29 7.4/454 black box (BB). I know the BB is extremely simplified and limited, but I'm using the chance to play around until it the weather warms up and I can do the 0411 swap. I've been working on the speed density (VE) and every time I make an adjustment, my logs keep showing lean. I've run about 10 logs and made 6-7 adjustment tunes. It is getting better, but seems like it's making very slow progress. When I update the tune file, for the lean cells I "multiply by %", and on the rich cells I "multiply by % - half" (set up in the attached excel file), and then fill in the the gaps in the the 3D graph to make it look right (not completely smooth, but to get rid of extreme peaks and valleys and account for areas where log data isn't available).
Mod list: fresh rebuild (re-ring and bearing) with 454HO cam, mild port matching and smoothing on the heads and intake, bosch injectors, stock exh manifolds with dual original 2.75" pipe then after cats (cats hollowed out because they were broken up), change to 3" muffler and tailpipe.
*I'm running the AEM 4110 AFR gauge/sensor set, on the engine right bank.

My main question: Is it common for it to take 10-20 (or more) runs to get these in right ballpark?

Something I haven't wrapped my head around is that the AFR bounces around the target. It's gotten a little steadier as I've progressed but still bounces. Is this normal?

For those interested, below is a few logs and tunes in sequential order. Maybe you can review and provide a little feedback.

loaded this tune
2000_GMC_2500_7.4_auto_stock_tune__mod_v1.1__SD_tuning_03.hpt

ran 03 tune to get this log
2024-11-27__8__kroger_to_pisgah_home.hpl

tweaked the tune here to 05d (got kind of lost in the sauce for a bit so my log numbers got screwed up)
2000_GMC_2500_7.4_auto_stock_tune__mod_v1.1__SD_tuning_05d.hpt


ran the 05d tune and got this log
2024-11-29__1__home_to_pops.hpl

tweaked the tune here to 06
2000_GMC_2500_7.4_auto_stock_tune__mod_v1.1__SD_tuning_06.hpt

ran the 06 tune to and got these logs (connection failed mid-drive so I had to restart it and ended up with two)
2024-11-29__3a__pops_to_new_circle.hpl
2024-11-29__3b__new_circle_to_home.hpl


This is a spreadsheet I use to adjust the input tweaks for the VE table. I take the raw log and then tweak the cells that look like blip spike so I don't overshoot. (there are hidden tabs/worksheets for older updates)
2000_GMC_2500_7.4_auto_stock_tune__mod_v1.1__SD_tuning_VE_adjustments.xlsx


Also, on a fresh start, cold or warm, the AFR goes very rich and I have to hold the throttle until everything settles in. Is this something in the tune settings to get into SD mode for turning off LTFT, etc? I have some fresh start logs if interested.

[gametech]

Not being familiar with the old black box computers, I am a bit confused. The tune you posted shows STFT being disabled, but they are still active in the logs. It appears you are trying to tune via wideband, but with trims active this will never work correctly. You should really be using the narrowbands and fuel trims to tune everything outside of PE anyway. As for the restart issue, I suspect that you need to adjust how you have the MAF failed. You have the proper DTC arrangement, but you have the high and low fail frequencies at numbers that will not instantly trip a code. Just zero both the high and low MAF fail frequencies. That being said, your trims indicate they are pulling massive amounts of fuel, so if that is baked into your cold start it is probably not helping, and your base running airflow may be way off as well.

[SiriusC1024]

Fuel>Oxygen Sensors>Force Open Loop Enabled.

Tune with narrowbands, though.

What number on them Bosch injectors?

[motrhedx81]

This is my first rodeo with tuning.

injectors = Bosch 0280155884 (they're ones these engines use from Five-O motorsports)

I've wondered about STFT still doing it's thing.

Do these BBs basically force you to tune with LTFT on the narrowbands?

I'm wondering if the BB just doesn't have the right stuff for full VE tuning. I did unplug the MAF sensor to take it out of the picture. I wonder if I've taken part of the tune into the way rich territory inadvertently. I'm thinking about backing up a couple of tunes, because it generally does run better than at first, and turning everything back on to use LTFT like you mentioned.

Thanks for the feedback.

[gametech]

Whether you use ltft or stft or both, it is almost always better to tune with trims rather than the wideband in areas where you will eventually run closed loop. Sirius just showed how to turn the trims off in his last post, however, if you wish to continue with wideband only. With the trims active, your wideband errors will be minimized to the point of uselessness as the trims will be artificially keeping your fueling much closer than what the VE table is really calling for. That is why you are not getting reasonable results right now.

[SiriusC1024]

Did Five-O give a datasheet for those injectors?

[motrhedx81]

Whether you use ltft or stft or both, it is almost always better to tune with trims rather than the wideband in areas where you will eventually run closed loop. Sirius just showed how to turn the trims off in his last post, however, if you wish to continue with wideband only. With the trims active, your wideband errors will be minimized to the point of uselessness as the trims will be artificially keeping your fueling much closer than what the VE table is really calling for. That is why you are not getting reasonable results right now.

Well crap, I'm an idiot, haha. I figured after I had to keep cranking the VE table up I was screwing something up. Glad I stopped and asked.

I had wondered about that 'Fuel>Oxygen Sensors>Force Open Loop Enabled' button, but wasn't sure enough to mess with it. So, doing this would take me into true open loop and allow VE tuning on the wideband./? [statement/question].

I also see what you're talking about with the STFT pulling a truckload of fuel. I wondered and now it makes more sense. Hopefully resetting and trying your way that'll address some of the surging.

I'll do a little reset and try the VE table tuning using LTFT and STFT. I still do this with the MAF unplugged, right?

How do I set up the MAF tuning after I get the VE squared away?

Did Five-O give a datasheet for those injectors?

No, I didn't get them from Five-O (should have, but didn't). They're basically upgraded stock replacement, 19lb injector, (but 22 lb at the 58 psi of these fuel systems). Pretty common on these engines. I found a tune on this forum that used these injectors and checked mine against it; no change.

[SiriusC1024]

You don't need to unplug the MAF. Set Engine Diag>Airflow>MAF Freq Fail High and Low to 0hz. Set P0101-P0103 to MIL on First Error. This fails the MAF and forces SD.

Trans Diag>Max Line Pressure DTC's to Disabled.

Fuel>Cutoff, DFCO>Enable ECT to 248.

With MAF failed, the Secondary VE table is referenced for fueling calcs. Use the Primary axis labels to setup the histogram in scanner. Apply changes to the Primary. When done copy-with-axis to secondary.

[motrhedx81]

Ah, I see everything now. I kept wondering why I wasn't seeing the settings you were talking about (and I've seen in videos). I was just thinking it had to do with the BB tune options. I got to poking around and saw a couple of things I remembered from an intro-type video and realized I was still in 'Basic' view mode. I went into the 'Tools - Options - Editor' and switched 'Parameter View Level' to Advanced, and shazam, there they are. It's like a whole new world of possibilities, haha. (I'm mainly posting this part in case some other newby like me sees this and can use it as a reference.)

I'll get in there and start with a fresh (old/original) tune and mess with the setup. Hopefully I can get out and get some logs tomorrow evening.

What does the 'Trans Diag>Max Line Pressure DTC's to Disabled' do for the SD tuning?

Thanks again for the help.

[motrhedx81]

For the MAF tuning, after I get the SD/VE done, how do I set that up to disable the MAP?

[SiriusC1024]

What does the 'Trans Diag>Max Line Pressure DTC's to Disabled' do for the SD tuning?

If you hover the mouse over buttons a description will show at the bottom. Max line pressure is a failsafe if the MAF fails. Normal operation that's ok. Tuning SD, with P0101-P0103 purposely failed, you don't want that. It'll force full transmission line pressure.

For the MAF tuning, after I get the SD/VE done, how do I set that up to disable the MAP?

The setup for this part isn't to disable MAP and VE, it's to ignore it. Restore the SD settings except for the DFCO enable. Go to Airflow>Dynamic. Normally there'd be a High RPM disable to set to 200rpm. It's not present. So, force steady state. Hi/Lo RPM Thresh to 200rpm. Hi MAP to 103kPa. Hi TPS Delta to 100%. Zero out the VE Correction Factor column, including Initial vs ECT Zone.

To check, log Dynamic Airflow in addition to Mass Airflow. They should be identical.

[motrhedx81]

Thanks Sirius. I was able to get out and make some logs and SD tweaks using LTFT. Like gametech pointed out, this thing was set up really rich and has been pulling a lot of fuel (at least from what I can tell with my limited understanding. I've gotten the LTFTs down quite a bit but still have some work to do.

references attached, last two tune and log files

2000_GMC_2500_7.4_auto_stock_tune__mod_v1.1__SD_tuning_2-03_closedloop.hpt
2024-12-01__4__SD-2-03__pinckard_parkway_loop.hpl

2000_GMC_2500_7.4_auto_stock_tune__mod_v1.1__SD_tuning_2-04_closedloop.hpt
2024-12-01__5__SD-2-04__pinckard_downtown_kroger.hpl

To check, log Dynamic Airflow in addition to Mass Airflow. They should be identical.

I don't see Dynamic Airflow in my list of available channels to log

-----------------------------------------------------

Here is my Scanner setup for in case anybody's curious (I don't know if I had to attach all, or just the Layout file)
2000_GMC_7.4_black_box_04.Layout.xml
BB_logging_07.Channels.xml
BB_logging_11.Graphs.xml
AFR Error Ratio - BB.MathParameter.xml
charts_layout_04.Charts.xml

[SiriusC1024]

Fair bit more work to do on VE, but looks like progress.

Interesting that dynair isn't available.

[motrhedx81]

I've been able to make some more progress on the VE table, getting pretty close. Your question about dynamic airflow got me curious so I looked around.

Dynamic Airflow isn't an available channel (maybe it never was)

dyn_airflow_channel_setup.png

But curiosity got the best of me and I played around based on what you mentioned and set up a Dynamic Airflow histogram/table based on the MAF axis. I'll see what I get from this when I move over to MAF tuning.

dyn_airflow_table_setup.png

[SiriusC1024]

You'll get nothing on that histo if Dynamic Airflow isn't being logged.

[motrhedx81]

Roger that. I figured that was probably the case.

I've been just using the LTFT up to this point, and making my adjustments from that. I just watched and read a couple of things where people are using LTFT+STFT and adjusting from that. What's your take on that? Seems like that could cause some overcorrections. I also played around with a table that logs LTFT/STFT average and that looks closer to allowing good incremental adjustments.

[SiriusC1024]

LTFT+STFT until close. Do a final burn in %-half LTFT from a long run with varied driving.

[motrhedx81]

I will say one thing... this big bruiser isn't easy/cheap to feed doing all this driving around and logging, haha.

latest tune and logs from that tune attached

2000_GMC_2500_7.4_auto_stock_tune__mod_v1.1__SD_tuning_2-09_closedloop.hpt
2024-12-04__4__SD-2-09__pinckard_baptist_to_pkwy_to_home.hpl
2024-12-04__3__SD-2-09__WCHS_to_pinckard_baptist.hpl

[SiriusC1024]

You're definitely getting there. Here's a little help to speed up the process if you want.

[motrhedx81]

Thanks. I'll give it a shot. I notice you changed the 'Rich/Lean vs Airflow'. I read the description but don't completely follow. What does the tweak you made do? Also, you changed the LTFT cut-in temp. What does that improve?