It is an interpolation like you say.
My recommendation is to run it and pull a data log. We'll let the feedback data tell us where the values need to be changed.
Progress Thread finally tuning (and more)
- Thread starter JD1964
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It is an interpolation like you say.
My recommendation is to run it and pull a data log. We'll let the feedback data tell us where the values need to be changed.
You kidding? He googled that sht!
Seriously, I've seen what he worked with, near genius level and fears nothing, he was copilot when I crashed his toy chopper, didn't flinch, just said like "whoops, not good"
I did 3 different datalogs. These are NA, not boosted (yet).
60 degrees ambient temperature.
1. Startup from cold and idle until warmup.
2. Gentle cruise with a few gentle gearshifts.
3. Full throttle 3rd and most of 4th. (had enough roadway but was gaining on traffic and had to let off before the top of 4th)
trying to upload these .csv files and the forum wont accept them
60 degrees ambient temperature.
1. Startup from cold and idle until warmup.
2. Gentle cruise with a few gentle gearshifts.
3. Full throttle 3rd and most of 4th. (had enough roadway but was gaining on traffic and had to let off before the top of 4th)
trying to upload these .csv files and the forum wont accept them
Just me but if you have not I would do the following:
1) Have the injectors professionally cleaned. I have a set of Lightning 42 lb/hr injectors and they were down to 39 lb/hr and the spray pattern was not good.
2) install a dedicated 12 ga power wire and relay for the fuel pump. Use the old power wire (after the inertia switch) to trigger the new relay.
3) If you can swing it upgrade the fuel lines to 6AN as well as the fuel pump hanger.
This made a difference with my NA 331.
1) Have the injectors professionally cleaned. I have a set of Lightning 42 lb/hr injectors and they were down to 39 lb/hr and the spray pattern was not good.
2) install a dedicated 12 ga power wire and relay for the fuel pump. Use the old power wire (after the inertia switch) to trigger the new relay.
3) If you can swing it upgrade the fuel lines to 6AN as well as the fuel pump hanger.
This made a difference with my NA 331.
The injectors I got from a performance service and were claimed to be refurbished and ready and they dont have much time on them.
I like your idea about upgrading the power wire to the pump. (on the list now)
There are a lot of channels that are not recorded in your data logs:
A few specific corrections:
| Exact tag | Description in his definition |
|---|---|
N | RPM |
LOAD | Load Actual |
LOADX | Load% |
TP | Throttle Position Sensor |
TS | Throttle Status (CT/PT/WOT) |
MPH | Vehicle Speed Sensor - MPH |
SPARK | Spark Advance |
ACT | Air Charge Temp |
ECT | Engine Coolant Temp |
BAP | BARO Sensor |
VBAT | Battery Voltage |
VMAF | MAF in Volts (corrected) |
IMAF | MAF in Volts (uncorrected) |
MAF | MAF in Kg/hr |
EVP | EGR Valve Position—his wideband input |
LAMBSE1 | LAMBSE - PS |
LAMBSE2 | LAMBSE - DS |
KAMRF1 | KAMRF - PS |
KAMRF2 | KAMRF - DS |
HEGO1 | HEGO Sensor - PS |
HEGO2 | HEGO Sensor - DS |
PW1 | Injector Pulsewidth - PS |
PW2 | Injector Pulsewidth - DS |
FLAGS1 | FLAGS1—includes OL, bit 2 |
FLAGS4 | FLAGS4—includes DFSO, bit 1 |
FLAGS10 | FLAGS10—includes WRMEGO, bit 2 |
DSDRPM | Desired RPM |
ISCDTY | Idle Speed Control Duty Cycle |
ISCFLG | Idle Speed Control Flag |
AEFUEL | Accel Enrichment Fuel |
EFTRFF | Transient Enrichment Fuel |
ATMR1 | Time Since Start |
TUNEPOS | Tune Position |
A few specific corrections:
- Use N, not N_BYTE. The latter stops reporting increases above 4,080 rpm.
- The MAF entry has inconsistent labeling: its description says kg/hr, but its Units field says lb/min. Preserve the export’s units/header so we interpret it correctly.
I think ET shows up automatically because I never selected it as a parameter but it shows up in all the logs. I have edited the log payload to include all of the parameters you listed above. The count is 33 but that doesnt include ET. So, 34 parameters includung ET should be displayed on playback for the future logs.
Im struggling to figure out how to change the MAF units display field from lb/min to kg/hr
I wanted to show the modified sea level spark table for boost. The finished table is a bit different because the program only has 7 lines for entry and they make you leave the bottom line at 0 so you really only have 6 positions to make entries. The air loads I need to enter has 8 data points. So I had to skip the second and fourth on the entry table and the program averaged the two missing data points. Here is the result. Does this look ok to start with?
Sea Level Spark (only active spark table)
Sea Level Spark (only active spark table)
Bottom Line Up Front:
As the cars sits now, the tune is good and nothing is in the RED.
The passenger side side bank is learning to remove more fuel than the driver side for whatever reason.
It is at 68% of its learned fuel-removal allowance at that light-load operating point. It is removing 8.2% fuel under light load from a maximum learned fuel removal of 12.1%.
It could be for a number of reasons including something from the balance injector discussion from earlier in this post. It can also be a host of other things down to and including O2 sensor mismatch. Below is a list of things to check. Others might have some ideas as well.
The other clue is that the difference between banks got smaller as load increased.
In the warm, closed-loop cruise log, the median gap between the banks’ learned corrections decreased as raw load increased:
The passenger bank was learning to remove more fuel than the driver bank.
These are differences in learned correction—not measured AFR differences. Above 50% load, both learned values tended toward 1.000, but that alone doesn’t establish equal fueling; those cells may have had little learning.
For now, leave the BIN unchanged and keep the car naturally aspirated. Work through these checks and note what you find.
Additional Info I thought was relevant:
This is a comparison of your switching narrow band sensors against the wideband.
This tells me that your narrow band sensors are in pretty good agreement.
Comparison of clearly rich/lean readings during cruise:
If we can identify and reduce the difference between the banks, we’ll have a better foundation for global fuel adjustments, instead of choosing a compromise between the two.
As the cars sits now, the tune is good and nothing is in the RED.
The passenger side side bank is learning to remove more fuel than the driver side for whatever reason.
It is at 68% of its learned fuel-removal allowance at that light-load operating point. It is removing 8.2% fuel under light load from a maximum learned fuel removal of 12.1%.
It could be for a number of reasons including something from the balance injector discussion from earlier in this post. It can also be a host of other things down to and including O2 sensor mismatch. Below is a list of things to check. Others might have some ideas as well.
The other clue is that the difference between banks got smaller as load increased.
In the warm, closed-loop cruise log, the median gap between the banks’ learned corrections decreased as raw load increased:
| Raw load | Difference between banks |
|---|---|
| 10–20% | 5.47 percentage points |
| 20–30% | 3.13 points |
| 30–40% | 1.56 points |
| 40–50% | 0.78 points |
These are differences in learned correction—not measured AFR differences. Above 50% load, both learned values tended toward 1.000, but that alone doesn’t establish equal fueling; those cells may have had little learning.
For now, leave the BIN unchanged and keep the car naturally aspirated. Work through these checks and note what you find.
- Save the current tune.
Keep a copy of the exact BIN used for these logs. Record any changes made since loading the supplied file. - Compare the wideband gauge with the log.
At warm idle and a steady operating point, confirm the gauge and logged AFR agree. Confirm both measured and commanded AFR use the same gasoline AFR scale. - Record the O₂ sensor history.
Note their age, brand, part numbers if available, and whether both were replaced together. - Inspect the O₂ wiring.
Check connectors, damaged or heat-exposed wiring, and relevant grounds. Note anything different between the two sides. - Check for exhaust leaks ahead of the O₂ sensors.
Inspect header-to-head joints, collectors, and sensor fittings. Look for loose fasteners, soot marks, or ticking. - Check for intake and vacuum leaks.
A smoke test would help check intake joints, vacuum hoses, caps, PCV plumbing, and injector seals. Record the location of any leak before repairing it. - Inspect plugs and ignition components.
Keep the plugs identified by cylinder and compare their condition. Check plug wires and connections for damage or evidence of misfire. - Confirm whether the bank difference repeats.
Compare both banks after warmup at matching RPM and load. Preserve the existing logs and learned corrections before clearing codes or resetting memory. - If the difference persists, isolate the cause.
Compatible O₂ sensors can be swapped side to side to see whether the correction follows a sensor. If injector condition remains suspect, consider professional cleaning and flow testing, including operation at short pulse widths. - Review the findings before changing fuel values.
We want to resolve the roughly 12.30 commanded versus 12.8–13.1 measured WOT AFR, and understand the larger passenger-bank learned correction. Check fuel pressure if the findings point toward a delivery problem.
Additional Info I thought was relevant:
This is a comparison of your switching narrow band sensors against the wideband.
| Log | Wideband AFR at passenger narrowband switching | At driver narrowband switching |
|---|---|---|
| Warmup—warm portion | 14.663 | 14.665 |
| Cruise | 14.630 | 14.628 |
| Hot restart—closed loop | 14.633 | 14.637 |
This tells me that your narrow band sensors are in pretty good agreement.
Comparison of clearly rich/lean readings during cruise:
- Passenger narrowband and wideband agreed about 93% of the time.
- Driver narrowband and wideband agreed about 77% of the time.
If we can identify and reduce the difference between the banks, we’ll have a better foundation for global fuel adjustments, instead of choosing a compromise between the two.
First off, I have an X pipe that crosses immediately after the bell housing. The wideband is just aft of the X but on the drivers side. Nonetheless, being after the X, I’ve always assumed its measuring mix of both banks. Maybe not a perfect mix but some kind of mix at least. What do you think?
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