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I already messed with transits to where it richens up on tip in. The lean condition persists for some time where I suspect it is a delay between the fuel pump DC modulation and the injector pulse width compensation - but you could have a point there.

I see the lean condition mostly when pump DC is not 100%. But, it's worth taking another look at. Part throttle can be so tricky!

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was just thinking because its at a throttle shift and seems fine once it gets to full throttle, hows the PE enrichment rate ? desoot mode is disabled ? yea damn part throttle... im also using mechanical reg manifold referenced so just letting it do all the hard work, also see if its better or worse with quicker or slower throttle movement as it might just take a bit to keep up with the fuel demand as u were thinking, the pressure should be instant but the mechanical change in pressure may be slower to respond
 

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Well, my noob part throttle tuning has giving me much better driveability and gained a solid 1 MPG in the city alone... BONUS!! I haven't driven all highway yet but I suspect better MPGs as well.

Thanks Jesse!

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Just an FYI, "GoatRope Garage" on youtube has some great Gen IV tuning stuff. I referenced him a lot in my tuning. I figure that after commenting in some other threads, I would post my general tuning approach here for TFNGs to consider:

------------------------- STEP 1: ----------------------------
MAF-Only Tuning: save as temporary file.
** Try to avoid sharp throttle changes for MAF only tuning, so readings are more accurate.

Temporarily disable VVE/SD via the following:
* Airflow / Dynamic: Dynamic Airflow - disable (set disable to 100 RPM, re-enable to 90 RPM).
Temporarily disable Closed Loop:
  • Fuel / Oxygen Sensors - O2 readiness ECT: disable closed loop (set to 400* F).
  • Fuel / Oxygen Sensors - LTFT (Min ECT 400* F, Max ECT 10* F).
  • Fuel / Temperature Control - Catalyst Protection (COT disabled).
Temporarily disable DFCO:
  • Fuel / Cutoff, DFCO - Clutch Fuel Cutoff (disable to 300 MPH, 8000 RPM).
  • Fuel / Cutoff, DFCO - Deceleration Fuel Cutoff (enable 400* F, disable 399* F)
  • Fuel / Lean/Fuel-Saving - DoD disable.

Setup histogram for MAF in Hz and EQ ratio.
1st Parameter, EQ error (Math)
2nd Parameter, MAF for column axis in Frequency
Make sure to copy column axis values from ECM Tuner MAF output frequency

** You may need to create two histograms for Low and High frequency MAF tables **

Once histogram populated, copy/paste "special" as percent change to ECM Tuner tables. Repeat data logs if desired, then copy / paste MAF frequency tables to original tune file.

------------------------- STEP 2: ----------------------------
VVE(speed density) Tuning: save as temporary file.
The goal is non-PE "stoich" tuning. Consider raising PE minimums, and driving in variable conditions in EACH gear to hit more load cells.

Temporarily disable MAF via the following:
* Engine Diagnostics / Airflow - MAF freq Fail (Fail High 2 Hz, Fail Low 1 hz)
* Set P0103 to fail on 1st error.
Temporarily disable Closed Loop:
  • Fuel / Oxygen Sensors - O2 readiness ECT (set to 400* F).
  • Fuel / Oxygen Sensors - LTFT (Min ECT 400* F, Max ECT 10* F).
  • Fuel / Temperature Control - Catalyst Protection (COT disabled).
Temporarily disable DFCO:
  • Fuel / Cutoff, DFCO - Clutch Fuel Cutoff (disable to 300 MPH, 8000 RPM).
  • Fuel / Cutoff, DFCO - Deceleration Fuel Cutoff (enable 400* F, disable 399* F)
  • Fuel / Lean/Fuel-Saving - DoD disable.

Setup histogram for EQ ratio and MAP.
1st Parameter, EQ Ratio
2nd Parameter, Engine RPM for column axis,
3rd Parameter, Manifold Absolute Pressure for row axis.
Make sure to copy column/row axis values from ECM Tuner VVE tables to match.

Once histogram populated, copy/paste "special" as percent change to ECM Tuner VVE tables - all four should match. Smooth out boundaries if needed. Repeat data logs if desired, then reset Closed Loop, DFCO and MAF enable settings equal to original tune file.

Use 2013 Camaro LZ1 Zone boundaries for VVE: VVE zone question, found nothing definitive on a search.
I agree, Kyle at GoatRope is very knowledgeable, personable 'and' entertaining. I've learned a lot watching his youtube videos over, and over, and over, until the bulbs start to brighten. I am also a contributing monthly supporter of his channel in gratitude for the excellent service her performs.
 

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For idle tuning (assuming a new, larger cam), I'd start at commanding around 15* advance for the cell values at ide range (generally, 6-1000 RPM with "airmass" between .20- .52 (g) in the idle timing table), and start with a reasonable target idle RPM - you can work down later as you dial things in. If you command to little timing, it will skew your airflow requirements in the same way if you command too much timing, it will be harder to dial in. Timing, airflow, fuel and commanded RPM all interplay with one another, so sometimes you just have to start somewhere: and I'd suggest getting your MAF sensor adjusted, commanding 15* idle advance and working from there on airflow requirements. I'd also suggest turning VVE off to help minimize the variables. Your MAF sensor has to be calibrated well for this to work (see above), otherwise you'll have big swings in cold start and closed-loop fuel trims. Bear in mind that for larger cams, your O2 sensor may NOT be accurate due to slow exhaust velocity, cam overlap, and temperature.

You will almost always have to lower your Airflow Final Minimum table a significant amount (20-40%?), as well as the ECT Multi table below it for temps below 60*. Once you feel idle is decent, I'd suggest matching the same idle cell values in your Idle Spark Advance table to the High Octane spark table to avoid big jumps in commanded timing - you can sometimes feel that in the car.

When you data log, you must data log "Idle Adaptive Advance." Every time you touch the gas, this flat-lines, but as soon as the computer realizes your idling (clutch in / neutral for us M6 guys, usually 0mph for Auto Guys); the Idle Adaptive advance starts adjusting: negative values mean it's trying to REDUCE airflow to match your target idle RPM. positive values means it's adding airflow to keep your target RPM. You will almost always be negative: reduce Airflow Final Minimums further. Remember to pay attention to your engine coolant - cold starts are different than fully warmed up and driving around town (ECT multi table vs Airflow Final Minimum table). When you notice massive "negative timing" adjustments in your data log, like JAustin does, this is a second way the computer tries to reduce your idle RPM: pulling timing. Do not add more timing back into the idle timing table; meaning don't command 30 degrees and hope that you get 15* actual - continue to lower your minimum idle airflow parameters and this will take care of itself.

If you get "flare" on cold start, where your motor winds up to 1500 RPM and then settles back down to a more normal RPM range, you will want to lower your MAF S/S Startup table: this assumes a specific MAF frequency based on temperature on cold starts before the airflow in your intake has stabilized; IIRC it's just a few seconds before it transitions to using actual MAF data. If you need to change it, do it 5% at a time. Remember this is indexed to ECT temperatures.

Once you get close and you feel your idle Adaptive advance is within a few degrees of zero oscillating pretty uniformly, your timing should be pretty stable within 5* or so as well when data logging at idle. It's better to run slightly more timing than not enough, both in the heat generated in the exhaust, mean brake torque output and idle stability - but every combo can be different due to cams, head flow, compression, fuel, etc. For Manual guys, if you run too little timing the motor will tend to stall easier. Once you get your airflow tables adjusted, you will likely be able to add another degree or two of timing back in - you can test this using the HP Tuners VCM special functions option while actively data logging.

Another way to think of this is: with the car fully warmed up, on 93 pump gas, once you command a reasonable idle timing advance and RPM (say, 15* advance and 850 RPM); drop your airflow tables by a decent margin (20%) and see what happens. If your idle adaptive advance is negative, lower those tables more. If the car stalls out, and/or your idle adaptive advance is POSITIVE, then revert back to your previous tune and lower the Airflow Final Minimum table half as much. :) If your idle surges, and these parameters are otherwise pretty close to dialed in, you'll likely want to INCREASE your "Enable RPM error" tables slightly - you want to relax the computer's attempt at controlling idle RPM with bigger cams, so wider tolerance with the RPM error tables.

Bear in mind for FLEX fuel idle and part-throttle timing, you will want to pull total timing using the flex fuel modifier table. A rule of thumb is to pull timing at idle and part-throttle ranges by 4-5* advance, as ethanol has a faster flame front than pump gas and thus reaches maximum torque faster (ie with less timing advance). You only use additional timing advance with ethanol when your engine is "octane limited," which for us is usually near or at peak engine load, or when you push the skinny pedal most of the way down. I strongly recommend you get your pump-gas tables perfect before messing with ethanol, as "riding the knock sensor" under ethanol is much more destructive due to higher chamber pressures and bad things happen.

These are my random thoughts on idle tuning, I recommend you ignore them and pay a professional. I'm only posting here so I can save my notes for posterity, etc. :p
FYI:
Jeff emailed to inform me that he has added six more training videos to the Gen4 HPtuner series of training videos. (see image)

I run 92, MAF only, but I know there are a lot of owners that run flex, might be something to consider.
Automotive parking light Wheel Car Tire Land vehicle
 

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FYI:
Jeff emailed to inform me that he has added six more training videos to the Gen4 HPtuner series of training videos. (see image)

I run 92, MAF only, but I know there are a lot of owners that run flex, might be something to consider. View attachment 159433
Is this a subscription service?
 

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For idle tuning (assuming a new, larger cam), I'd start at commanding around 15* advance for the cell values at ide range (generally, 6-1000 RPM with "airmass" between .20- .52 (g) in the idle timing table), and start with a reasonable target idle RPM - you can work down later as you dial things in. If you command to little timing, it will skew your airflow requirements in the same way if you command too much timing, it will be harder to dial in. Timing, airflow, fuel and commanded RPM all interplay with one another, so sometimes you just have to start somewhere: and I'd suggest getting your MAF sensor adjusted, commanding 15* idle advance and working from there on airflow requirements. I'd also suggest turning VVE off to help minimize the variables. Your MAF sensor has to be calibrated well for this to work (see above), otherwise you'll have big swings in cold start and closed-loop fuel trims. Bear in mind that for larger cams, your O2 sensor may NOT be accurate due to slow exhaust velocity, cam overlap, and temperature.

You will almost always have to lower your Airflow Final Minimum table a significant amount (20-40%?), as well as the ECT Multi table below it for temps below 60*. Once you feel idle is decent, I'd suggest matching the same idle cell values in your Idle Spark Advance table to the High Octane spark table to avoid big jumps in commanded timing - you can sometimes feel that in the car.

When you data log, you must data log "Idle Adaptive Advance." Every time you touch the gas, this flat-lines, but as soon as the computer realizes your idling (clutch in / neutral for us M6 guys, usually 0mph for Auto Guys); the Idle Adaptive advance starts adjusting: negative values mean it's trying to REDUCE airflow to match your target idle RPM. positive values means it's adding airflow to keep your target RPM. You will almost always be negative: reduce Airflow Final Minimums further. Remember to pay attention to your engine coolant - cold starts are different than fully warmed up and driving around town (ECT multi table vs Airflow Final Minimum table). When you notice massive "negative timing" adjustments in your data log, like JAustin does, this is a second way the computer tries to reduce your idle RPM: pulling timing. Do not add more timing back into the idle timing table; meaning don't command 30 degrees and hope that you get 15* actual - continue to lower your minimum idle airflow parameters and this will take care of itself.

If you get "flare" on cold start, where your motor winds up to 1500 RPM and then settles back down to a more normal RPM range, you will want to lower your MAF S/S Startup table: this assumes a specific MAF frequency based on temperature on cold starts before the airflow in your intake has stabilized; IIRC it's just a few seconds before it transitions to using actual MAF data. If you need to change it, do it 5% at a time. Remember this is indexed to ECT temperatures.

Once you get close and you feel your idle Adaptive advance is within a few degrees of zero oscillating pretty uniformly, your timing should be pretty stable within 5* or so as well when data logging at idle. It's better to run slightly more timing than not enough, both in the heat generated in the exhaust, mean brake torque output and idle stability - but every combo can be different due to cams, head flow, compression, fuel, etc. For Manual guys, if you run too little timing the motor will tend to stall easier. Once you get your airflow tables adjusted, you will likely be able to add another degree or two of timing back in - you can test this using the HP Tuners VCM special functions option while actively data logging.

Another way to think of this is: with the car fully warmed up, on 93 pump gas, once you command a reasonable idle timing advance and RPM (say, 15* advance and 850 RPM); drop your airflow tables by a decent margin (20%) and see what happens. If your idle adaptive advance is negative, lower those tables more. If the car stalls out, and/or your idle adaptive advance is POSITIVE, then revert back to your previous tune and lower the Airflow Final Minimum table half as much. :) If your idle surges, and these parameters are otherwise pretty close to dialed in, you'll likely want to INCREASE your "Enable RPM error" tables slightly - you want to relax the computer's attempt at controlling idle RPM with bigger cams, so wider tolerance with the RPM error tables.

Bear in mind for FLEX fuel idle and part-throttle timing, you will want to pull total timing using the flex fuel modifier table. A rule of thumb is to pull timing at idle and part-throttle ranges by 4-5* advance, as ethanol has a faster flame front than pump gas and thus reaches maximum torque faster (ie with less timing advance). You only use additional timing advance with ethanol when your engine is "octane limited," which for us is usually near or at peak engine load, or when you push the skinny pedal most of the way down. I strongly recommend you get your pump-gas tables perfect before messing with ethanol, as "riding the knock sensor" under ethanol is much more destructive due to higher chamber pressures and bad things happen.

These are my random thoughts on idle tuning, I recommend you ignore them and pay a professional. I'm only posting here so I can save my notes for posterity, etc. :p
Have you ever experienced or would know the cure if the car is wanting to stall right after start up? thanks!
 

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Discussion Starter · #68 ·
Have you ever experienced or would know the cure if the car is wanting to stall right after start up? thanks!
If it stalls when hot and cold, you need to multiply your minimum airflow tables (under Idle tab, then Airflow) by a decent percentage, probably ~1.2x or so (20%).

If it runs well when warm, but stalls out on cold start, raise your Airflow vs ECT tables in the colder temps by a LOT, and then extrapolate over the temperature range. Increase the -40*F something like 40-50% and then extrapolate across the range to 220*F.

Checking VVE is always a good idear.
 

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If it stalls when hot and cold, you need to multiply your minimum airflow tables (under Idle tab, then Airflow) by a decent percentage, probably ~1.2x or so (20%).

If it runs well when warm, but stalls out on cold start, raise your Airflow vs ECT tables in the colder temps by a LOT, and then extrapolate over the temperature range. Increase the -40*F something like 40-50% and then extrapolate across the range to 220*F.

Checking VVE is always a good idear.
It happens more on cold starts, hot starts are ok but it does surge for like 2 seconds then idles perfect! I'm going to try your suggestions, thanks!

are u running maf or just vve ?
I'm running MAF only
 

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If it stalls when hot and cold, you need to multiply your minimum airflow tables (under Idle tab, then Airflow) by a decent percentage, probably ~1.2x or so (20%).

If it runs well when warm, but stalls out on cold start, raise your Airflow vs ECT tables in the colder temps by a LOT, and then extrapolate over the temperature range. Increase the -40*F something like 40-50% and then extrapolate across the range to 220*F.

Checking VVE is always a good idear.
"If it runs well when warm, but stalls out on cold start, raise your Airflow vs ECT tables in the colder temps by a LOT"
Just to make sure I understand. My M6 struggles a bit on cold starts as well, MAF only. The 'Airflow vs ECT' would you mind posting a screenshot of the table location, just want to make sure. Also, "a LOT" like 20%?
 

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"If it runs well when warm, but stalls out on cold start, raise your Airflow vs ECT tables in the colder temps by a LOT"
Just to make sure I understand. My M6 struggles a bit on cold starts as well, MAF only. The 'Airflow vs ECT' would you mind posting a screenshot of the table location, just want to make sure. Also, "a LOT" like 20%?
I believe he’s taking about the tab right under “base running airflow”
Engine - idle - airflow
 

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if ur using MAF then the first few seconds after starting the maf isnt used so the maf s/s startup table should be adjusted for estimated startup airflow, also there isnt really a maf only as the vve will be used for throttle transients so best to have that dialed in as well
 

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if ur using MAF then the first few seconds after starting the maf isnt used so the maf s/s startup table should be adjusted for estimated startup airflow, also there isnt really a maf only as the vve will be used for throttle transients so best to have that dialed in as well
Haven't spent any time on tuning the VVE, guess that's where I'll focus my future efforts. Overall seems the MAF tune has been doing a good job? I 'supposedly' disabled the VVE, but from what you have previously past written, the VVE is never really completely disabled. So it's possible the VVE does some things regardless that I am not familiar and completely unaware.
 

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if u give ur throttle a stomp then vve is used no matter how its set, vve cant be turned off without zeroing it out which i dont recommend, thats why factory dont favor maf until after 4000rpm it likes more steady flow not the start/stop traffic stuff varying throttle always changing that more vve related for accuracy
 

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Discussion Starter · #78 ·
"If it runs well when warm, but stalls out on cold start, raise your Airflow vs ECT tables in the colder temps by a LOT"
Just to make sure I understand. My M6 struggles a bit on cold starts as well, MAF only. The 'Airflow vs ECT' would you mind posting a screenshot of the table location, just want to make sure. Also, "a LOT" like 20%?
Here's what I'm talking about - the ECT table under base running airflow. But full disclaimer, your basics like MAF calibration, timing, fuel, etc all need to be pretty well dialed in, otherwise you'll be chasing your tail.

Tuners can do some wild shit and still have the car run pretty well when warm. Lol.



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if ur using MAF then the first few seconds after starting the maf isnt used so the maf s/s startup table should be adjusted for estimated startup airflow, also there isnt really a maf only as the vve will be used for throttle transients so best to have that dialed in as well
Awesome thank you I'm going to mess with MAF s/s one of these days, The issue is with my buddy's car I had it dialed in on startup til he put a 2650 now it surges
 

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Yeah, I couldn't tell if you were being sarcastic (or not) above - but I could have sworn the conventional wisdom was to raise the High Flow thresholds, so I wanted to correct that notion here. You were spot on with the duty Cycle vs voltage changes.

Although now, because I am getting 100% duty cycle sooner, I would not have need to change the voltage vs flow duty cycle tables - though the DW pumps certainly like it. On factory pumps, I suspect it might be more limited in use.

Right now, I have left it at ~300lb-hr flow rate just because that corresponds well to the lowest RPM range for each shift. I think I will lower it even further, so I get High Flow at ~3k RPM no matter what - I'll just have to keep an eye on rail pressure. I suspect that lean area early in the run is a side-effect of the pump DC being modulated.... or it could just be my tune.
"I'll just have to keep an eye on rail pressure. I suspect that lean area early in the run is a side-effect of the pump DC being modulated.... or it could just be my tune."

I note what appears to be a "lean delay" reaching my commanded fuel when performing a rolling 4th gear hard pull at say 60ish mph? Doesn't appear to delay in hard pull 3rd gear? RPMs are similar, fuel pressures, fuel flow?

Another interesting observation, I consistently go into high flow mode, fuel pressure jump at 5000rpm regardless of fuel flow rate into the mid 60psi range? It's as if there's a defined value somewhere to trigger this? Any insight? ty
 
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