Journeyman

"And this one is just right" ~ Goldilocks
Joined
Aug 13, 2017
Messages
2,103
Location
Old Fort, NC 28762 USA
Ride
2020 3R
Looking for a good explanation of what those charts and figures mean when we look at a map on TuneEcu. I think for many of us its a complete mystery.

I just loaded a new tune and would like to better understand how it compares to my previous tune.

I don't plan on tinkering with a tune, just want to better understand it. For example......
  • What do the various tables represent and which ones are most important for us to understand?
  • What do the numbers represent in the individual cells?
  • What's up with the pretty colors?
  • What else should I ask, but too ignorant to think of? OK, let's just stick to this subject, for now ;-)
Many thanks, in advance.....

IMG_3442.JPG

 
This is fresh in my mind, as i was working last night on taking my favorite parts from two different tunes to create a starting point for my '18. Im sure someone will correct whatever i screw up

Maps f1-f3 represent the volume of air in each cylinder, 1-3. In milligrams i think? As your intake & exhaust become more efficient, this number needs to go up as the engine is moving more air. This is the number the computer uses to determine how much fuel to add.

The L1-L3 maps are similar, but instead of throttle %vs rpm, they use manifold pressure vs rpm. Manifold pressure is much more accurate at low throttle openings. These maps are only used below the throttle openings specified in the f-L switch table. Mainly during deceleration or low speed cruise.

I1-I3 control the ignition advance. I think table 1 is first gear ,2 is 2nd & 3rd, and 3 is 4th&5th, but I'm not sure. The genera consensus around here has been to use the same map for all three. I(N) controls the advance in neutral.

Finally we have the air/fuel map. This map sets the target for the computer to shoot for. It will use barometric pressure and air temp to adjust the values in the F tables for current conditions, and divide by the ratio in this table to determine how much fuel to inject. If the specified ratio is 14.5:1, and the O2 sensor is turned on, the computer will learn "trims" to adjust the fueling to hit this target. This allows it to adjust for air leaks , engine wear, or fuel quality. According to the tune ecu documentation, the richer areas of the map are never trimmed as the narrow band sensor can only determine leaner or richer than 14.5.

The other things in there are pretty self explanatory.

I have run one of @HansO 's maps in my 07 for five years and been very happy. Im pretty sure it's overly rich, but that's better than too lean. For my 18, I've got a data logger and a wideband O2 sensor, so I'm going to use that data to fine tune the maps. Although I've been working on vehicles for 20 years, this is my first time tuning a fuel injection system, so I'm trying to learn as much as i can. Typing this out is actually a good exercise to organize the info rattling around in my head.
 
This should be a good thread. I hope to learn. Lucky for us, a resident Captain now runs the Tune ECU. But @Claviger is building a land speed record breaking(we hope) Rocket for the Salt Flats. He is also building a "chopper". So he might be busy for a bit. Stay tuned to "Scar"

Yes, I've been enjoying his updates on that project. I decided to put this out "in the wild" knowing that he's got his hands full right now.
 
The F tables are fuel tables, the numbers you see are milligrams of air (x20). The tables are indexed by throttle position in % and rpm.
The values in the cells are what the ECU takes as quantities of air in milligrams at that rpm and throttle position. E.g. 4000mg of air at 10% throttle and 3000rpm.
F1 is the table for cylinder 1, F2 is for cylinder 2, and F3 is for cylinder 3.

F trim is a quick way to 'trim' values off those in the corresponding F (and L tables, if you select it under EDIT and apply trims), without changing the values in the F & L tables. That is, until you choose to 'commit' the trims, and then they will be added or subtracted from the F & L tables, depending on whether you put in a - or + trim. Think iirc the trims are in % rather than value with a unit like mg.

The L tables are also fuel tables, but for low throttle % positions, e.g. 0 - 6% throttle. The table is indexed by MAP readings (i.e. level of air pressure in the intake after throttle butterfly), and rpm.
The values in the cells are what the ECU takes as quantities of air (in milligrams x20) at that rpm and MAP value (air pressure) in hPa. E.g. 4500mg of air at 806 hPa MAP and 3000rpm.
L1, L2, L3 work the same as F1, F2, F3 for cylinders.

The I tables are the ignition tables, indexed by throttle position % and rpm. The numbers are degrees before top dead centre (BTDC). As in how many degrees before the piston reaches TDC that the ignition is fired.
E.g. 24.2° BTDC at 10% throttle and 3000rpm.
I1 is the table for 1st gear, I2 is for 2nd, and I3 is for gears 3 - 5.
I(N) is for when the engine is in Neutral.

I Trim works the same as F trim, except it's for the I tables.

Air/Fuel is the table of target air fuel ratio values that the ECU aims to achieve (indexed by % throttle and rpm).
It does so by injecting the amount of fuel necessary to achieve say 14.50 AFR at 3000rpm and 10% throttle, based on the value of air quantity in the corresponding cell in the F table (say 4000mg of air in this example).

Idle table is the target idle speed (RPM) the engine is ran at, a dynamic set point based on engine coolant temperature in °C (being the only accessible variable in this table).
E.g. at 17°C coolant temperature the target idle speed is 1018rpm, but by 57°C it has changed to 850rpm target idle speed.

Second throttle table values are the % open that the secondary throttle butterfly valves move to based on the table indexes of gear 1 - 5 and rpm engine speed. E.g. at 3250rpm in 3rd gear the secondaries are 27% open.

F-L Switch is apparently the place where the ECU switches over from getting it's air quantity values from the F tables and moves into the L tables (rpm coming down) and vice versa (rpm going up).
 
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The F tables are fuel tables, the numbers you see are milligrams of air. The tables are indexed by throttle position in % and rpm.
The values in the cells are what the ECU takes as quantities of air in milligrams at that rpm and throttle position. E.g. 4000mg of air at 10% throttle and 3000rpm.
F1 is the table for cylinder 1, F2 is for cylinder 2, and F3 is for cylinder 3.

F trim is a quick way to 'trim' values off those in the corresponding F (and L tables, if you select it under EDIT and apply trims), without changing the values in the F & L tables. That is, until you choose to 'commit' the trims, and then they will be added or subtracted from the F & L tables, depending on whether you put in a - or + trim. Think iirc the trims are in % rather than value with a unit like mg.

The L tables are also fuel tables, but for low throttle % positions, e.g. 0 - 6% throttle. The table is indexed by MAP readings (i.e. level of air pressure in the intake after throttle butterfly), and rpm.
The values in the cells are what the ECU takes as quantities of air in milligrams at that rpm and MAP value (air pressure) in hPa. E.g. 4500mg of air at 806 hPa MAP and 3000rpm.
L1, L2, L3 work the same as F1, F2, F3 for cylinders.

The I tables are the ignition tables, indexed by throttle position % and rpm. The numbers are degrees before top dead centre (BTDC). As in how many degrees before the piston reaches TDC that the ignition is fired.
E.g. 24.2° BTDC at 10% throttle and 3000rpm.
I1 is the table for 1st gear, I2 is for 2nd, and I3 is for gears 3 - 5.
I(N) is for when the engine is in Neutral.

I Trim works the same as F trim, except it's for the I tables.

Air/Fuel is the table of target air fuel ratio values that the ECU aims to achieve (indexed by % throttle and rpm).
It does so by injecting the amount of fuel necessary to achieve say 14.50 AFR at 3000rpm and 10% throttle, based on the value of air quantity in the corresponding cell in the F table (say 4000mg of air in this example).

Idle table is the target idle speed (RPM) the engine is ran at, a dynamic set point based on engine coolant temperature in °C (being the only accessible variable in this table).
E.g. at 17°C coolant temperature the target idle speed is 1018rpm, but by 57°C it has changed to 850rpm target idle speed.

Second throttle table values are the % open that the secondary throttle butterfly valves move to based on the table indexes of gear 1 - 5 and rpm engine speed. E.g. at 3250rpm in 3rd gear the secondaries are 27% open.

F-L Switch is apparently the place where the ECU switches over from getting it's air quantity values from the F tables and moves into the L tables (rpm coming down) and vice versa (rpm going up).


Wow!! Now my head hurts!!
 
The F tables are fuel tables, the numbers you see are milligrams of air. The tables are indexed by throttle position in % and rpm.
The values in the cells are what the ECU takes as quantities of air in milligrams at that rpm and throttle position. E.g. 4000mg of air at 10% throttle and 3000rpm.
F1 is the table for cylinder 1, F2 is for cylinder 2, and F3 is for cylinder 3.

F trim is a quick way to 'trim' values off those in the corresponding F (and L tables, if you select it under EDIT and apply trims), without changing the values in the F & L tables. That is, until you choose to 'commit' the trims, and then they will be added or subtracted from the F & L tables, depending on whether you put in a - or + trim. Think iirc the trims are in % rather than value with a unit like mg.eh

The L tables are also fuel tables, but for low throttle % positions, e.g. 0 - 6% throttle. The table is indexed by MAP readings (i.e. level of air pressure in the intake after throttle butterfly), and rpm.
The values in the cells are what the ECU takes as quantities of air in milligrams at that rpm and MAP value (air pressure) in hPa. E.g. 4500mg of air at 806 hPa MAP and 3000rpm.
L1, L2, L3 work the same as F1, F2, F3 for cylinders.

The I tables are the ignition tables, indexed by throttle position % and rpm. The numbers are degrees before top dead centre (BTDC). As in how many degrees before the piston reaches TDC that the ignition is fired.
E.g. 24.2° BTDC at 10% throttle and 3000rpm.
I1 is the table for 1st gear, I2 is for 2nd, and I3 is for gears 3 - 5.
I(N) is for when the engine is in Neutral.

I Trim works the same as F trim, except it's for the I tables.eh

Air/Fuel is the table of target air fuel ratio values that the ECU aims to achieve (indexed by % throttle and rpm).
It does so by injecting the amount of fuel necessary to achieve say 14.50 AFR at 3000rpm and 10% throttle, based on the value of air quantity in the corresponding cell in the F table (say 4000mg of air in this example).

Idle table is the target idle speed (RPM) the engine is ran at, a dynamic set point based on engine coolant temperature in °C (being the only accessible variable in this table).
E.g. at 17°C coolant temperature the target idle speed is 1018rpm, but by 57°C it has changed to 850rpm target idle speed.

Second throttle table values are the % open that the secondary throttle butterfly valves move to based on the table indexes of gear 1 - 5 and rpm engine speed. E.g. at 3250rpm in 3rd gear the secondaries are 27% open.

F-L Switch is apparently the place where the ECU switches over from getting it's air quantity values from the F tables and moves into the L tables (rpm coming down) and vice versa (rpm going up).
Nice intro :sneaky: - Now please the full on mega geeky version :coffee:. Yes!, I am sitting comfortably. :p
 
This should be a good thread. I hope to learn. Lucky for us, a resident Captain now runs the Tune ECU. But @Claviger is building a land speed record breaking(we hope) Rocket for the Salt Flats. He is also building a "chopper". So he might be busy for a bit. Stay tuned to "Scar"

Only one small problem Kenny @TheKid . A certain blowhard who shall remain nameless got back in here and decided to get in Robs grill. Rob said he was through with the site as long as said blowhard was hanging around, checked out last month and ain't been back on.

Not much of a trade I reckon.
 
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