***Note -- this is a work in progress -- I will add to and edit this thread as needed. If anything isn't clear, just let me know -- it is admittedly a bit rough, but should be very helpful for those tuning with the EMU****
Street Tuning the E-manage Ultimate (EMU) to Minimize Long Term Fuel Trims (LTFT’s)
Please note that this thread is NOT intended to be a guide for tuning the EMU to achieve maximum safe power. That goal is best achieved on a dyno with the help of a skilled tuner.
However, the steps described in this thread will greatly facilitate your ability to extract optimal safe power out of your car with the EMU.
The Problem with Piggyback Controllers
The major problem with piggyback controllers is that they are always fighting the ECU in closed loop (partial throttle) for control of the fuel injectors (for a detailed explanation of why this is the case please read this thread http://www.newcelica.org/forums/showthread.php?t=84901).
If a given load cell in a piggyback map commands the injectors (either by spoofing air flow signals or direct control) to inject a quantity of fuel that will lead to a (narrowband measured) AFR that is greater or lower than the ECU is programmed to allow, the ECU will retaliate by trimming (adding or subtracting) fuel from those load cells.
The high fuel trims have two undesirable effects (1) they can royally screw up drivability, and (2) they can interfere with any changes made to your WOT tune.
This is because the ECU will determine (by means that are not entirely clear) an appropriate LTFT to apply to the cells that are activated in open loop (WOT).
If this number is relatively high (for sake of argument, let’s say greater than 9%) it may adversely affect the power (run too rich) or safety (run too lean) of your tune. Therefore, it would be desirable to minimize or eliminate all of the LTFT’s BEFORE tuning for optimal power.
More on LTFT’s
Contrary to what some of you may think, there isn’t a single LTFT in closed loop, but MANY. The Toyota ECU creates LTFT’s for small blocks of load cells in its map – I’ve found some evidence that there may be individual LTFT’s for individual cells! (Probably, they are eventually averaged so that you have less variation in the LTFT’s across blocks of cells, but this is all top secret ECU voodoo that few people know about in great detail).
Although you cannot see the Toyota ECU’s map like you can on the EMU (and there are several, not merely a single map), you CAN record all of the LTFT’s in real time while driving, and identify which cell on your EMU map is associated with each recorded LTFT. Then you can make changes to the corresponding EMU cell to minimize or eliminate the trim.
I’ll show you how to accomplish this task step-by-step.
Ideally, when you are done, all LTFT’s will be close to zero (for our purposes, let’s say < 10%, but hopefully closer to %5 or less)*, and the LTFT carried into WOT will be almost zero.
Before you begin, you will need the following items:
1. Laptop and most current version of EMU software.
2. An OBDII scan tool capable of logging ECU data from the OBDII port. I use the Auterra tool with my Palm pilot – for more details go here http://www.auterraweb.com/dynokitsnohotsync.html
3. Ideally, a wideband AFR gauge (although this is not abosolutely necessary to tune out fuel trims, you'll need it for power tuning and for monitoring the car).
4. Considerable patience
5. Go to a professional tuner if you don't know what you're doing. Err on the side of caution. Basically, if what I say makes no sense to you, just pass on these suggestions to your tuner...
Once you have the prerequisite items, here’s what to do before you begin:
1. Go to the parameter menu. Make sure the stock injector value is correct. If you had/have the yellow injectors that value should be 310 and if brown it should be 330. If you have new injectors of a different size, enter in the value for the new injectors you are using.
As to the inj lag time, if you have a value in there that is working for you, just leave it alone for now. If not, this will take some trial and error to set correctly, but I can tell you that the car won't idle properly if the value is too high (idles overly rich) or too low (idles overly lean). High fuel trims at idle are a sign that the inj lag isn't set quite right... As far as I can tell, when warm, it should idle around 14.7 - 15.1 AFR (or a tad leaner) and between 13.0 - 14.0 AFR when cold. More on this later...
2. Zero out the airflow map, at least through 2K in low load. Worthless. All it's doing is throwing things off. I would only mess with this if you are having idle problems due to your intake. Best to leave this zeroed though, IMO [**BUT, SEE NOTE BELOW].
If you are working with an airflow map that has adjustments to the high load cells, I recommend you leave them as they are for now, as they are probably keeping the MAF from maxing out.
I will have additional tuning suggestions added later for what to do if the MAF is maxing out and how to tell when this is happening (hint, if you are logging inj input duty cycles close to 100%, the ECU is not happy with you and you need to adjust airflow voltage readings in the affected cells and or use the boost limiter to clamp the airflow readings!).
3. Datalog your MAF voltage readings and re-scale your Y axis on all the relevant maps based on your voltage. Evenly spaced break points going up by .2 volts is a good starting point, but this will take some experimentation. The range is going to be 1 - 5v.
Likewise, scaling the x axis (RPM's) will take a little trial and error to find the right breakpoints, but evenly spaced intervals, though a good starting point, is probably not going remain consistent throughout the map.
Just be sure to scale all your load-based maps the same way.
Recording and tuning out Long Term Fuel Trims (LTFT)
1. Zero out all the low load (closed loop) cells in the inj map, if you haven't already done so. Again, make sure the airflow adjustment map low load cells are also zeroed out as well [**SEE NOTE BELOW]
2. Reset the ECU.
3. Start the car; get it up to operating temp.
Hook up your laptop and data log RPM and airflow voltage on the EMU. You may have the map trace on if you wish to help focus on specific load cells while driving.
Hook up the OBD II datalogger and record RPM and LTFT bank 1 -- these are the only two ECU variables you care about right now.
4. Drive around for at least 30 minutes (drving around longer is better -- see "HINT" below). Try to hit as many load points -- all in part throttle, closed loop, just crusing around -- as possible on the emanage fuel map. While doing this, record LTFT and RPM on your scantool.
At the same time, have the lap top recording RPM and, if you wish airflow voltage, (really, all you need is RPM). You may have the map trace on if you wish, but it's not necessary.
Note that the LTFT’s that are recorded on the OBD II reader change as you hit different load cells on the EMU map – this is because there are separate LTFT's associated with either individual cells or at least a cluster of cells in the ECU's fuel map.
BTW, also note that the ECU cuts fuel when decelerating (if you have a wideband, you will see the gauge indicate a severely lean condition in decel) -- therefore, don't worry too much about part throttle load cells activated when decelerating -- basically, you are temporarily in open loop and it doesn't seem to affect things much if at all. You can probably leave those particular cells (high RPM, lowest load), zeroed out.
HINT: If you have the time, it's better to drive for several hours (or even wait several days) so that LTFT's stabilize and THEN datalog. When datalogging, it's also worthwhile to record the Short Term Fuel Trims (STFT).
Eventually, the STFTs will minimize in value and should fluctuate back and forth between small positve and negative values.
Once the STFTs have minimized (don't be alarmed by an occasional large one), you know that the LTFTs should be stable, and time to make corrections.
The biggest factor that will affect this is the weather -- the best time to do this is when it's right around the average weather temperature for the time of year that you are tuning (i.e., don't pick the hottest day or coldest night of the year! Ideally, you'd do it on a day with low to moderate humidity and about 75* F.
Either way, you probably need to tweak things once or twice a year -- it's good to check the fuel trims at least once every couple of months).
5. Go home. Bring in the lap top and the OBD II datalogger to review the recorded data from both.
When you review the OBD II data, you should play it back as a graph displaying both recorded values (i.e., RPM and LTFT) at the same time.
It will look something like this:
In reviewing the OBD II data, take note of LTFT's and RPM on the scantool recording.
Pause the play back, and you can select individual data points.
Your goal is to match this OBD II data to the data recorded on EMU in order to locate cells that need tuning on your EMU inj adj map.
By eyeballing the shape of the recorded RPM curve from the OBD II data log, you will be able to easily locate the same RPM/load region on the emanage map that corresponds to the one datalogged with a given LTFT on your scantool.
Then it's simply a matter of selecting the datapoint on the EMU data log that matches the one you've selected on the OBD II datalog.
Observe (Click on thumbnail for larger images)…
Click on thumbnail for larger images.
If you click on an RPM data point in the recorded emanage graph that matches the same spot on your OBDII datalog, you will be able to figure out what LTFT was associated with the corresponding load cell in the EMU inj adj map.
Go look at your fuel map on the emanage. The data point that you clicked on in the EMU datalog will automatically highlight the corresponding cell in your inj adj map.
If the logged LTFT on the OBD scantool that matches the selected datapoint on the EMU datalog graph/inj adj map was negative, subtract some fuel from that cell. If positive, add some fuel to that cell.
If you find you get a wide variety of LTFT's in that same cell, you may need to add another break point in the fuel map for greater resolution.
6. Make small changes to your EMU map, flash it to the EMU, and drive around as you did before, once again recording with the laptop and OBD II datalogger as previosuly described.
Repeat these procedures until all LTFT's are in the single digits (as close to 0.0 as possible).
7. Now comes the scary part: Reset ECU and do it all over again -- you need to do this to help ensure that the LTFT's will always be low even if the ECU is reset -- remember, the ECU is always adjusting itself, so you want your tune to allow that to happen without high LTFT's being created unexpectedlly.
If your tune was good, after driving around for a little while, the LTFT's should stabilizie, and be very close to where they were previously (i.e., low single digits).
Be sure to give it a few hours of driving to ensure that all the LTFT’s have stabilized.
It will always vary a little bit due to ambient temp, but ideally, it will remain in low single digits or close to zero under all operating conditions -- that's the goal!
***NOTE: What's most important is that the LTFT that is carried into open loop is close to zero (mine is < 1%). If you have a few cells where the LTFT is a bit high, but drivability is fine and the WOT (open loop) LTFT is low, you're golden.
To determine your LTFT in WOT (open loop): Floor it and datalog the LTFT. Whatever that number is should remain fairly constant once LTFT's in the rest of the map have stablized.***
This whole process can take hours or even DAYS, and it is one of the main reasons why folks generally hate working with piggybacks.
That said, if you can endure it, eventually you can get the car running very smoothly off and on boost.
*Note on fuel trims. Keep in mind that the fuel trims correspond to a change in inj duty cycle that moves the AFR to a value the ECU will accept.
HOWEVER -- it should also be noted that if you are using larger than stock injectors, the actual effect it has on your output duty cycle will be less than the ECU claims.
In other words, if you are running injectors that are 50% larger than stock, the actual effect of the duty cycle change commanded by the ECU will be less (not exactly 50% less, though...).
The ECU has no idea you are using larger injectors; it's merely additng or subtracting fuel until it sees a narrowband measured AFR voltage it likes. The amount reported reflects the amount of correction ECU "thinks" it has made based on it's mistaken assumption of stock injectors.
Anyway, I'm pointing this out because in the afforementioned example, a recorded LTFT of 5% would probably really be only create a 2-3% correction.
Using the AFR target Map to maintain desired AFR's in WOT
Coming soon! Short version is, by creating a closed loop map on the cells activated in WOT, you will be able to more easily keep your AFR's where you want them even when there are dramatic changes in weather conditions and even if the (small) fuel trim that gets applied to WOT changes slightly.
Further Improving Drivability: Tuning Injector Acceleration Enrichment
Quick inputs to the throttle will result in an abrupt change in the AFR as a large mass of air is ingested. Unfortunately, this may create a momentary lean condition and hesitation off idle. This is corrected by injecting extra quantity of fuel for a few milliseconds. You may also tune this feature with the EMU.
If you are getting hesitation off idle, use the map trace on the injector acceleration enrichment map, and take note of which cells are activated when it hesitates. You'll most likely need to add or subtract fuel to those cells.
Drive around for a while, somewhere where you can stop and start, applying different degrees of throttle to take off -- a big, deserted parking lot would be a good place to do this. This is tedious and will take a while to dial in, but you can get the car to have excellent throttle response with trial and error.
How to Use the Emanage Rev limit Cut Setting
For details, please see this thread http://www.newcelica.org/forums/showthread.php?t=275482
NOTE ON AIRFLOW CORRECTION
If your intake tube has an inside diameter that is larger than the stock 2.5", you might try making a global correction to the airflow map (at least in map cells activated in part throttle). The global correction should be approximately equal to the difference in the diameter of the intake tube from the stock diameter.
Example: The stock tube has a 2.5" inside diameter (i.e., 63.5 mm). If you are using an intake with a 3" inside diameter (i.e., 76.2), that's a difference of 20%. Therefore, you would make a correction of 20% in all of the cells of the airflow map, or at least those that are activated in part throttle (in WOT, especially if under boost, you may or may not want to do this -- I'd determine that empirically).
If you need to make this correction, it should be done BEFORE tuning out any fuel trims or tuning for drivability or power.
Street Tuning the E-manage Ultimate (EMU) to Minimize Long Term Fuel Trims (LTFT’s)
Please note that this thread is NOT intended to be a guide for tuning the EMU to achieve maximum safe power. That goal is best achieved on a dyno with the help of a skilled tuner.
However, the steps described in this thread will greatly facilitate your ability to extract optimal safe power out of your car with the EMU.
The Problem with Piggyback Controllers
The major problem with piggyback controllers is that they are always fighting the ECU in closed loop (partial throttle) for control of the fuel injectors (for a detailed explanation of why this is the case please read this thread http://www.newcelica.org/forums/showthread.php?t=84901).
If a given load cell in a piggyback map commands the injectors (either by spoofing air flow signals or direct control) to inject a quantity of fuel that will lead to a (narrowband measured) AFR that is greater or lower than the ECU is programmed to allow, the ECU will retaliate by trimming (adding or subtracting) fuel from those load cells.
The high fuel trims have two undesirable effects (1) they can royally screw up drivability, and (2) they can interfere with any changes made to your WOT tune.
This is because the ECU will determine (by means that are not entirely clear) an appropriate LTFT to apply to the cells that are activated in open loop (WOT).
If this number is relatively high (for sake of argument, let’s say greater than 9%) it may adversely affect the power (run too rich) or safety (run too lean) of your tune. Therefore, it would be desirable to minimize or eliminate all of the LTFT’s BEFORE tuning for optimal power.
More on LTFT’s
Contrary to what some of you may think, there isn’t a single LTFT in closed loop, but MANY. The Toyota ECU creates LTFT’s for small blocks of load cells in its map – I’ve found some evidence that there may be individual LTFT’s for individual cells! (Probably, they are eventually averaged so that you have less variation in the LTFT’s across blocks of cells, but this is all top secret ECU voodoo that few people know about in great detail).
Although you cannot see the Toyota ECU’s map like you can on the EMU (and there are several, not merely a single map), you CAN record all of the LTFT’s in real time while driving, and identify which cell on your EMU map is associated with each recorded LTFT. Then you can make changes to the corresponding EMU cell to minimize or eliminate the trim.
I’ll show you how to accomplish this task step-by-step.
Ideally, when you are done, all LTFT’s will be close to zero (for our purposes, let’s say < 10%, but hopefully closer to %5 or less)*, and the LTFT carried into WOT will be almost zero.
Before you begin, you will need the following items:
1. Laptop and most current version of EMU software.
2. An OBDII scan tool capable of logging ECU data from the OBDII port. I use the Auterra tool with my Palm pilot – for more details go here http://www.auterraweb.com/dynokitsnohotsync.html
3. Ideally, a wideband AFR gauge (although this is not abosolutely necessary to tune out fuel trims, you'll need it for power tuning and for monitoring the car).
4. Considerable patience
5. Go to a professional tuner if you don't know what you're doing. Err on the side of caution. Basically, if what I say makes no sense to you, just pass on these suggestions to your tuner...
Once you have the prerequisite items, here’s what to do before you begin:
1. Go to the parameter menu. Make sure the stock injector value is correct. If you had/have the yellow injectors that value should be 310 and if brown it should be 330. If you have new injectors of a different size, enter in the value for the new injectors you are using.
As to the inj lag time, if you have a value in there that is working for you, just leave it alone for now. If not, this will take some trial and error to set correctly, but I can tell you that the car won't idle properly if the value is too high (idles overly rich) or too low (idles overly lean). High fuel trims at idle are a sign that the inj lag isn't set quite right... As far as I can tell, when warm, it should idle around 14.7 - 15.1 AFR (or a tad leaner) and between 13.0 - 14.0 AFR when cold. More on this later...
2. Zero out the airflow map, at least through 2K in low load. Worthless. All it's doing is throwing things off. I would only mess with this if you are having idle problems due to your intake. Best to leave this zeroed though, IMO [**BUT, SEE NOTE BELOW].
If you are working with an airflow map that has adjustments to the high load cells, I recommend you leave them as they are for now, as they are probably keeping the MAF from maxing out.
I will have additional tuning suggestions added later for what to do if the MAF is maxing out and how to tell when this is happening (hint, if you are logging inj input duty cycles close to 100%, the ECU is not happy with you and you need to adjust airflow voltage readings in the affected cells and or use the boost limiter to clamp the airflow readings!).
3. Datalog your MAF voltage readings and re-scale your Y axis on all the relevant maps based on your voltage. Evenly spaced break points going up by .2 volts is a good starting point, but this will take some experimentation. The range is going to be 1 - 5v.
Likewise, scaling the x axis (RPM's) will take a little trial and error to find the right breakpoints, but evenly spaced intervals, though a good starting point, is probably not going remain consistent throughout the map.
Just be sure to scale all your load-based maps the same way.
Recording and tuning out Long Term Fuel Trims (LTFT)
1. Zero out all the low load (closed loop) cells in the inj map, if you haven't already done so. Again, make sure the airflow adjustment map low load cells are also zeroed out as well [**SEE NOTE BELOW]
2. Reset the ECU.
3. Start the car; get it up to operating temp.
Hook up your laptop and data log RPM and airflow voltage on the EMU. You may have the map trace on if you wish to help focus on specific load cells while driving.
Hook up the OBD II datalogger and record RPM and LTFT bank 1 -- these are the only two ECU variables you care about right now.
4. Drive around for at least 30 minutes (drving around longer is better -- see "HINT" below). Try to hit as many load points -- all in part throttle, closed loop, just crusing around -- as possible on the emanage fuel map. While doing this, record LTFT and RPM on your scantool.
At the same time, have the lap top recording RPM and, if you wish airflow voltage, (really, all you need is RPM). You may have the map trace on if you wish, but it's not necessary.
Note that the LTFT’s that are recorded on the OBD II reader change as you hit different load cells on the EMU map – this is because there are separate LTFT's associated with either individual cells or at least a cluster of cells in the ECU's fuel map.
BTW, also note that the ECU cuts fuel when decelerating (if you have a wideband, you will see the gauge indicate a severely lean condition in decel) -- therefore, don't worry too much about part throttle load cells activated when decelerating -- basically, you are temporarily in open loop and it doesn't seem to affect things much if at all. You can probably leave those particular cells (high RPM, lowest load), zeroed out.
HINT: If you have the time, it's better to drive for several hours (or even wait several days) so that LTFT's stabilize and THEN datalog. When datalogging, it's also worthwhile to record the Short Term Fuel Trims (STFT).
Eventually, the STFTs will minimize in value and should fluctuate back and forth between small positve and negative values.
Once the STFTs have minimized (don't be alarmed by an occasional large one), you know that the LTFTs should be stable, and time to make corrections.
The biggest factor that will affect this is the weather -- the best time to do this is when it's right around the average weather temperature for the time of year that you are tuning (i.e., don't pick the hottest day or coldest night of the year! Ideally, you'd do it on a day with low to moderate humidity and about 75* F.
Either way, you probably need to tweak things once or twice a year -- it's good to check the fuel trims at least once every couple of months).
5. Go home. Bring in the lap top and the OBD II datalogger to review the recorded data from both.
When you review the OBD II data, you should play it back as a graph displaying both recorded values (i.e., RPM and LTFT) at the same time.
It will look something like this:
In reviewing the OBD II data, take note of LTFT's and RPM on the scantool recording.
Pause the play back, and you can select individual data points.
Your goal is to match this OBD II data to the data recorded on EMU in order to locate cells that need tuning on your EMU inj adj map.
By eyeballing the shape of the recorded RPM curve from the OBD II data log, you will be able to easily locate the same RPM/load region on the emanage map that corresponds to the one datalogged with a given LTFT on your scantool.
Then it's simply a matter of selecting the datapoint on the EMU data log that matches the one you've selected on the OBD II datalog.
Observe (Click on thumbnail for larger images)…
Click on thumbnail for larger images.
If you click on an RPM data point in the recorded emanage graph that matches the same spot on your OBDII datalog, you will be able to figure out what LTFT was associated with the corresponding load cell in the EMU inj adj map.
Go look at your fuel map on the emanage. The data point that you clicked on in the EMU datalog will automatically highlight the corresponding cell in your inj adj map.
If the logged LTFT on the OBD scantool that matches the selected datapoint on the EMU datalog graph/inj adj map was negative, subtract some fuel from that cell. If positive, add some fuel to that cell.
If you find you get a wide variety of LTFT's in that same cell, you may need to add another break point in the fuel map for greater resolution.
6. Make small changes to your EMU map, flash it to the EMU, and drive around as you did before, once again recording with the laptop and OBD II datalogger as previosuly described.
Repeat these procedures until all LTFT's are in the single digits (as close to 0.0 as possible).
7. Now comes the scary part: Reset ECU and do it all over again -- you need to do this to help ensure that the LTFT's will always be low even if the ECU is reset -- remember, the ECU is always adjusting itself, so you want your tune to allow that to happen without high LTFT's being created unexpectedlly.
If your tune was good, after driving around for a little while, the LTFT's should stabilizie, and be very close to where they were previously (i.e., low single digits).
Be sure to give it a few hours of driving to ensure that all the LTFT’s have stabilized.
It will always vary a little bit due to ambient temp, but ideally, it will remain in low single digits or close to zero under all operating conditions -- that's the goal!
***NOTE: What's most important is that the LTFT that is carried into open loop is close to zero (mine is < 1%). If you have a few cells where the LTFT is a bit high, but drivability is fine and the WOT (open loop) LTFT is low, you're golden.
To determine your LTFT in WOT (open loop): Floor it and datalog the LTFT. Whatever that number is should remain fairly constant once LTFT's in the rest of the map have stablized.***
This whole process can take hours or even DAYS, and it is one of the main reasons why folks generally hate working with piggybacks.
That said, if you can endure it, eventually you can get the car running very smoothly off and on boost.
*Note on fuel trims. Keep in mind that the fuel trims correspond to a change in inj duty cycle that moves the AFR to a value the ECU will accept.
HOWEVER -- it should also be noted that if you are using larger than stock injectors, the actual effect it has on your output duty cycle will be less than the ECU claims.
In other words, if you are running injectors that are 50% larger than stock, the actual effect of the duty cycle change commanded by the ECU will be less (not exactly 50% less, though...).
The ECU has no idea you are using larger injectors; it's merely additng or subtracting fuel until it sees a narrowband measured AFR voltage it likes. The amount reported reflects the amount of correction ECU "thinks" it has made based on it's mistaken assumption of stock injectors.
Anyway, I'm pointing this out because in the afforementioned example, a recorded LTFT of 5% would probably really be only create a 2-3% correction.
Using the AFR target Map to maintain desired AFR's in WOT
Coming soon! Short version is, by creating a closed loop map on the cells activated in WOT, you will be able to more easily keep your AFR's where you want them even when there are dramatic changes in weather conditions and even if the (small) fuel trim that gets applied to WOT changes slightly.
Further Improving Drivability: Tuning Injector Acceleration Enrichment
Quick inputs to the throttle will result in an abrupt change in the AFR as a large mass of air is ingested. Unfortunately, this may create a momentary lean condition and hesitation off idle. This is corrected by injecting extra quantity of fuel for a few milliseconds. You may also tune this feature with the EMU.
If you are getting hesitation off idle, use the map trace on the injector acceleration enrichment map, and take note of which cells are activated when it hesitates. You'll most likely need to add or subtract fuel to those cells.
Drive around for a while, somewhere where you can stop and start, applying different degrees of throttle to take off -- a big, deserted parking lot would be a good place to do this. This is tedious and will take a while to dial in, but you can get the car to have excellent throttle response with trial and error.
How to Use the Emanage Rev limit Cut Setting
For details, please see this thread http://www.newcelica.org/forums/showthread.php?t=275482
NOTE ON AIRFLOW CORRECTION
If your intake tube has an inside diameter that is larger than the stock 2.5", you might try making a global correction to the airflow map (at least in map cells activated in part throttle). The global correction should be approximately equal to the difference in the diameter of the intake tube from the stock diameter.
Example: The stock tube has a 2.5" inside diameter (i.e., 63.5 mm). If you are using an intake with a 3" inside diameter (i.e., 76.2), that's a difference of 20%. Therefore, you would make a correction of 20% in all of the cells of the airflow map, or at least those that are activated in part throttle (in WOT, especially if under boost, you may or may not want to do this -- I'd determine that empirically).
If you need to make this correction, it should be done BEFORE tuning out any fuel trims or tuning for drivability or power.