Keep us posted!

 

I can't answer your GOOD question, but I would be SO happy to see evidence if you can actually produce it, good god I'd like to put some of this to rest. But it won't solve the entire issue - we need to know the limits of the adaptive learning, and then to put it to test against a good dyno tuner, if even possible! I know I'm a PITA asking so many questions but the mystical nature of this needs to be shattered with proof.

 

It's because in Open Loop conditions (usually WOT throttle or very heavy acceleration/load) the engine needs to run at peak power and maximum performance thus the programmers do not want anything changing the programmed tables within reason. Think of a EFI car in Open Loop like you would a Carbureted car...because they act just the same, no adjustments are being made. EFI has better gas milage because of the ability of Closed Loop programming to maximix fuel ecconomy rather than power. At WOT, you just want power, fuel milage be damned!

LTFTs can allow fuel to be added to or taken away based on how the engine has ran in other conditions but they don't need constant readings from the O2 sensors...one reason is because they will be lagging too far behind what is happening RIGHT NOW under those conditions. This is why we tune to 0 LTFTs...because then we know we have the fueling right for what we're trying to accomplish.

The adaptive learning "limits" I don't think we'll ever really know. LTFTs in the Grand Prix will go from -14 (pull a lot of fuel) to +14. I've never learned just how much fuel each number represents as far as AF. What I do know is if you take a car that is meant to run at 0 LTFT and change that LTFT to -12 that it's enough to chip a piston during a five second WOT run. Ask me how I know...LOL

Funny thing is, we haven't even gotten into VE table values themselves or how they relate to Injector Pulse Width and Injector size...there's another fun filled fuel topic!

 

The following information is based on conversations with our HD contact, our Delphi contact, HD Service Manuals, HD SEPST Documentation, TTS Documentation, and my own synthesis of years of experience with thousands of bikes.

It is probably not enough for some that may want a written explanation from HD or Delphi, but hopefully it will be of assistance to some in understanding HD Fuel Injection processes.

There may be some confusion regarding the term Adaptive Learning.

There are two ways the Electronic Control Module (ECM) adapts:

First, let's look at what input the ECM receives, so we know what it has to work with to make any "Adaptive" changes-

1. CKP - (Crankshaft Position Sensor): Basically this sensor monitors the crankshaft speed and position. The ECM uses the inputs from the sensor to determine what stroke the engine is in so it can deliver the fuel and spark at the desired time...

2. MAP - (Manifold Absolute Pressure): The ECM uses the inputs from this sensor to help calculate how much air is entering the engine.

3. IAT - (Intake Air Temperature): The ECM uses the inputs from this sensor to help calculate how much oxygen exists in a particular volume of air..

4. ET - (Engine Temperature): The ECM uses the inputs from this sensor to determine engine temperature...

5. TP - (Throttle Position): Provides input to the ECM as it reacts to throttle shaft rotation... These signals indicate throttle position, if the throttle is opening or closing and how fast it is opening and closing...

6. VSS (Vehicle Speed Sensor): Provides input signals to the ECM to indicate the speed of the motorcycle...

7. BAS (Bank Angle Sensor): If the motorcycle leans over more than 45 degree's from vertical... If the ECM receives this input for more than one second it assumes the motorcycle has fallen over and shuts down the fuel management and ignition circuit...

8. O2 Sensor: The are switching type sensors (stock HD's are narrow band sensors used in closed loop systems) they provide inputs to the ECM based on the amount of oxygen is being sent in the exhaust system...

9. ISS (Ion Sensing System): It detects detonation or engine misfire in either the front or rear cylinder by monitoring the electrical energy at the spark plug following every time spark...If an abnormal level of energy is detected across two or three spark firings the ECM responds by retarding the spark timing in the affected cylinder as needed to eliminate it...

All of the above sensors give data to the ECM to allow it to ADAPT to the ever-changing environment. This is one of the ways the ECM ADAPTS.

The second way the ECM ADAPTS is via "Adaptive Fuel Value" or "Adaptive Fuel" (reference the HD brand Tuners to see that this is a feature of the ECM) This is commonly what is referred to as the Adaptive Learning Mode.

Adaptive Fuel is known generally in the EFI world as Long Term Fuel Trim (LTFT).

When in closed loop the ECM uses the information from the above list to calculate airflow, load, temperatures, throttle position, to adapt and maintain the targeted AFR in the closed loop section of the map.

It then uses the o2 sensors to determine what the AFR actually is. If there is a difference, the ECM makes an adjustment real time to the closed loop map, AND stores the difference in an "Adaptive Fuel Value" cell for future use in Open Loop. (again, reference the HD Brand Tuners to verify that there is an Adaptive Fuel Value" that is stored in the ECM and that is constantly changing)

Over time (sources vary between 30-120 minutes of riding) the Adaptive Fuel Value develops a correction profile that is applied to each cell of the map in open loop.

To put it another way, when the ECM sees the closed loop values constantly being richer than expected (like when using an XiED family product), the Long Term Fuel Trim (Adaptive Fuel Value) is increased, resulting in a richening up of the open loop values.

I hope this helps those looking for a clearer understanding of the HD EFI.

It is NOT meant as any dis-respect to anyone, nor is it an indication that I want to argue or get into any long drawn out conversations about the subject.

I think I have pretty much shared the depth of my knowledge on the subject in this post.

 

Just to wrap my head around it and merge what I know about the GM system with the Harley system...the "adjustment real time to the closed loop map" is what I think of as STFT, correct?

 

Yes. It is adjusting the fuel on the fly based on the input from the o2 sensors.

 

Im installing my exhaust this week and planned on ordering my air cleaner kit and fuel moto tuner this week but man am I confused now....what the hell to do?? lol on a 2013 FLS Slim

 

Well I followed most of this 'I think, the ECM can make adjustments but only withinthe range of the pre-set map and that map is set to lean, so within the map it can change how much fuel is being added at a given time from maybe the last time depending on all the sensors but still never to exceed the limits of the map (if that makes any sense).

By adding a XIED device that tricks the ECM to read a lower number forcing the ECM to add more fuel than normal, it takes it from running too lean to a more of a richer setting.

My understanding of a tuner is that it ignores the lean map already preset on the ECM and adds another map that has a wider range when it pertains to Fuel and air mixtures therefore allowing the mixture to be richer (thus, better for the motor). That is what I came away with after reading this.. but it wouldn't be the first time I read something wrong

 

A "reflash tuner" overides the original map with a new one.

 

Hi,

Is 14.7:1 AFR to lean anyway? Or 15 or 15.5? For fuel economy, mileage etc those values would be okay?tuners want performance which is more fuel?

If I run Tank at freeway riding I get about 340km from 98 octane, if I smash it around the streets and freeway WOT my mileage goes down 60-80km as I get that power on

All interesting stuff
Thanks
Mirrmu