I don't understand what you are asking. Are we talking about a device called a MASS AIR FLOW like is used in most Fords? I am not any sort of Harley expert but I have never heard of any of them having a MAF. FWIW the racecar in my sig runs a Ford MAF driven Megasquirt EFI. I designed the control logic in that part if the MS code.

AW

 

I don't understand what you are asking. Are we talking about a device called a MASS AIR FLOW like is used in most Fords? I am not any sort of Harley expert but I have never heard of any of them having a MAF. FWIW the racecar in my sig runs a Ford MAF driven Megasquirt EFI. I designed the control logic in thatsubrutine if the MS code.

AW

 

 

Does the MAP sensor measure the amount of airflow through the throttle body?? Is it Flow or pressure?? What else measures the amount of airflow in the throttle body to tell it how much fuel to get the ratio? Had the piano wire in my 4th gen LT1 Firebird.

Don't get me wrong, I'm just getting my head around this as well. What is the term for the MAP sensors to you?? ( thus the list I was alluding to earlier)

 

Found it.....Manifold Absolute Pressure sensor.

Sorry

 

MAP (in caps) is normally the Mannifold Air Pressure as read by the MAP sensor This is the air pressure in the intake mannifold. The easy way to think of it is 100 KPAis 100% air like when at sea level. 20 is simmilar to 20% air so almost all of the the air has been sucked out of the intake buy the motor like on a high RPM downshift. 40 KAP is what these motors tend to idle at.75 KPA is fairly hard into the throttle.

Map (in small letters) tends to refer to thefuel and or timing charts that define when to bring on the fuel or timing

AFR Air Fuel Ratio remember 12:1 is lots of fuel and 17:1 is real lean. In the Harley world 14.7 (some feel 14.2) is about as lean as you ever want to go and 12.7+/- is rich.

AC Air Cleaner

VE Volumetric Efficiency. The ability of the motor to suck air compared to what theory woud prodict the flow would be considdering the MAP reading in the intake. 100 is no loss in flow thru the intale valve and or the throttle body/Air Cleaner. Exhaust that never got out of the cylinder due to strange things going on in the exhaust will mess with your head on this one. Bigger numbers mean more fuel.

 

Cool.. Thanks whittlebeast.

See I learn something new everyday....And I'm still going to die stupid...lol

 

Rider57...did you get a chance tobreak it down to layman terms for cruiser?? Seems that these IED's are doing a better job than we thought?

Do your homemade IED's run a different resister ( or whichever the teminology) than the Nightriders??

 

This trick is the same on any vehical that runs the cheep narrow band o2s and has nothing to do with on model to the next. Harley or Ford or Chevy... all the same trick.

AW

 

Heywood - this type of EFI does not directly measure airflow. There is no "hot wire" sensor or anything like that. HD uses a SD (Speed Density) type of EFI that measures intake air temperature (the IAT sensor) and intake manifold pressure (MAP sensor), then uses a table of values to calculate the mass of air going through the engine.

Most newer EFI systems directly measure the amount of air going into the engie via a Mass Airflow Sensor. When you make changes to a system that has a Mass Airflow Sensor, it will learn the changes and compensate for the additional airflow via adding more fuel (as necessary). It is adaptive. The target values for AFR are stored within the ECU. Tuning of these systems simply adjusts the target values for AFR (I believe).

The SD EFI HD's run cannot adapt to significant changes in the engine. It relies solely on data stored in "look up tables" within the programming of the ECU. When somebody gets a dyno tune, the tuner will modify the numbers in the various tables to adjust for engine/intake/exhaust modifications. It is truly a custom tune. In closed loop mode, the system can adapt a very small amount in order to adjust for outside temperature and pressure variations. When we throw air cleaners and pipes on our bikes, the values stored in the look up tables are still the same ones as stock (unless a tune has been done of course). The ECU doesn't know more air is actually passing through the engine. It still thinks that (given the measured pressure and temperature) the airflow is stock, so it adds only enough fuel to accomodate for how much air it thinks is going through the engine - BUT, with those pipes and air cleaners flowing more air, there IS more air going through and that means the engine will be running lean.

The IED's simply direct the ECU to choose a set of values meant for when it senses the engine is running too lean (it modifies the signal voltage to basically tell the ECU that the engine is running at 15.1:1 AFR) - therefore adding more fuel to get the AFR back down to the 14.6 or 7 range (as far as the ECU is concerned). Obviously, since we are fooling the ECU, the actual AFR's drop to the 14.2:1 range (on a stock bike). All of this can only occur in closed loop mode.


I was unaware that there is any adaptive tables within the HD EFI system. Somebody with SERT experience would have to confirm/deny that. I do not believe it to be the case (but I could be wrong). As far as I know, the system simply switches over to open loop mode and uses the fixed data programmed into the ECU....