EFI Myths answered.

Davo said:

Mark_Donovan said:

Davo I'm making a list to bend their ear when I call back. If the MAP sensor is only utalized below 6% throttle, maybe the "don't touch the throttle 5 min initialization' is when the map readings make any difference. Perhaps at idle it provides a more stable reading. Have we decided if that reading could be perceived to change based on barometric pressure?

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I can understand the info you found in Wikipedia. When the Throttle is wide open (WOT) the Map Sensor which is connected to the inlet manifold can get a better reading of Atmospheric Pressure because there is a “clearer” path to the outside air with the butterfly in the Throttle body open all the way. But I cannot get my head around the MAP sensor getting an Atmospheric Pressure reading when the Butterfly is closed and the air is coming through a very small hole.

That Wiki thing you found pretty much said at sea level and wide open Throttle the MAP sensor should see about 14.7 psi and half that (7.3 psi) at a high elevation.
If you apply that Wiki theory to the Husaberg idling with the Throttle Butterfly shut would the MAP sensor see that difference of 7.4 psi (14.7 – 7.3) at different elevations, when there is already some vacuum in the inlet manifold. I don’t know the answer to that but I would guess no. I can’t even test that on my Autronic in my boat as it is only ever at Sea Level.

The real question to ask the KTM Techs is what is the Khein EFI recalibrating?
It can’t be the Fuel Map as it has no Oxygen Sensor to check any Air/Fuel Ratio measurements.
It can’t be Altitude as the Map Sensor is behind the Throttle Body in the inlet manifold and the Butterfly is shut so it would be impossible to get an accurate reading. (I could be wrong on this).
It actually can’t be much of anything at idle as the EFI would need to read it’s engine sensors at a particular Engine RPM and Load (Load being MAP sensor presure or TPS Position) to even know what to change.
You might as well ask them does the Khein EFI, as it is set up in the Husaberg, make any compensation for Altitude. I am guessing no, as it uses the TPS as the Load axis on the Fuel map after 6% throttle opening and it can’t get an accurate reading from the MAP sensor for Barometric Pressure before the engine starts, as the engine is spinning before the ECU receives power so there is already vacuum in the inlet manifold.

I am guessing the instructions that the dealers get to do this “Burn in” is based on a closed-loop EFI system as used on previous KTM Khein EFI Bikes with:
* Oxygen sensors that can provide feedback to the Fuel Map table after the engine has warmed up (might explain the 5 min period).
* Possibly a second type of pressure sensors to measure barometric pressure.
* Elaborate Throttle Bodies with Electronic butterflies and idle up solenoids. The Husaberg is a plain and simple Throttle body with no Electronic gizmos in it that are controlled by the Khein EFI ECU.
* Possible Knock sensors.

In summary I believe the Khein ECU as it is setup in the Husaberg is setup in an open loop EFI mode that cannot recalibrate a Fuel or Ignition map because it has no useful information to do this, especially at idle. I reiterate, Temp Sensor and Air Temp Sensor should just be a Multiplication factor on the base Fuel and Ignition map settings which can be done on the fly at any engine speed or load, and not by sitting for 5 minutes at idle.
Reminds me of when I was younger and raced a 350 Chev in my ski race boat. Timing was set by making a mark at 30 Degrees on the flywheel and reving the engine to 3,500RPM and setting the timing at 30 Degrees. Jets in the Holley were set by holding the boat flatout (we didn’t have WOT acronym back when I was young) at 6,200RPM for a few minutes, turn the ignition off and pull out the plugs and making a judgment on what jet sizes to run based on plug color. Everything "of importance" was changed at the speed we would run the engine at not at idle.

In the 1 year I have owned my FE570, I have never let my bike idle for 5 minutes and never will. Again, I am happy to be proven wrong and by all means let me have it with both barrels when you correct me. I am here on UHE to learn.
What is your favorite drink Mark? I love your southern accent that I heard on a post you did ages ago with some children riding with you.

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RedRockRider said:

To help you understand this the MAP sensor is a Absolute pressure sensor. You are trying to think in terms of PSIG which is Atmospheric pressure +. 14.696 psia = 0 psig Dealing with FI air density values are done in absolute pressure. In fact, the MAP sensor can accomodate changes in elevation based on the absolute pressures being monitored.
Regards,
Thomas

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Mark_Donovan said:

I may already have egg on my face for blindly repeating the words of the Tech adviser for the brand. I should have added a disclaimer to the first post. I am intrigued by the subject and want to get to the bottom of it.

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Davo said:

RedRockRider said:

To help you understand this the MAP sensor is a Absolute pressure sensor. You are trying to think in terms of PSIG which is Atmospheric pressure +. 14.696 psia = 0 psig Dealing with FI air density values are done in absolute pressure. In fact, the MAP sensor can accomodate changes in elevation based on the absolute pressures being monitored.
Regards,
Thomas

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Hey Thomas,
I aggree a MAP sensor can accomodate changes at elevation, but can the MAP Sensor in the Husaberg see different air density based on elevation when idling? The MAP sensor doesn't have a clear shot at the Atmosphere with the Throttle body closed.

And why does a Husaberg need to idle for 5 minutes to work out elevation? If in fact that is what it is working out while it is idling.

It just frustrates me this "letting your bike idle for 5 min" thing to let the EFI adjust, I can't understand what it does.
No car dealer has ever told me anything like this in any of my Fuel injected cars I have purchased. Imagine sitting around the boardroom in KTM when the LDC was in design phase, the EFI team presents, "Oh yeah EFI is all taken care of, you may need to sit around for 5 min idling when you go up a big hill but that should not be an issue as most bike people that ride together are all friends and would fully understand and not make fun of the Husaberg having to do this."
I guess it could have happened as the Map Switch got though into the production bike somehow. What were they thinking there? Something straight out of Luney Tunes that little gem of a Switch.

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RedRockRider said:

As for the 5 min, they could be making sure the bike us up to operating temp before saving any values or setting of "Trend Data", dunno. The MAP sensor works the same as a RAD guage (relative air density). As you know, as one goes up in altitude the air becomes less dense so to speak. Even with the butterfly valve closed and the bike idling, the map sensor can still detect the differences air density/pressure based on the amount of air going by.

The bike has a lamda sensor in the exhaust to make sure the projected fuel amount required for combustion is correct based on the exhaust gas analyzing. Prolly common knowledge and you already knew that bit. I am new to these bikes and think a practicality argument for fuel injection should take place. Awesome bikes though.
Regards,
Thomas

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Davo said:

RedRockRider said:

As for the 5 min, they could be making sure the bike us up to operating temp before saving any values or setting of "Trend Data", dunno. The MAP sensor works the same as a RAD guage (relative air density). As you know, as one goes up in altitude the air becomes less dense so to speak. Even with the butterfly valve closed and the bike idling, the map sensor can still detect the differences air density/pressure based on the amount of air going by.

The bike has a lamda sensor in the exhaust to make sure the projected fuel amount required for combustion is correct based on the exhaust gas analyzing. Prolly common knowledge and you already knew that bit. I am new to these bikes and think a practicality argument for fuel injection should take place. Awesome bikes though.
Regards,
Thomas

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Hey Thomas,
The 2010 models don't have a lamda sensor in the exhaust. The 2009 models do but I am led to believe from previous posts they are not active. In fact some users on this forum have disconnected them.

Thanks for correcting me I did not think the bike could accurately detect atmospheric pressure with the butterfly closed and the engine idling .
You have seen this on an EFI system first hand? Like a readout from ODB or Motec or Halltech or Khein etc? I ask, as I know Autronic can only do it when the ignition is on the the engine is not spinning. Autronic has 1 chance at getting a reading before the engine starts.

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