On a fuel injected, closed loop feedback, system... it shouldn't matter at all. Engine operating temperature can definitely affect engine performance however (running too cold, or running too hot), which is a big problem for air cooled motors.

 

Open loop still uses the MAP and Temp sensors to adjust. It just doesn't have that "loop" that is controlled by the o2 sensors for the cruising area that most riders are in 90% of the time that will be adjusted to stoich.

 

I'm not sure I understand your point here. Are you saying that the o2 and temp sensors are not being used to adjust fuel mixture above idle in a closed loop system?

 

google "speed-density tuning" then you will understand.

Why do you think they have temperature and pressure sensor?

The ecm is measuring the density of the air. Once they get the density of the air they can then get the mass of the air. Once they know the mass of the air they can calculate the mass of the fuel required using the AFR programmed in the relevant cell. Or if closed loop a constant 14.6 AFR

(I am sorry that I know all this stuff, but once a bell is rung you cannot unring it)

 

How does knowing the pressure in the fuel system measure air density?

 

keith, I will let someone else explain it to you. The MAP sensor is not measuring fuel pressure.

 

I am saying that an open loop system makes all the same adjustments for elevation and temperature that a closed loop system does. It seemed in your statement that you implied that only a closed loop system would do that.

 

Oh. No. I was only talking about a closed loop system. But, thanks for the clarification.

 

No, harley fi systems do not have a mass air flow sensor, only a manifold air pressure sensor, compensates for altitude. (you don't know wth you are talking about, LOL)

 

I did not say they had a mass air sensor. They have a MAP sensor. They calculate the density of the air and from that they can calculate the mass of the air.