Got a GS-911 in the mail

[Capt. Blackadder]

Howdy folks,

As you may or may not have noticed I've been pretty much AWOL from the board for the past few months. Having two young boys kind of hijacks all your time so I haven't really been anywhere on the bike or done anything noteworthy, hence the silence. However, I did receive a GS-911 diagnostic device in the mail a couple of days ago and I've been putting it through its paces on my R1150R. Apparently all is well, electronics-wise, which I admit was a bit surprising... and perhaps somewhat disappointing! I was hoping I could clear something up, maybe one little fault code or some such, but nothing so far.

Anyhoo, it's a neat little gadget and I enjoy playing with it just like my Power Commander. I'll bring it to the next local Tech Day, whenever that is.

[vintagemxr]

Welcome back, Baldur. I'm sorry to hear your bike is so healthy. Money spent on good diagnostic tools seems a bit wasted when nothing found to be wrong. Sort of like getting a physical at the doctor and discovering you are well and going to live a lot more years. Some bad news would add real value to the experience!

the other Doug

[Tassie Devil]

G'day Captain,
Nice to see you back....

Cheers,

JQ.

[DarthRider]

Hey Baldur, sorry you're having probs.
Tell us about your experience with the Power Commander on the 50R.
I didn't even know they made one for that bike.
We miss you dude!

[Capt. Blackadder]

Howdy folks,

I've been playing around some more with the GS-911 from time to time, for example looking at the live data coming in from the Motronic and all the sensors. One thing struck me as odd... according to the GS-911 the ambient air pressure stays at 968.24 millibar, measured here in my garage, regardless of temperature or weather conditions. I'm no scientist or meteorologist, but I thought that reading was supposed to change at least a little, given different temperature or weather. Any input from more knowledgeable folks 'round these parts?

[Sir Limpsalot]

I didn't have a clue, so I googled it. And came up with this..

http://en.wikipedia.org/wiki/Ambient_pressure

Which seems to suggest it does change with the weather, but (if I read it right) not by much. It seems it changes with altitude, but if you're always checking it in your garage..

[Deans BMW]

Baldur, ride your trusty steed up here, bring your GS-911 and check it here at 6,300 ft elevation.

[jamming]

Baldur, here we go, if I lose you just call me.

Atmospheric pressure as it relates to mechanics IE Aircraft, automotive, motorcycle, etc, is set at the standard of 14.69 PSI at sea level or 1012.84 millibars at sea level. In the case of fuel injection as it pertains to your motorcycle a standard must be set in the ECU for fuel metering purposes. Besides the standard is only set so that Air Density can be measured. I know what your thinking, how in the heck does the ECU measure Air Density? The GS-911 is measuring IS measuring ambient air pressure at your house, its just that the temp has so little affect its not sensitive enough to measure the minute changes.

Fuel injected engines have a MAP (manifold absolute air) sensor that provides the difference between the vacuum of the intake manifold and the ambient air outside and calculates the air density. Thus the ECU can use that calculation to meter the fuel. Some engines may use a MAF (mass air flow) sensor that calculates the mass of the airflow entering the intake side but in reality it still is measuring air density.

All of these sensor measurements(MAP/MASS/O2) and the ECU are trying to accomplish is to make sure that the engine has the ideal stoichiometric (air/fuel)ratio. The ambient air pressure really doesnt come in to play. That's about as clear as mud huh?