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-   -   R1150 Cold Starting Sequence (http://www.advrider.com/forums/showthread.php?t=846767)

roger 04 rt 12-07-2012 08:54 AM

R1150 Cold Starting Sequence
 
It's that cold time of year here in the Northeast. I realized this week that I had some interesting data on how the Motronic manages cold starting of the R1150s that I haven't seen elsewhere. I took some time and brought it together in a single Excel spreadsheet. The Motronic is quite an orchestra conductor.

Below is a graph that shows how the Motronic MA 2.4 with Pink Coding Plug manages the cold-start process. This chart was derived from some measurements I was making on the Yellow and Pink coding plugs, and it combines data from the GS-911 and the Innovate Motorsports LC-1. It may not be easy to digest at first but have a look at it and then see the comments beneath the chart.

http://www.streamlineleaders.com/ima...rtsequence.jpg

Notes on Conditions
--The motorcycle was cold-soaked overnight and on its centerstand.
--Temperature in my garage was about 48 F.
--Cold Start Lever in the detent position (which is 1.28 open on my R1150RT).
--Battery fully charged, alternator came on-line immediately after start.
--LC-1 pre-powered so that it was measuring AFR at start.
--Closed Loop AFR at Lambda=0.94 which is 13.8:1 (Using Wideband O2 Sensor)
--Motronic MA 2.4 Pink Coding Plug (Yellow Plug may be different)

Comments
AFR: The first 25 seconds is very rich. At the end of the chart you can see it step to 13.8:1 which is when it goes Closed Loop

Injection Time: I have doubled the time because each injector fires twice per combustion cycle. During the first 25 seconds (Start Up Enrichment) the Motronic dumps a lot of fuel into the intake--8 mS at first dropping to 4 mS by the time Closed Loop operation begins. After the first 25 seconds the fuel is gradually reduced as the engine temperature comes up. The injectors are very sensitive to battery voltage during starting. If the voltage is low the injectors don't spray enough fuel for a good start.

Spark Advance: Notice that the advance starts at about 11 degrees where it stays for about 2 minutes to help with the cold engine conditions. Then the advance is dropped into its normal idle range of about 6-8 degrees.

RPM: For the first 2 minutes, the RPM gradually rises, even though the injection time is being reduced, as the engine warms up. Then when the Spark advance is reduced the RPM drops even though the TPS is being held constant. Note that at that 127 second moment, in addition to dropping the advance, the Motronic lengthens the injection time a bit. The RPM gradually rises until the Motronic goes Closed Loop. At that time, RPM and Injection Time are stabilized.

Oil Temperature: I've divided the Oil Temp by 10 so that it fits on the graph. Not much to say except that it rises pretty steadily. At about 5 minutes (300 seconds) the Motronic goes Closed Loop. The Oil Temp is about 115 degrees. I don't know what combination of time and temperature the Motronic uses but it also must sense that the O2 sensor is operating, which it tells by O2 sensor voltage and resistance.

There it is, a symphony of moving parts. A lot has to work properly in order for the Start Up sequence to work well.

RB

mouthfulloflake 12-07-2012 09:00 AM

That initial 11 degrees spark advance and rich fueling sure explain why they are so "punchy" right off idle when cold!

good info as always Roger!

roger 04 rt 12-07-2012 08:01 PM

Quote:

Originally Posted by mouthfulloflake (Post 20197653)
That initial 11 degrees spark advance and rich fueling sure explain why they are so "punchy" right off idle when cold!
!

Yup, and there's a good amount of extra fuel for at least a couple minutes befor closed loop starts happening.

roger 04 rt 12-08-2012 06:09 AM

It's raining, and cold, and the bikes in the garage. Decided to measure throttle opening at various positions after reading in my Rider's Manual that the correct starting procedure is to hold the "Choke" (i know it's not but they call it that in the book) all the way up until the engine starts, then release to Mid position.

Full Choke: 4.16 degrees throttle open
Mid Choke: 1.28 degrees
No Choke Idle: 0.32 degrees

mcstark 12-08-2012 07:19 AM

Quote:

Originally Posted by roger 04 rt (Post 20203895)
It's raining, and cold, and the bikes in the garage. Decided to measure throttle opening at various positions after reading in my Rider's Manual that the correct starting procedure is to hold the "Choke" (i know it's not but they call it that in the book) all the way up until the engine starts, then release to Mid position.

Full Choke: 4.16 degrees throttle open
Mid Choke: 1.28 degrees
No Choke Idle: 0.32 degrees

Yup, that's the correct procedure. If the TB's are synced and the valves in good stead, she will start right away. My 1150GS has a lumpy idle and it I try to blip it, she'll stall. So, now I start it and leave it the hell alone!

Interesting data you've gathered. Thanks for taking the time to do this!

roger 04 rt 12-08-2012 07:45 AM

Quote:

Originally Posted by mcstark (Post 20204237)
Yup, that's the correct procedure. If the TB's are synced and the valves in good stead, she will start right away. My 1150GS has a lumpy idle and it I try to blip it, she'll stall. So, now I start it and leave it the hell alone!

Interesting data you've gathered. Thanks for taking the time to do this!

Have a look at this thread, Alternator Start-Up If for any reason your battery voltage is low you'll get that lumpy idle. It may not be the case for you but I stumbled across the low voltage and alternator start issues while I was taking this data.


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