ADVrider

Go Back   ADVrider > Bikes > GSpot > GS Boxers
User Name
Password
Register Inmates Photos Site Rules Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
Old 12-07-2012, 08:54 AM   #1
roger 04 rt OP
Beastly Adventurer
 
roger 04 rt's Avatar
 
Joined: Nov 2011
Location: Massachusetts
Oddometer: 1,934
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.



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
roger 04 rt is offline   Reply With Quote
Old 12-07-2012, 09:00 AM   #2
mouthfulloflake
Not afraid
 
mouthfulloflake's Avatar
 
Joined: Aug 2008
Location: N.W. Arkansas
Oddometer: 15,278
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!
__________________
In dog beers, I've only had one.
Charter member: T.O. club.
Tilt your head, not the taco.
mouthfulloflake is offline   Reply With Quote
Old 12-07-2012, 08:01 PM   #3
roger 04 rt OP
Beastly Adventurer
 
roger 04 rt's Avatar
 
Joined: Nov 2011
Location: Massachusetts
Oddometer: 1,934
Quote:
Originally Posted by mouthfulloflake View Post
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 is offline   Reply With Quote
Old 12-08-2012, 06:09 AM   #4
roger 04 rt OP
Beastly Adventurer
 
roger 04 rt's Avatar
 
Joined: Nov 2011
Location: Massachusetts
Oddometer: 1,934
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
roger 04 rt is offline   Reply With Quote
Old 12-08-2012, 07:19 AM   #5
mcstark
Oilhead convert
 
mcstark's Avatar
 
Joined: Sep 2008
Location: Bflo, NY
Oddometer: 964
Quote:
Originally Posted by roger 04 rt View Post
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!
__________________
Regards,
Mark

2003 BMW R1150GS
mcstark is online now   Reply With Quote
Old 12-08-2012, 07:45 AM   #6
roger 04 rt OP
Beastly Adventurer
 
roger 04 rt's Avatar
 
Joined: Nov 2011
Location: Massachusetts
Oddometer: 1,934
Quote:
Originally Posted by mcstark View Post
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.
roger 04 rt is offline   Reply With Quote
Reply

Share

Thread Tools Search this Thread
Search this Thread:

.
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


Times are GMT -7.   It's 05:54 PM.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright ADVrider 2011-2014