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Discussion Starter #1
I'm hoping someone could help me figure this out. My bike stalled a few days ago and wouldn't start. I took the tank off and replaced the fuel filter. It ran fine after that for 200 miles. It stalled then wouldn't start. Put another filter on it. It ran fine for 100 miles then wouldn't start. Took the tank off, looked at the filter and hoses. Looked fine. Plugged everything up. It started and ran fine for 50 miles then wouldn't start. Tried unplugging everything then starting but wouldn't start. Took the tank off, pulled the pump out, looked at it, replaced then ran 25 miles. ?????? I know I have a sensor problem because it runs very rich while warming up and the fan kicks on when cold but I think that problem is unrelated to my fuel problem.
 

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I'm hoping someone could help me figure this out. My bike stalled a few days ago and wouldn't start. I took the tank off and replaced the fuel filter. It ran fine after that for 200 miles. It stalled then wouldn't start. Put another filter on it. It ran fine for 100 miles then wouldn't start. Took the tank off, looked at the filter and hoses. Looked fine. Plugged everything up. It started and ran fine for 50 miles then wouldn't start. Tried unplugging everything then starting but wouldn't start. Took the tank off, pulled the pump out, looked at it, replaced then ran 25 miles. ?????? I know I have a sensor problem because it runs very rich while warming up and the fan kicks on when cold but I think that problem is unrelated to my fuel problem.
Initially, I would also go for a blocked tank-vent AND-OR charcoal canister plugged (they are related). HOWEVER the fact that you hear the radiator fans run when engine is cold makes me suspect the engine coolant sensor. This could create confusion so that the EFI system makes the mixture too rich (in particular when engine is already warmed and does not need such rich mixture).

You may just have a bad contact at the coolant sensor connector OR a defective sensor.
The engine temp sensor used by the fuel-management system (Motronic) is located into the rearmost cylinder head (cylinder #4). When/IF the EFI system see a abnormal value (Zero OHMS or infinite resistance), it goes into a fail default mode and assume the engine coolant temp to be 80 celcius (175 F) and the radiator fans will be run full time (as soon as you turn ignition ON).

See this Picassa photo album that explain in pictures (and some text attached to some pictures) how you can test "roughly". Pictures done on a K1200RS, so on your K1200LT there is a bit more fairing to remove - sensor, wire and connector is located at same place for K1200LT of 2005+ (earlier model have connector a bit lower).
https://plus.google.com/photos/101489741192933663432/albums/5715782307964672065


Keep in mind that these temp sensor do NOT fail often, so this is not the most probable cause - has any work been done recently in area of this sensor connector?

**** IMPORTANT: Ignition should be OFF while doing these OhmMeter tests (you are only testing resistance of the sensor).

---------------------------------------------------------
TEMP (in celcius) -vs- resistance (Ohms) for various cases:
---------------------------------------------------------
8 .......... 4000
10 .......... 3880
14 .......... 3290
20 .......... 2570 (20C is roughly 70 Farenh)
25 .......... 2130
30 .......... 1760
35 .......... 1462
45 .......... 1049
55 .......... 727
65 .......... 540
75 .......... 392
85 ..(thermostat opens).. 296
95 .......... 229
105 ..(fans activated temp).. 187
 
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Discussion Starter #4
Thanks for the very informative reply. Might be getting somewhere because my fan is running full time when it quits and takes a long time quit running. I don't understand why the bike restarts after I pulled the tank off. If I do it quick enough the fan is still running. I think it is in default mode. I guess default mode will shut the bike down until it resets. I removed the canister the first day I bought it.
 

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Thanks for the very informative reply. Might be getting somewhere because my fan is running full time when it quits and takes a long time quit running. I don't understand why the bike restarts after I pulled the tank off. If I do it quick enough the fan is still running. I think it is in default mode. I guess default mode will shut the bike down until it resets. I removed the canister the first day I bought it.
I always publish the simple "OhmMeter method" because not everyone has a GS911 (or want to spend $$ at dealer to troubleshoot these problems).
If you can get access to a GS911, this is a better method as you can see the engine-coolant temp data in "real-time" while the engine is running on center-stand (using a Yellow GS911). With the newer RED GS911 (WIFI enabled), you can log data into its own memory while you ride and download the data into a file after.

Both of these method (center-stand run or a full ride) will help confirm what the EFI system is seeing from the coolant temp sensor in various conditions. Real-time data is useful to see any abnormal fluctuation that would indicate a potential bad connection, damage sensor wire (or a bad ground caused by a damaged wire). In addition, the real-time data log will allow to track when the radiator-fans kick ON or when they went OFF.

Many members here have a GS911, so you may find someone in your area.

P.S.: even if you have already removed the canister, do NOT assume the 2 vent hoses coming out of lower fuel tank are clear - one might be clogged by debris.
 

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Discussion Starter #6
Thanks! For the replies. Trying to keep a trip to the dealer on the backburner.
Wanting to learn everything I can about this bike. Don't think I could go back to riding anything else regardless of the issues
 

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Discussion Starter #9
Thanks! Auburn GA is correct. I'll probably just purchase one since I buy used bikes and don't mind working on them
 

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Thanks! Auburn GA is correct. I'll probably just purchase one since I buy used bikes and don't mind working on them
Tom I live in Sugar Hill and i have a GS911 WiFi so if you need to hook one up, we can possibly get together and do some deeper checking. PM me if you want to borrow mine.

Gordon
 

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Rod Man......
Have you tried riding with the gas cap loose?
The cap is not vented, so if you're having a fuel starvation issue due to a vacuum in the tank........loosening the cap a bit should relieve the symptom. (stalling)
 

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Discussion Starter #12
Thanks Gordon! I might need to borrow it. Good to know your nearby. I have rode with the cap loose to rule that out. I'm going to tinker with it a little today
 

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Have you noticed if you hear the fuel pump run when you turn on the ignition when it is failing? If the fans are running full bore even when it is cold, it may be difficult to hear. You might be able to get some meter leads on the plug to see if it is running. Take it out with the side panels off :) instead of having to pull them by the road side.

Not sure if there is an over temp shut down or not. Sailor would know.
 

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Discussion Starter #14
Not sure if the pump is running when it shuts down. If it does have a shutdown mode it probably isn't running. Maybe disconnecting the battery would've been an easier reset if that was the culprit. Had no idea these bikes were engineered this way. I should've purchased a gs911 the day I bought it
 

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....
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Not sure if there is an over temp shut down or not. Sailor would know.

Not sure if the pump is running when it shuts down. If it does have a shutdown mode it probably isn't running. Maybe disconnecting the battery would've been an easier reset if that was the culprit. Had no idea these bikes were engineered this way. I should've purchased a gs911 the day I bought it
On all K1200 brick-engine (K1200RS/GT and K1200LT), the BOSCH Motronic ECU has 2 trigger temp that are hard coded:
1) The radiator fans starting point (105 C / 221 F or roughly 187 Ohms resistance)
On a 1999-2004 USA model like yours (1st generation dash), with all systems are working normally, when the rad-fans start, the needle of coolant gauge on dash should be about HALF-WAY between middle-white line and red-zone

2) The Engine Temp Warning light on dash goes ON (115 C / 239 F or roughly 143 Ohms resistance)
If the fans are doing their job and the coolant system is full and working properly (clean rads), this warning light should NOT appear while engine is running. When you turn ignition ON, before starting engine, you can see if the Engine Temp Warning light on dash is working.

Although I normally test every assumption, I have NEVER tried to simulate a very hot engine by cheating the resistance coming from the engine coolant sensor. HOWEVER, based on every owners manual published for all K1200 "brick-engine", I would assume that there no auto shutdown built-in. Every version of these manual says the same thing:
---- Quoting from Manual ------
If the coolant temperature warning light comes on, stop the engine and allow it to cool down. Check coolant level in the expansion tank. If the expansion tank is full, but
the warning light remains on, or if coolant consumption is excessive, consult a specialist workshop, preferably an authorised BMW motorcycle dealer.
----- End of Quote -----
 

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based on every owners manual published for all K1200 "brick-engine", I would assume that there no auto shutdown built-in. Every version of these manual says the same thing:
Thanks Sailor. That is what I suspected the answer would be but had never heard it or read it anywhere.

A very strange issue indeed. I suspect 2 issues are at hand then as does Tom. One for the fans and temp sensor and this other issue of cutting off. If it was the fuel lines inside the tank, they would be obviously broken or split.

Sailor, have you ever seen a bad fuel pressure regulator on an LT ? I had one on one of my trucks and it would behave like this. Driving along and then the car would stall and not start. Some time later, it would start and run fine. I finally pulled the tank and found a big dent in the regulator probably from someone banging on it prior to me getting the truck.

Possibly just disconnecting the fuel lines would relieve the pressure and allow it to reset. Just guessing though. The symptoms fit.
 

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Gonna order a GS911. Thinking about this one Amazon.com: GS-911 Diagnostic Tool for BMW Motorcycles - USB Enthusiast Version - Services 10 BMW Motorcycles: Automotive unless someone points me in a better direction. One with WiFi would be great but not really necessary
There are a few limitations with this USB-Yellow unit that do NOT apply to your K1200LT, so these limitations are not an issue for the moment. For your K1200LT, this is the best value / cheapest version as long as you have a Windows-based PC (will not work / interface with APPLE computers).

HOWEVER, if you plan in the future to buy a more recent BMW model like the K1600 or the R1200 water-cooled, then you would be better served by spending a bit more for the more recent RED WIFI model.

P.S.: the AMAZON link you gave is correct and is the one being sold by the very good folks a BeemerShop. Do no buy some of the other cheap / unsupported copies out of China (mainly being sold on EBAY).
 

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Thanks! I might eventually get a 1600 in a year or so. Not sure.
For more recent models, you would absolutely need a newer RED-WIFI 2nd generation GS911, as the 1st generation YELLOW unit will NOT work on these. BMW changes the "rules-of-the-game" in these newer bikes, so the folks at HexCode had to come out with something new ;-)

Read at least 1st paragraph in this info page on the GS911 (Hexcode) web site:
GS-911wifi info ? HEX Code
 
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