Author Topic: Help! k11 shuts down still after 20 minutes? Spark good, fuel filter changed.  (Read 9330 times)

Offline Popetrout

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Pump works good, plugs are dry though, is there some sort of emergency shut off for overheating, can't figure this out  got fuel at the rail.  The radiator cap is bad I think because when I removed it the  hose uncollasped when cold, could a bad thermostat be causing it to shut down when it warms up, the temp gauge has been reading at redline off and on in city driving.


Offline Chaos

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a bad Hall Effect Sensor can do that.  Here's an article on troubleshooting it ...  http://www.ibmwr.org/ktech/intermittent-cutout.shtml
  • sw ohio
1987 K75S    VIN 0231
Original owner, Original litter
200,000 miles (plus or minus) and 5 paint jobs
sold 6/23
2023 Ural 2WD sidecar (BMW's bastard step child)

Offline Popetrout

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it's got good spark so it doesn't sound like the problem

Offline Motorhobo

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The radiator cap is vented, and the brass screen clogs up, causing vacuum issues that result in shutdown. This has happened to me a couple times over 15 years. I don't know of a way to clean or replace the screen. New OEM radiator cap is needed unless someone else here has an alternative or knows how to unclog the screen. Last time it happened I cleaned off the old and new one and blew thru them just by pushing my lips up against them -- the new one passed air and the old one didn't.

That might not be your only issue but if air isn't passing thru it, you will need a new one no matter what.
1994/1995 K75 ABS Frankenbike: original engine 136k miles, frame from Gary Weaver (RIP), 173k miles -- Current Odometer: 198k miles
1994 K75 since 2013, 82,000 mi (19k mine) w/California Sidecar Friendship II Sidecar & Black Lab 'Miss B' - RIP

Past: 1974 Honda 550/4 (first bike), 1994 K75 (sold), 1995 K75 ABS (parts bike), Sidecar Dog & Best Bud 'Bo' - RIP

Offline johnny

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if thats my motobrick... i would do this...

1... backspin starter maintenance...
2... clean under tank 4 pin connector...
3... clean motronic contacts...
4... clean the battery hot and all battery grounds...

give it a go... if it goes... there you go... if it doenst go... at least you did some maintenance that you were gonna have to do anyway...

j o
  • :johnny i parks my 96 eleven hundert rs motobrick in dodge county cheezconsin  :johnny

Offline Motorhobo

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The radiator cap is vented, and the brass screen clogs up, causing vacuum issues that result in shutdown. This has happened to me a couple times over 15 years. I don't know of a way to clean or replace the screen. New OEM radiator cap is needed unless someone else here has an alternative or knows how to unclog the screen. Last time it happened I cleaned off the old and new one and blew thru them just by pushing my lips up against them -- the new one passed air and the old one didn't.

That might not be your only issue but if air isn't passing thru it, you will need a new one no matter what.

Actually what I wrote is inaccurate -- the clogged cap can lead to overheating not shutdown. But if it is clogged replacement is the only remedy I know of.
1994/1995 K75 ABS Frankenbike: original engine 136k miles, frame from Gary Weaver (RIP), 173k miles -- Current Odometer: 198k miles
1994 K75 since 2013, 82,000 mi (19k mine) w/California Sidecar Friendship II Sidecar & Black Lab 'Miss B' - RIP

Past: 1974 Honda 550/4 (first bike), 1994 K75 (sold), 1995 K75 ABS (parts bike), Sidecar Dog & Best Bud 'Bo' - RIP

Offline rbm

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it's got good spark so it doesn't sound like the problem
I wouldn't discount the bad hall sensor off-hand because you have a good spark.  The signal from the hall sensor is required by the ICU and, if not present, it kills the engine.  The hall sensor may function normally when at ambient temperature but can fail at elevated temperatures, just when the engine has warmed up.  Good advice to follow the diagnosis in the IBMWR link to which you were referred.

If your hall sensor diagnosis fails to point to bad hall sensor, another possibility could be the temperature sensor in the cooling system.  Read through this thread for more information.  This is plausible because you don't mention in your symptom list whether the fan comes on when the needle of the temp gauge starts to approach the redline.  If you don't hear the fan, it is possible that a bad temp sensor is not signaling the temperature relay to start the fan (or possibly the fan is broken).  Have you tested the fan for correct operation?
  • Regards, Robert
Toronto, Ontario

1987 K75 - Build Blog @http://k75retro.blogspot.ca/

Offline Popetrout

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thanks for the information, I really appreciate it!  Can't wait to go riding before the snow flies.  Now my bike will not start after the last episode, the fuel injectors aren't getting power in my best estimate, checked the connection to the computer and it's good.  So maybe it is the hall effect sensor?  I"ll study up on it and the motronic.  Fan is good. 


Offline Scott_

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On an 1100, another overlooked item.......................  side stand switch. Can be bypassed easy enough for diagnostics and testing if needed.
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1995 K1100LT 0302044
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1997 K1100LT 0302488 (R.I.P.)
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"One who does not ask questions is ashamed to learn" Danish proverb

Offline David_S_Walker

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Hello,

Mine did this when I first got it. When it stopped there was a strong smell of fuel like it was over fuelling. Eventually go so bad that it would not run at all. Turned out to be the water temperature sensor that tells the ECU it is warm now so you can slacken off the fuel delivery.... It is the inaccessible one and not the one that feeds the gauge. Changed this and all was well.

Maybe worth swapping as they are relatively cheap compared to the HES.

Best regards,

David
  • Kent, SE England, United Kingdom
  • 1994 BMW K1100LT SE, 2006 BMW R1200S, 2006 KTM 400EXC
Owner of a K1100LT, R1200S, and a KTM 400EXC. My car is a Subaru Outback 3.0Rn!

Offline K75RT Keith

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You can test the HES for failure with a heat gun  remove the cover and aim the heat at the HES. let it heat up see if it will start and continue to run.  If it doesn't, the wires on the sensors have fried.

from IBMWR site:

By Don Eilenberger
June 2001
Things I would look at (in IMHO increasing order of probability):

Coils - look at them in the dark with the bike idling, just to make sure there isn't a crack in the towers that is causing arc-over. Doubtful due to the 2nd clue, but easy and cheap to do.
Ignition wires - worth checking the resistance on them. This would be the first place I'd look if we ONLY had clue #1, but #2 can't be accounted for with this. The wires should be 5k Ohms end to end - +/- 500 ohms (they are typically much closer).
Poor seating of the FI computer connector. More than one intermittent K bike problem like this has been fixed by reseating the connector on the FI computer. Easy to do, and no cost at all.
Ignition switch or kill switch partial failure. Some people have had problems with deposits on the ignition switch causing intermittent running problems, cleaning it is the cure. This is in the K bike FAQ.
Starter deposits - given that the bike probably gets quite a bit of use - there have been instances of intermittent problems caused by carbon deposits in the starter motor (BMW does some odd things with electrical paths - that include the starter when it isn't running :-). There is a FAQ on the website on removing and cleaning it. Cost is nil, not really hard to get out once you go at it.
Hall Effect sensor - this is where I think the problem is. It sounds like the intermittent failure of a Hall-effect sensor. Have seen and heard of this before here on the list (Jeff Dunkle - would you care to chime in??).
The test for this (Jeff's test) is done with a heat gun (or a really good hair-dryer). The hall-effect sensor assembly lives behind the T shaped cover on the right (facing forwards - starboard :-) side of the engine. The cover is easily removed with allen wrenches.

The test - let the engine idle - and direct the heat gun at the Hall-effect sensor. If it cuts out when it gets good and warm - this is a big clue. Then turn the heat gun to just blowing air and cool it, try restarting. If it restarts, this is the 2nd clue. You may want to do this test a number of times to make certain it's the fault.

This - to me - is the most likely cause - given the symptoms you describe. The hesitation at higher RPMS indicates a weak spark to me, caused by a partially failed HES. The complete cutout indicates complete ignition failure - again, pointing (when combined with the hesitation) to the HES.

This - unfortunately is the most expensive thing to fix, so it's worth going through the other ones first in the hopes that it will be a cheap fix. 
You can't help someone who doesn't want to hear the answer.

1990 K75RT

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