88 k100rs needs help fuel problem

[simpleman]

I have had this k bike for 6 years and i am a year around rider. The bike has roughly 64k on it. just recently it has been stalling out intermittently. Sometimes I can ride for 50 miles other times maybe only five. when it stalls sometimes it will start up instantly other times it wont. The bike will always start the next day. I have checked for spark on the times that it wouldn't run after stalling and it has always had spark. I replaced the fuel pump, fuel pump relay, and the fuel control module. I once road it to work and it sat in the parking lot for 11 hours then it started and ran for 15 seconds and stalled. I took it to the BMW dealer and they charged me 165 us dollars for nothing as they told me they ran it but never was able to get it to stall. Today i checked the voltage at the plug for the fuel pump out side of the tank and it has 11.8 volts at idle 12 plus around 2k rpm while its running and when pressing the starter button. I am looking for some advise. Where should i go from here? Suggestions?

[Laitch]

I'm thinking you should look at this post  http://www.motobrick.com/index.php/topic,7480.0.html  and this thread,  http://www.motobrick.com/index.php/topic,7490.0.html  then this section in general to see if problems there seem similar to yours and have been solved. http://www.motobrick.com/index.php/board,97.0.html

[kenray]

Could be your ignition switch. My k100 rs was acting weird. Replaced the switch and problem went away.  Did you replace the fuel filter? Does't cost much to replace, could'nt hurt. Good luck. kenray in Katy Tx.

[simpleman]

I took my ignition switch apart and found it to be corroded. I cleaned it up. Also took apart the start switch and found it to be in about the same condition. The bike has been idling for about 1.5 hours now in the driveway with a fan on it. Think this may have been the problem.

[Solly]

Next time it does it , check for power and trigger{pulsing ground at the injectors}. But use a logic probe of sorts. If you do not have one ,go to radio shack and buy a red or green L.E.D. and attaché a wire lead to each of the two terminals and VIOLA you now have a computer safe test light or just throw caution to the wind and use a 12 volt test light and risk poppin the injector drive transistor in the ECU. Anyway you should get a pulsing lamp when cranking. If not then the crank sensor is falling out or still the ECU may have a problem with either a input {crank sensor, Power feed, Ground feed, Cam sensor if equipped}. Not as hard as it sounds. If you have spark, and you can hear the pump running{not real accurate}and have correct fuel pressure},then check the injector drive . Good Luck Sol

[Solly]

BTW beemer may call the Crankshaft position sensor a engine rpm sensor or engine speed sensor or hall switch. All are common nomenclature for the same device on german diagrams. And you should have a good wiring diagram.

[Laitch]

It's impressive how much crud these bikes can accumulate and still run, more or less—I hope that was the fix, simpleman. I'd put that 4-pin pump wire connection next on the list for cleanup if it were my bike, given how much flora I see on your ignition switch, but looks like you've got the patience and persistence to get it under control.

[simpleman]

Thanks to everyone who helped me out. I'm out of town for work right now. I won't be back until Wednesday. The ignition switch and starter switch seemed to be the worst. I checked the 4 pin connector and surprisingly it was in good shape. When I left the bike it was running good but I won't know for sure until I get back and put a few hundred miles on it.

[The Mighty Gryphon]

I think you may have fixed it.  I had a similar but not identical problem with my bike last spring.   Cleaning the key switch has cured it for the past 5 months, and my switch didn't look anywhere near as bad as yours.