BMW K bikes (Bricks)


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brickrider

brickrider
Life time member
Life time member
I've read with interest all the postings I could find related to the mysterious throttle position switch (TPS). I foolishly moved the one on my bike in the course of renewing the fuel hoses and other rubber bits. Now its all back together and I find the overall running is worse that when I began the work Crying or Very sad
I've done all I can to refine the set-up of the bike, following the description in the Haynes workshop manual and various posts here. I now have concluded the TPS was not functioning when I bought the bike last autumn, because it accelerated and slowed without a trace of lurching. Having adjusted the unit, the bike now is not nearly as smooth running. Okay, so much for preamble. My question is this: to render the TPS non-operational, can I just loosen the set-screws and slide it down to its extreme (lower) range of adjustment or must I physically remove the plug-in cable?
In spite of all the posts on this subject, I continue to be unsure of its role in engine management. If it cuts fuel to the injectors at closed throttle, why does the engine continue to idle at all? I've read that there are actually two switch modes. The first "click" should be heard as the TB plates just begin to open, and another "click" at WOT to increase fuel to the injectors. I was able to adjust the unit so it clicks when the TBs first open, but I do not hear a click when the TBs are completely open. Would this indicate the TPS is defective?
Thanks for your advice and insights.

    

charlie99

charlie99
VIP
VIP
brickrider .....have a look on the portal page for the efi trouble shooting link

in there is the description and photo of the operation and parts .

the low end switch is actually a microswitch and presents a positive click ...whilst the wof position is open contacts with out the spring assisted action .

i have mine positioned so that the idle end is no longer effective ...personally ...like some others ...i find the operation of it not working suits me just fine ........i prefer the even backoff ...even if it is using some more fuel in the process ....rather than the definate fuel cut operation ...

in the setup that i have used (just rotating the switch setup a bit further out of range ) the wof function is still effective so all the equipment is in place and nothing to disconnect but no cuttoff is noticed


__________________________________________________
cheezy grin whilst riding, kinda bloke ....oh the joy !!!! ...... ( brick aviator )

'86 K100 RT..#0090401 ..."Gerty" ( Gertrude Von Clickandshift ) --------O%O
'86 k100 rs.. #######..  "Fred " (f(rame) red ) ( Fredrick leichtundschnell ) - -
bits and pieces from many kind friends across the k100 world ...with many thanks ..
1987 k100rs ########   "Red"  - (red sports rs TWB style )
1989 K100rt #009637   "Black Betty"  (naked rt ala Nigel , now sporting an rs main fairing )
    

ReneZ

ReneZ
Life time member
Life time member
Don't forget it has two functions - one with closed throttle and one with fully opened throttle.


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Greetings from Florida Australia! Having a 'new' K     Surprised-o: 

Rene


BMW K100 - 1985 (0030029) Scotland 1985 K100RS throttle position switch Rain
BMW K1200GT - 2003 (ZK01223) Florida
BMW K1200GT - 2004 (ZK27240) Australia
    

Rick G

Rick G
admin
admin
Sorry a double up because my net connection is to say the least crap



Last edited by Rick G on Wed Mar 28 2012, 07:07; edited 1 time in total


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1999 K1100 LT with a Big Block 1200
    

Rick G

Rick G
admin
admin
Probably best to adjust it with a meter connected.
With the throttle at rest turn the TPS clockwise looking at it from the rear of the bike to be sure the contact is made (the meter should go to full range and 0 ohms. then turn it counter clockwise till the meter reading goes to the rest stop this means the switch is open and non functional at the no throttle situation but will give the wide open throttle signal to the computer slightly earlier but that is OK. Itis very important for the computer to get that signal because otherwise the engine can possibly run lean and that can be absolutely disasterous.
There are three wires going to the TPS one is a common the others are closed and wide open a little bit of fiddling will tell you which one is which.


__________________________________________________
"Man sacrifices his health in order to make money.
Then he sacrifices money to recuperate his health.
And then he is so anxious about the future that he does not enjoy the present; the result being that he does not live in the present or the future; he lives as if he is never going to die, and then dies having never really lived."   Dalai Lama


Bikes 1999 K1100 LT with a Big Block 1200
    

brickrider

brickrider
Life time member
Life time member
Thanks. I hadn't thought about the danger of lean running a high speeds. I definitely want to avoid that. I'll see if I can put the multimeter to good use. That's always an adventure as electrickery and I are not always on good terms. Laughing

    

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