Author Topic: Help k100 working badly cutting off,and spelling fuel from exhaust.  (Read 9875 times)

Offline ripikapardopo

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hi there. i'm from portugal and i have a bmw k100 scrambler. i've having some issues with it.
it start to working badly, like it was only 3 cylinders. i have to push trottle otherwise bike dies, and it start to spell fuel from the exhaust, i mean a lot off fuel. sometimes she works well.
any ideia of what this could be? i don't know what to do anymore.
cumps
  • Lisbon - Portugal
  • bmw k100 '86

Online Martin

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Re: Help k100 working badly cutting off,and spelling fuel from exhaust.
« Reply #1 on: February 17, 2016, 03:31:46 PM »
Have you had a look at the spark plugs, are they all wet or just one. If it is just one, earth that spark plug to the cylinder head and check to see if it has a good spark. Get someone to crank it over while you check the spark plug. If they are all wet also check to see what the spark is like. It could be possible that you could also have a faulty temperature sensor switch or a bad connection. If the bike refuses to start due to flooding, you can remove the fuel pump fuse labelled Kraftstoppe, which is number six counting down from the top. Try to start the bike and as it starts wait until it starts to die and put back the fuse. It helps if you have someone to work the throttle. Do this and post the result.
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline Laitch

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Re: Help k100 working badly cutting off,and spelling fuel from exhaust.
« Reply #2 on: February 17, 2016, 03:38:17 PM »
Welcome!

Did you work on the bike before this happened? What have you done to figure this out? Do you have a manual for your bike?

The last time symptoms like these were discussed here, the problem was the ECU box and its plug had gotten wet.
http://www.motobrick.com/index.php/topic,7677.msg54012.html#msg54012
Once the system was dried and the plug was tightly connected, the problem was gone. Have you checked to be sure your ECU plug is tightly connected?
  • Along the Ridley in Vermont.
  • 1995 K75 83,000 miles
I wept because I had no radials until I met a man who had no splines.
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Offline ripikapardopo

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Re: Help k100 working badly cutting off,and spelling fuel from exhaust.
« Reply #3 on: February 22, 2016, 12:38:46 PM »
ok. i'm desperate right now. all the plugs r wet, i replaced them and i clean the  temp sensor that stays behind the trotle bodies, the 2 that stays under the engine (under radiator)
the ecu plug (out some electric spray on all plugs). problem remains.
a few months i had to put a new fuel pump on it.
i've noted now that when i turn key i dont hear de fuel pump woks for a second or two like before, only when i push cluch and hit starter button. i don't know if this could be a problem.
it keeps spitting lots of fuel out from the ehxaust and white smoke when i hit start. Sometimes she starts but working really bad and then die and then its leaking lots of fuel from the 4 to 1 part of exhaust.
i don't know what to do anymore and in portugal its difficult to find someone that really understand how the k bikes works.
hope to see this problem solved
  • Lisbon - Portugal
  • bmw k100 '86

Offline TimTyler

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Re: Help k100 working badly cutting off,and spelling fuel from exhaust.
« Reply #4 on: February 22, 2016, 12:42:39 PM »
Exactly which fuel pump did you use to replace your old fuel pump?

If all plugs are wet it usually means you are not getting spark.

Offline ripikapardopo

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Re: Help k100 working badly cutting off,and spelling fuel from exhaust.
« Reply #5 on: February 22, 2016, 12:47:31 PM »
https://www.motobins.co.uk/bmw-parts.php?model=K%20Series&bikeref=K100
the one that costs 131 ex vat but the bike did about 6000km already
  • Lisbon - Portugal
  • bmw k100 '86

Offline ripikapardopo

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Re: Help k100 working badly cutting off,and spelling fuel from exhaust.
« Reply #6 on: February 22, 2016, 12:48:42 PM »
about the plugs, i test them on the cylinder and they all did spark
  • Lisbon - Portugal
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Offline TimTyler

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Re: Help k100 working badly cutting off,and spelling fuel from exhaust.
« Reply #7 on: February 22, 2016, 12:52:31 PM »
I wonder if a failed fuel pressure regulator would cause this.

Offline ripikapardopo

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Re: Help k100 working badly cutting off,and spelling fuel from exhaust.
« Reply #8 on: February 22, 2016, 12:56:20 PM »
ok, i.ve check the hoses to it but i dont know how to test it..
  • Lisbon - Portugal
  • bmw k100 '86

Offline TimTyler

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Re: Help k100 working badly cutting off,and spelling fuel from exhaust.
« Reply #9 on: February 22, 2016, 01:00:29 PM »
Can you smell or see fuel in the vacuum hose that connects to the rear throttle body?

There's no "test port" on a K bike but you could insert a meter into the hose that feeds the injector bar.


Offline Laitch

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Re: Help k100 working badly cutting off,and spelling fuel from exhaust.
« Reply #10 on: February 22, 2016, 01:03:01 PM »
about the plugs, i test them on the cylinder and they all did spark
After you're finished checking the fuel pressure regulator, if that isn't the problem check to be sure the plug wires are connected from the correct coil terminal to the correct cylinder spark plug.
Read the first four posts here.
  • Along the Ridley in Vermont.
  • 1995 K75 83,000 miles
I wept because I had no radials until I met a man who had no splines.
https://tinyurl.com/RillRider

Offline ripikapardopo

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Re: Help k100 working badly cutting off,and spelling fuel from exhaust.
« Reply #11 on: February 22, 2016, 01:08:33 PM »
alright thank you guys. tomorrow i'll check the fpr and the spark plugs wires and then i post the results. something that is making me some confusion is the fuel pump  that dont work that few seconds before i hit start button to.
  • Lisbon - Portugal
  • bmw k100 '86

Offline ripikapardopo

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Re: Help k100 working badly cutting off,and spelling fuel from exhaust.
« Reply #12 on: February 22, 2016, 01:30:06 PM »
can u tell me what is the correct position to the plug wires?. just to be sure. i think that the longest one is connected to the front one, then the 2 one and 3one, the 4 one( near the coils) is longer than the 2one. is this right?
  • Lisbon - Portugal
  • bmw k100 '86

Offline TimTyler

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Re: Help k100 working badly cutting off,and spelling fuel from exhaust.
« Reply #13 on: February 22, 2016, 01:33:22 PM »
From: http://www.k100-forum.com/t3914-solvedhelp-with-new-to-me-85-k100-starter-running-while-battery-is-hooked-up

Quote
Both cables for the first (no 1) and last cylinder (no 4) connect to the forward coil, the two for the middle cylinders (2 and 3 counted from the forward end) on the aft coil. Position on the coil is not relevant.


Online Martin

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Re: Help k100 working badly cutting off,and spelling fuel from exhaust.
« Reply #14 on: February 22, 2016, 01:34:55 PM »
If it is a fault with the temp sensor cleaning the connection won't fix the problem. You need to test it with a multimeter. Test as per attached chart courtesy of RBM under COOLANT TEMP SENSOR VALUES. Have you tried pulling number 6 fuse and starting it?
 Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline ripikapardopo

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Re: Help k100 working badly cutting off,and spelling fuel from exhaust.
« Reply #15 on: February 22, 2016, 03:03:53 PM »
thanks timtyler, i'll check first in the morning if they're ok.
Martin i did what u told me to. bike starts when i turn off the fuse but work badly, like it was working only with 3 cylinders and when i put the fuse again she floods making a big pool on the floor. the sensor u mentioned is the one that is right under de radiator behind the fuel rail or the ones under the engine?
still no noise from fuel pump when turn key and i don't have healight to i don't know if this is relevant.
  • Lisbon - Portugal
  • bmw k100 '86

Online Martin

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Re: Help k100 working badly cutting off,and spelling fuel from exhaust.
« Reply #16 on: February 22, 2016, 04:20:44 PM »
Rip see posting on Dec 03 2015 EXCESS FUELLING WON"T START for location of switch you can find this in Search. It is ard to get to. You can either remove the air box or the radiator. I think air box is easier If the readings are fine at least you have eliminated something. Read the whole topic.
Regards Martin.
  • North Lakes Queensland Australia
  • 1992 K75s Hybrid, Lefaux, Vespa V twin.

Offline tsnap

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Re: Help k100 working badly cutting off,and spelling fuel from exhaust.
« Reply #17 on: February 23, 2016, 08:45:58 PM »
Please be extremely careful and have a large smothering blanket nearby and a fire extinguisher very close when working on this type problem!  A blanket like a moving company uses will smother a fire, while oil soaked coveralls will make a bigger fire.

Also, there is always a possibility that the exhaust pipes on the lower side are flooded with gasoline and clogging the exhaust pathway, so your observations  of the engine performance  :hehehemay be clouded by that condition.  when the pipes finally go boom, you will have no bike to worry about.

Just a word of caution, from bad experiences.

tom :musicboohoo: :hehehe
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Offline K1300S

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Re: Help k100 working badly cutting off,and spelling fuel from exhaust.
« Reply #18 on: February 23, 2016, 09:19:39 PM »
have you pulled the injectors?  this sounds like one or more injectors are stuck open.  there is no other way for that much fuel to end up in the exhaust.
Project Thread "K75s Midlife Refresh"
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Offline tsnap

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Re: Help k100 working badly cutting off,and spelling fuel from exhaust.
« Reply #19 on: February 23, 2016, 10:22:35 PM »
great observation.

tom
  • Kirksville, MO
  • K1k1100 Radar Sloth1994 48K ABSII no shame wall 4 me
just plain tom, he is a dirt mean man

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