K1100 bad starting, won't take throttle

[koendd]

So I have this K1100lt in my workshop and I can't seem to get the thing to start ok when cold.
I allready did quit some work on it
(some electrical gremlins to start with).

what I've done:

new plugs (old ones really black)
new filters and seals on the injectors
synchronisation
CO adjustment (1.7% now )
new fuel lines (cracked)
new fuel filter (old 2014)
new fuel pump (just as a test)
measured and tested the Co potmeter (goes from zero to 1040 Ohm, so that should be ok)
temp sensor from coolant has high resistance cold, drops when I manually heat it with a small torch.
Set the TPS with the coolant light method

symptoms:

When it's cold (let it sit overnight), it's hard to start, won't start with the "choke" on. When it starts, it cuts out, does that about 3 times, then it keeps running. you really have to "work" the throtlle to get it to rev properly. backfires through the Throttle bodies when cold.
When you can rev it cold, it dumps a cloud of black smoke.

once it warms up, all is good, starts perfect, runs great (did a testride and goes perfectly well).

any other things I should check? I'd like to get it over with 

[Laitch]

In which year was the K1100LT manufactured?

[koendd]

In which year was the K1100LT manufactured?

04/1995

[rbm]

Remove and carefully check the Z-tube connections the air accumulator to the crankcase.  Could be cracked and it's not in your list of replaced items.

[The Mighty Gryphon]

Remove and carefully check the Z-tube connections the air accumulator to the crankcase.  Could be cracked and it's not in your list of replaced items.

+1 also, check the rubber caps on the throttle body barbs where the vacuum is measured. 

Did you check the vacuum hose to the fuel pressure regulator for cracks?  An easy check is to pull it off the barb on the #4 throttle body and cover the barb with your finger.  If the idle is smoother with your finger over the end, the hose is leaking.

Have you checked the resistance of the engine temperature sensor?  It should be about 2500 ohms when the engine is cold and about 250 ohms when at operating temperature.

There could also be air leaks around the throttle bodies and the rubber bushings above and below them.

[frankenduck]

Have you checked the resistance of the engine temperature sensor?  It should be about 2500 ohms when the engine is cold and about 250 ohms when at operating temperature.

It's a K1100. It uses a different temp sensor than the 2V Ks.



Max BMW lists 12611341602 as an OIL TEMPERATURE SENSOR.  It may be for other bikes where it is used but on K1100s it measures the temperature of the coolant exiting the cylinder head.