I am looking for a working ECU for my 1983 K 100.
Must be off a bike that was running. 
Anyone have one they want to sell?

Thanks Greg C

I do have one but before you buy are you absolutely sure that the ECU is the problem because they have proven over the years to be exceptionally reliable.

RicK G wrote:I do have one but before you buy are you absolutely sure that the ECU is the problem because they have proven over the years to be exceptionally reliable.

My bike is in at a BMW Specialist - they suspect the ECU - they are trying to get an ECU off another bike to try to confirm. My bike (just purchased) has been idle in storage for 10 years. they suspect the solder in the motherboard has deteriorated.
I am just looking to see what may be available if this is the case.

I don't think they should need an ECU to confirm. The info is here to test the inputs and outputs. Have they told you which outputs the ECU isn't providing? What are the symptoms?

daveyson wrote:I don't think they should need an ECU to confirm. The info is here to test the inputs and outputs. Have they told you which outputs the ECU isn't providing? What are the symptoms?

Hi,
Since I have had the bike I have done the following:

1. Drained Fuel flushed system.
2. Drained oil replace filter etc.
3. Flushed radiator/Coolant 
4. Replaced fuel pump hoses filter etc (fuel pump fuse instantly blew when i touched starter - old fuel pump ceased)
5. Freed injectors - all open on a 9 volt battery test.
6. Checked cleaned connections hall, terminals, earths etc. Fuel relay/ECU - checked all fuses
7. Replaced spark plugs - checked spark - strong

I have no pulse on the injectors on cranking. fuel pump runs plenty of pressure (I had not properly tightened clamp and sent a jet of fuel across the garage) 
Spark plugs are dry.
Pulled fuel rail - cranked - no fuel.
At this point I took it to a specialist - as beyond my layman limits (i'm only used to carburetted Aprilia's...this in itself is enough to drive a man to drink) 

Greg C

Check the temperature sensor if it is faulty it can either be super rich because it thinks it's cold or no fuel because it thinks it's super hot as above 111°C. Have a look around the portal pages to find about the tests for the temp sensor.
If the sensor has a very low reading the super hot option is what happens and which is what you would be looking for if it is faulty and giving a high reading (high ohms then it thinks cold and makes it rich). If the plug is not connecting then confusion is the name and it delivers no fuel.

Ditto. 

If the ECU is getting all required inputs but not providing the required outputs, you need another one, I'm punting it's not getting all inputs. 

It seems to me you've got mechanical skills. I'm thinking with your skills and the help of this forum, you can get your brick going, and keep it going. Instead of being driven to drink cause it's beyond you, you'll be having a happy hour beer O clock, cause you diagnosed it and you fixed it. Soon you'll be familiar with it and you'll start thinking, actually this is easier than the Carby days cause there's less moving parts so less to go wrong.

Might seam DAFT but have you disconnected fuel pipe at feed end OF RAIL and cranked with pipe in a container to prove flow from tank to rail, OR disconnect pipe from tank fill pipe with fuel RECONECT now crank see if it fires.You have AIR and SPARK, Just need FUEL.

"I have no pulse on the injectors on cranking"

What do you mean by this? No fuel, no earth, constant earth, no power, something else?

daveyson wrote:"I have no pulse on the injectors on cranking"

What do you mean by this? No fuel, no earth, constant earth, no power, something else?

Injectors are not opening to deliver fuel - so therefore no electricity getting to them. The injectors open when off the bike ding a 9 volt battery test in the tool bench.

OK so probably it's not getting power or it's not getting a pulsing earth which is easy to test with a computer safe test light.

It only gets earth from the FICU, if it's not getting power, the computer is not the problem.

Greg C wrote:Injectors are not opening to deliver fuel - . . .

Here's a little something from a manual containing the operating principles of the Brick's particular LE Jetronic system.


If all explanations of what has been happening are accurate, this tells me the fuel injection relay, the Ignition Control Unit, the Fuel Injection Control Unit and all wiring connecting them need to be examined and tested. It does not tell me to run out and buy one of each unit and replace all the wiring before testing everything; however, it does clarify the interaction of the ignition control unit with the fuel injection relay and the fuel injection control unit.

A break causing a weak connection of a wire in the extreme bend of the wire bundle connected to the Fuel Injection Control Unit plug was the culprit of a failure-to-stay-running problem in one owner's Brick, so anything goes here—faulty FICU, faulty ICU, faulty FI relay, faulty wires, oxidized relay terminals or, perhaps, just a "Well, lookee there; that's all it is!".