BMW K75 Standard - No Spark on All 3 Cylinders

[Rokah]

Hey all,

Hoping someone can help me confirm my diagnosis or point out anything I might be missing.

My bike: K75 Standard, 170,000km. Has been running absolutely fine with no issues prior to this.

Issue: Bike died on me while riding after 5 mins. I managed to get it to start once briefly after that but it died again immediately and hasn't fired since. It does crank. All lights are on.

What I've Checked So Far:

— Full electrical system is alive: dashboard lights, headlights, instruments all working normally
— Battery is good, bike cranks strongly
— Fuel pump is audible on ignition on
— Removed the injector ramp and cranked — all three injectors are squirting, so the EFI side and Hall Effect Sensors appear to be functioning correctly
— Pulled all three spark plugs and grounded them against the engine while cranking — confirmed zero spark on all three cylinders
— Fitted three new spark plugs and retested — still no spark
— Located and inspected the ICU connector — it is completely clean, no corrosion, no pushed back pins, no broken wires.
— Cleaned all ground connections, both in gearbox and under the tank

My thinking: Since all three cylinders have no spark simultaneously, it can't be the coils or plugs individually. The Hall sensors must be working because the injectors are firing. That leaves the ICU as the most likely culprit — either it has lost power/ground or it has died internally. The next step I haven't done yet is probing the ICU connector pins for voltage with the ignition on. Is this worth doing?


Does my diagnosis make sense or am I missing something obvious?
Is there anything else worth checking before I condemn the ICU?

Any help appreciated. Cheers

[daveson]

We don't know yet if both hall sensors are good. One sends an output through a brown wire, one through an orange wire. Sometimes the wiring colours are different.

The following video tests the brown wire. Repeat the test for the orange wire to confirm if both outputs are good.

https://youtube.com/shorts/P3X0zvDY6Vw?si=yYC_L1ovWnyABBmU

[Laitch]

— Fuel pump is audible on ignition on

Does this description mean that when you turn the ignition to On but do not press the starter button, you can hear the fuel pump?

[Rokah]

Went to test today. Before starting I tried starting the bike. It worked right away....

I'll try the hair drier on the hall effect sensor to see if that makes it fail....

[stokester]

When is the last time you changed your fuel filter?

[Rokah]

Finally got around testing the HES.



I tested up to 90ēC, both seem to work. Should I go higher? Is there anything I should check now that it is off the bike?

Thanks!

When is the last time you changed your fuel filter?

Two years ago