BMW R1200RT/R1250RT Forum

Hello from the UK.....
I have a no start situation with my 2012 R1200RT 51800 miles.. I recently stripped it down to re-paint the engine, removing the whole wiring loom in the process. I have now refitted the wiring loom, however it wont start. It will crank, but not fire up. I also don't get the pump priming at key on (although it has primed a couple of times randomly, but still no start).
I thought it might be the Fuel Pressure Controller as that can be problematic, so I replaced it with one from my friends bike who also has an R1200RT. Still no start. Swapped the fuel pump, no luck.I put 12volts direct to the pump, the pump works but again, no start.
I have spark, and excellent compression (220-230psi).
I connected my voltmeter to the Fuel Pressure Controller plug, positive probe to the Blue/Green wire and negative probe to the brown. No voltage at key on, but when cranking, I get between 9.4 volts and 10.3 volts.
I've checked the plugs to the ECU, all secure. I have checked continuity between the ECU and Fuel Pressure Controller, (3 wires) all good. Sidestand (propstand) switch checked and all good.
Motorscan showed an error code of 27B8 which appears to relate to the fuel pump, but I've ruled that out.
My next thought is to check the wiring for continuity.
Can anyone suggest a solution..... is there any other component that could affect the no start situation ??
Could the mechanical fuel pressure regulator (no electrical input/output) have an effect?

Thanks in advance

Pull a spark plug and check for spark during start attempt. If you're getting a good spark then pull another plug and check for fuel.

I have checked for a spark on the two outer plugs and all good. I haven’t checked the lower plugs yet. Also the injectors are firing as I checked them with Motoscan. What I don’t know is whether the injectors are pumping enough fuel into the cylinders. Could the fuel regulator not be supplying enough fuel to the injectors ?

If you attempt a start and the engine doesn't fire there will be fuel in the cylinder. Pull a plug and check. If you can't detect fuel in the cylinder and you've already determined the injectors are firing, then the problem is upstream. Could be a clogged filter or line.

Just because I've done stupid things like this myself, I'll ask if you made sure there's fuel in the tank. Also, how old is the fuel?

The first thing I would be doing is checking all connections and your work

because like above I've done stupid things too and its turned out to be the wrong plug in the wrong sensor or one not plugged in

Mark S. wrote: Fri Jan 02, 2026 12:30 pm If you attempt a start and the engine doesn't fire there will be fuel in the cylinder. Pull a plug and check. If you can't detect fuel in the cylinder and you've already determined the injectors are firing, then the problem is upstream. Could be a clogged filter or line.

Just because I've done stupid things like this myself, I'll ask if you made sure there's fuel in the tank. Also, how old is the fuel?

Fuel is fresh. I put five litres in last week

Have you confirmed that fuel is getting into the cylinders?

I ran an injector test using Motoscan and fuel sprayed out of the injectors, but whether it was the right amount, I have no idea. Tomorrow I plan on removing the injectors and cranking the engine and see if they are operating. You can hear the injectors clicking when using Motoscan. It would be handy to know how much fuel the injectors pass in a given time

Update……Today I carried out continuity checks on the wiring from the ECU to all the sensors, etc. Everything was fine except for pin 6 which is the permanent positive live from the battery to the ECU. Pin 3 is the earth, that is fine. Although not a direct short, I had a resistance reading of 43K ohms. This would suggest a very minor short circuit, I would have expected an open circuit. Thoughts please

Problem solved.
Turns out the Cylinder Head Temperature Sensor on the right cylinder head had failed so the ECU blocked the fuel system as it couldn't get an engine temp signal.

Thanks for the update. That was a thorny one!