1150 GS won’t start

[Mullgs]

Year 2000, 62000 miles. Got the bike MOTD yesterday, passed easy. Went to visit my daughter, bike running a bit rough, before and after fuelling up. This morning I drained some fuel from the fuel lines, just at the jubilee clips, to see if there was any sign of water/muck. Looks ok, tried to start but won’t go. Turns over, fuel pump primes, but won’t fire. Anybody got any ideas, I’ve only got the tools in the kit, next step is recovery TIA.
Update, dash lights all work, pulled plugs (dry?) and held against frame, no visible spark. Why would I lose spark and fuel overnight?

 

[NeilDD]

Make sure you have not dislodged the throttle cable on RHS

 

[Mullgs]

Make sure you have not dislodged the throttle cable on RHS

Yeah, it’s fine.

 

[Dickyb]

I had similar problems. Turned out to be a blocked filter and split hose in the fuel tank. Are you getting a decent spray of fuel out of the injectors?

 

[theoneandonly]

you did put the side stand up ?
don't laugh , i've had mine 10 years and still forget sometimes.

 

[Mullgs]

you did put the side stand up ?
don't laugh , i've had mine 10 years and still forget sometimes.

Yeah, stand up, clutch in.

 

[Ian J Hartley]

The fact that your bike was running rough before might indicate a Hall sensor failure. Given that you can’t get a spark, and the plugs are dry indicates injectors and Coil not working. Both are controlled by the Hall sensor.

The fact that your fuel pump primes, and the engine cranks, looks on the surface that all the power to the various components is present, just that there is no signal from the hall sensor to get them to work.

Try this.
bike on main stand
side stand up
Remove both plugs, leave connected to HT and grounded
put bike in high gear.
ignition on
turn the back wheel.
as you turn the wheel, you should hear the fuel pump prime. If it doesn’t then the hall sensor is not signalling the motronic that the engine is turning. You should also see a spark though sometimes it’s difficult to see.

 

[Mullgs]

I had similar problems. Turned out to be a blocked filter and split hose in the fuel tank. Are you getting a decent spray of fuel out of the injectors?

How do I check?

 

[Ian J Hartley]

How do I check?

leaving the electrical connector and fuel line still attached to the injector. Undo the two screws securing the injector to the throttle body and gently ease the injector out of the throttle body and move it to one side. Preferably stick the injector into a suitable container to catch the fuel. As you crank the engine, provided you have fuel flow and pressure, and the injector opens, you should see a fine spray pattern of fuel.

 

[Mullgs]

The fact that your bike was running rough before might indicate a Hall sensor failure. Given that you can’t get a spark, and the plugs are dry indicates injectors and Coil not working. Both are controlled by the Hall sensor.

The fact that your fuel pump primes, and the engine cranks, looks on the surface that all the power to the various components is present, just that there is no signal from the hall sensor to get them to work.

Try this.
bike on main stand
side stand up
Remove both plugs, leave connected to HT and grounded
put bike in high gear.
ignition on
turn the back wheel.
as you turn the wheel, you should hear the fuel pump prime. If it doesn’t then the hall sensor is not signalling the motronic that the engine is turning. You should also see a spark though sometimes it’s difficult to see.

Only managed to turn the wheel slowly, but no noise from pump. Kinda looking like the Hall sensor, if I can find a diagnostic will that confirm it on this model?

 

[Ian J Hartley]

A diagnostic tool similar to the GS911 would tell you whether the Hall sensor signal was missing. The check needs to be done with the engine cranking, as that’s the only time the sensor gives out a signal.

There are a few voltage checks you can make, such as checking for +12v at the HT coil (pin 2 Green wire) with ignition on this should be there constantly. Also removing the injector electrical connector and checking pin 1 (green/white wire) for +12 volts, which is only there momentarily for the brief period that the fuel pump primes. If they are all OK, then there’s only the Hall sensor to consider.

Sometimes when the hall sensor starts to fail, the Tachometer starts behaving erratically, which is another indicator.

 

[Pekkavee]

Only managed to turn the wheel slowly, but no noise from pump. Kinda looking like the Hall sensor, if I can find a diagnostic will that confirm it on this model?

The pump should start shortly once in every full turn of the engine.

 

[Steptoe]

The pump should start shortly once in every full turn of the engine.

Also if the pump primes as you rotate the engine that doesn’t mean the hall sensor is working perfectly ok, it can still be the cause of non running - but if the pump doesn’t prime then 100% , in the cases I’ve diagnosed, it has failed.

 

[DrFarkoff]

Only managed to turn the wheel slowly, but no noise from pump. Kinda looking like the Hall sensor, if I can find a diagnostic will that confirm it on this model?

Did you check the pump connection is home correctly and also at the bike side of the loom to make sure it is actually getting power and ground

And if you have a power probe you can also simply a positive to the pump loom feed and supply a ground

Makes sure the basics are all working before you dive in

 

[Ian J Hartley]

Did you check the pump connection is home correctly and also at the bike side of the loom to make sure it is actually getting power and ground

And if you have a power probe you can also simply a positive to the pump loom feed and supply a ground

Makes sure the basics are all working before you dive in

Come on Doc, Please reread the OP’s first post. Particularly the bit about “Fuel pump primes”.

 

[Mullgs]

Update:
Bike recovered to garage and diagnostic showed two faults on Hall sensor, confirming general opinion. Part ordered, to be fitted next week. Many thanks for all the helpful info guys, this is the best bike site by miles, not one smart arse comment. Cheers, Alex.

 

[theoneandonly]

hall sensor always shows 2 faults 'til the engine is spinning.

in my experience.

 

[Mullgs]

hall sensor always shows 2 faults 'til the engine is spinning.

in my experience.

Established no spark.