This electrical problem has me stumped..

[Steptoe]

R1100S - twin spark model. 39k miles.

No spark at the plugs, no pulse at the injector plug and no power to the fuel pump.

Plug in my gs911, flashes up -battery current 3.5 volts and no communication with controller.

Battery has 12 volts. Engine turns over nice and fast . All fuses OK

I can physically switch the fuel pump relay and get the pump going. Swapped fuel pump relay and motronic relay with spares i have ( more than one for each).

Plugged in my hall sensor tester and getting signals from both sensors.

Swapped the motronic unit over with my twin spark loan bike.

Nothing doing...... bike had an alarm on it, now removed and in the bin. Did all the above tests with alarm fitted, and done them all again after removing alarm. No difference.

Curious why the gs911 is refusing to read/connect. Hence why i swapped over motronics...

Side stand switch all works as it should. Down and in gear engine doesn't turn over, up and clutch in and it does etc etc...

Done my head in today...

 

[Uncle-Fester]

How are you testing for voltage at the battery to get 12v?

Could it be a bad earth connection somewhere in the ignition circuit?

I'm no mech/elec so feel free to shoot me down, but I've had earth faults cause all sorts of weird stuff over the years.

 

[Black Rooster]

kill switch fault or faulty sidestand switch ?


sorry never seen the bit about u tested the side stand switch



tis bad news when steppers asks for help

 

[Fanum]

Kill it.
Kill it dead.
Then burn it.

'Tis the work of the devil I say

 

[fatnfast]

Does the 911 plug into the r1100 diagnostics plug, Im guessing yes? If its flashing up battery voltage 3.5 volts then Im assuming its taking this reading from diagnostics plug pin 6 (red/yellow wire) which takes its feed from F4.
F4 also feeds the motronic relay, fuel pump relay and the actual motronic unit as you know.
I think my first port of call would be a voltage check at F4 to confirm 12 volts, then checking the feed motronic relay pin 30, fuel pump relay pin 30, motronic unit pin 23 and the diagnostics plug. After that, IF you find the voltage has dropped considerably at any of these end points I would use the split half technique to narrow it down.

Hopefully it will be a simple break in the feed/corrosion (I think the F4 feed has a common junction point similar to the common earth junction thats causes problems on the GS).

 

[nick.ct]

Does the 911 plug into the r1100 diagnostics plug, Im guessing yes? If its flashing up battery voltage 3.5 volts then Im assuming its taking this reading from diagnostics plug pin 6 (red/yellow wire) which takes its feed from F4.
F4 also feeds the motronic relay, fuel pump relay and the actual motronic unit as you know.
I think my first port of call would be a voltage check at F4 to confirm 12 volts, then checking the feed motronic relay pin 30, fuel pump relay pin 30, motronic unit pin 23 and the diagnostics plug. After that, IF you find the voltage has dropped considerably at any of these end points I would use the split half technique to narrow it down.

Hopefully it will be a simple break in the feed/corrosion (I think the F4 feed has a common junction point similar to the common earth junction thats causes problems on the GS).

Top answer, logically presented..................................... hope you're right

 

[Uncle-Fester]

Does the 911 plug into the r1100 diagnostics plug, Im guessing yes? If its flashing up battery voltage 3.5 volts then Im assuming its taking this reading from diagnostics plug pin 6 (red/yellow wire) which takes its feed from F4.
F4 also feeds the motronic relay, fuel pump relay and the actual motronic unit as you know.
I think my first port of call would be a voltage check at F4 to confirm 12 volts, then checking the feed motronic relay pin 30, fuel pump relay pin 30, motronic unit pin 23 and the diagnostics plug. After that, IF you find the voltage has dropped considerably at any of these end points I would use the split half technique to narrow it down.

Hopefully it will be a simple break in the feed/corrosion (I think the F4 feed has a common junction point similar to the common earth junction thats causes problems on the GS).

That was gonna be my next suggestion.......

 

[mspenz]

Does the 911 plug into the r1100 diagnostics plug, Im guessing yes? If its flashing up battery voltage 3.5 volts then Im assuming its taking this reading from diagnostics plug pin 6 (red/yellow wire) which takes its feed from F4.
F4 also feeds the motronic relay, fuel pump relay and the actual motronic unit as you know.
I think my first port of call would be a voltage check at F4 to confirm 12 volts, then checking the feed motronic relay pin 30, fuel pump relay pin 30, motronic unit pin 23 and the diagnostics plug. After that, IF you find the voltage has dropped considerably at any of these end points I would use the split half technique to narrow it down.

Hopefully it will be a simple break in the feed/corrosion (I think the F4 feed has a common junction point similar to the common earth junction thats causes problems on the GS).

Sh1t, wish that my inner cranium functioned with that degree of rational!!

 

[Roger 04 RT]

R1100S - twin spark model. 39k miles.

No spark at the plugs, no pulse at the injector plug and no power to the fuel pump.

Plug in my gs911, flashes up -battery current 3.5 volts and no communication with controller.

Battery has 12 volts. Engine turns over nice and fast . All fuses OK

I can physically switch the fuel pump relay and get the pump going. Swapped fuel pump relay and motronic relay with spares i have ( more than one for each).

Plugged in my hall sensor tester and getting signals from both sensors.

Swapped the motronic unit over with my twin spark loan bike.

Nothing doing...... bike had an alarm on it, now removed and in the bin. Did all the above tests with alarm fitted, and done them all again after removing alarm. No difference.

Curious why the gs911 is refusing to read/connect. Hence why i swapped over motronics...

Side stand switch all works as it should. Down and in gear engine doesn't turn over, up and clutch in and it does etc etc...

Done my head in today...

For the starter relay to pull in, +12v is available on the plus side of the starter, Motronic and fuel pump relay coils, so that's not your problem.

You've checked clutch and side stand so they're okay too.

The fuel pump relay also needs the Motronic working, which needs a good +12v on the unswitched side of the Motronic relay, and then the switched side with the key on and the side stand up or bike in neutral (assuming the neutral SW works).

Since the GS-911 is reading a low voltage, which it measures from the same unswitched side of the Motronic relay, it sounds like +12 is not making it across fuse 5 even though fuse 5 looks good. The wire coming from fuse 5 is red/yellow. I would measure the voltage at fuse 5 (both sides), at the diag connector pin 6, at unswitched side of the Motronic relay, and if need be at pin 23 on the Motronic.

This red/yellow 12v can be out but the starter will turn over fine. I guess if it was me, I'd start by attaching the GS-911 (as a load) and pull the Motronic relay and see if there was 12v on the unswitched (hot) side. It should be there and at the 911.

 

[fatnfast]

Hi Roger,
Is that info good for the twin spark R1100S Steptoe is dealing with? When I had my t/s 1100 I couldnt find a wiring diagram covering the motronic/relay side. My assumptions that its fuse 4 providing all the feeds is only based on my memory, so could be wrong. I was at the time looking at installing an 'imobilisation' switch and the red/yellow wire looked to be a choice place to splice into and stop the bike running.
Thinking logically, as the bike had an alarm system fitted and then removed, it would stand to reason that F4 (F5?) feed would be disturbed somewhere along the line and could well be causing the problem.

 

[Roger 04 RT]

Repost, fixed Fuse 1

For the starter relay to pull in, +12v is available on the plus side of the starter, Motronic and fuel pump relay coils, so that's not your problem.

You've checked clutch and side stand so they're okay too.

The fuel pump relay also needs the Motronic working, which needs a good +12v on the unswitched side of the Motronic relay, and then the switched side with the key on and the side stand up or bike in neutral (assuming the neutral SW works).

Since the GS-911 is reading a low voltage, which it measures from the same unswitched side of the Motronic relay, it sounds like +12 is not making it across fuse 1 even though fuse 1 looks good. The wire coming from fuse 1 is red/yellow. I would measure the voltage at fuse 1 (both sides), at the diag connector pin 6, at unswitched side of the Motronic relay, and if need be at pin 23 on the Motronic.

This red/yellow 12v can be out but the starter will turn over fine. I guess if it was me, I'd start by attaching the GS-911 (as a load) and pull the Motronic relay and see if there was 12v on the unswitched (hot) side. It should be there and at the 911.

Hi Roger,
Is that info good for the twin spark R1100S Steptoe is dealing with? When I had my t/s 1100 I couldnt find a wiring diagram covering the motronic/relay side. My assumptions that its fuse 4 providing all the feeds is only based on my memory, so could be wrong. I was at the time looking at installing an 'imobilisation' switch and the red/yellow wire looked to be a choice place to splice into and stop the bike running.
Thinking logically, as the bike had an alarm system fitted and then removed, it would stand to reason that F4 (F5?) feed would be disturbed somewhere along the line and could well be causing the problem.

First, thank you for picking me up on the error, I was looking at 2004 R1150RT and the fuses are different for the R1100S. I went back to the source document and then changed F5 (the Motronic fuse for RT) to F1 (the Motronic fuse for R1100S) in the repost above.

The removal of alarm could have disturbed something but I don't know that wiring. The GS-911 and Motronic are both fed from Fuse 1 though. So I think I'd start with that circuit. Probably though Steptoe has already checked that but the GS-911 reads voltage directly from the Diag plug on the red/yellow wire between diag pins 6 and 4. Since that's all it uses, either red/yellow is wrong or ground at the diag plug.

 

[wessie]

Like others, I be suspecting a poor earth as it seems the diagnostics connector does not have 12V across the relevant pins.

I've used a jump lead from the battery negative terminal to various parts of the frame/engine to locate earth problems in the past.

 

[Roger 04 RT]

...

Done my head in today...

Did you ever figure this one out?