Be forewarned this is a long & tedious description of an as yet unsolved starting problem with my '06 Breva 1100. I'm letting those know who aren't knowledgable or interested in (electrical) things so I don't waste their time.
Speaking of being knowledgeable, I know enough about electrics of any kind to get myself in trouble and not enough to get myself out.
Here are some introductory facts because I know there are many reasons why a bike won't start and I have ruled out the easy ones. The kill switch isn't pressed; the battery has plenty of charge; the sidestand isn't down. It isn't the infamous "startus interruptus" because I installed the MPH kit years ago to solve that one. (The kit was removed in the testing below to simplify things.) As evidenced by behavior during testing described below, the ignition switch and starter button seem to work fine. I have not recently mucked with the circuitry in any way. When the bike is running I know of no other malfunction.
The symptoms began after I had ridden several hours at NV highway speeds in very hot weather. No idea if that has anything to do with it. I replaced the battery and thought that was it because it started right away. The same no-start happened the next morning. The only other symptom was that near the end of each day the engine stumbled and had trouble maintaining idle.
So, now to my attempts to diagnose, or at least document, the problem. I started at the starter relay (and I'm still there). The photo shows the wires going into the back of the plug attached to the relay. The colors of course don't match those in the wiring diagram I have. The Rosetta Stone for figuring out which was which was discovering that the orange wire with yellow stripe has continuity with the wire connected to the starter motor solenoid. Ta-da! It's the red & green wire in the diagram. So these are my guesses for the connections to the relay on my bike, with corresponding Bosch terminal #s in parentheses:
1 (86) - black w/red stripe
2 (85) - yellow
3 (30) - white & brown
5 (87)- orange w/yellow stripe
By the way, since the light relay (#4 in the diagram) is the same kind as the starter relay, I swapped them at one point and saw the same symptoms. I assume the chances of having two bad relays is low enough I can assume the relay isn't the problem.
When I turn the key on & hit the starter button the relay makes a click sound but nothing happens at the starter motor. About 4 seconds later it makes another click. The delay must be the time programmed into the ECU to try to get the engine started. (The service manual says it's 10 sec.) So far, so good. My confusion began when I read the voltages at the plug. I thought the relay must work just like a simple Bosch relay with its 30-87/86-85 terminals. Evidently not.
With the ignition on, I read 12V at #1 & #3 and zero at #2 & #4. This is as designed according to the ECU circuit diagram on the last page of the service manual. I understand #3 being hot; when the relay is triggered it's the voltage that goes to the starter. But #1?? If it's hot why doesn't that trigger the relay?
And get this: when I press the start button the voltage at #3 drops to ZERO !?!?
I used a short piece of wire to connect #1 & #2 at the back of the plug. When first connected the relay clicks as it does when the start button is pressed. When the wire is removed there's a second click. That's all that happens.
When I connect #3 & #5 the starter motor kicks over as I'd expect.
THEN... when I connect #1 & #2 again, leave the wire in place, and hit the start button, the bike starts and runs normally.
I guess I could make the #1-#2 connection permanent and see what happens but that's surely just covering up a problem which will bite me later.
Any ideas what the problem is at the relay, plug, or elsewhere in the circuit that could cause this?
Thanks,
Ron
Speaking of being knowledgeable, I know enough about electrics of any kind to get myself in trouble and not enough to get myself out.
Here are some introductory facts because I know there are many reasons why a bike won't start and I have ruled out the easy ones. The kill switch isn't pressed; the battery has plenty of charge; the sidestand isn't down. It isn't the infamous "startus interruptus" because I installed the MPH kit years ago to solve that one. (The kit was removed in the testing below to simplify things.) As evidenced by behavior during testing described below, the ignition switch and starter button seem to work fine. I have not recently mucked with the circuitry in any way. When the bike is running I know of no other malfunction.
The symptoms began after I had ridden several hours at NV highway speeds in very hot weather. No idea if that has anything to do with it. I replaced the battery and thought that was it because it started right away. The same no-start happened the next morning. The only other symptom was that near the end of each day the engine stumbled and had trouble maintaining idle.
So, now to my attempts to diagnose, or at least document, the problem. I started at the starter relay (and I'm still there). The photo shows the wires going into the back of the plug attached to the relay. The colors of course don't match those in the wiring diagram I have. The Rosetta Stone for figuring out which was which was discovering that the orange wire with yellow stripe has continuity with the wire connected to the starter motor solenoid. Ta-da! It's the red & green wire in the diagram. So these are my guesses for the connections to the relay on my bike, with corresponding Bosch terminal #s in parentheses:
1 (86) - black w/red stripe
2 (85) - yellow
3 (30) - white & brown
5 (87)- orange w/yellow stripe
By the way, since the light relay (#4 in the diagram) is the same kind as the starter relay, I swapped them at one point and saw the same symptoms. I assume the chances of having two bad relays is low enough I can assume the relay isn't the problem.
When I turn the key on & hit the starter button the relay makes a click sound but nothing happens at the starter motor. About 4 seconds later it makes another click. The delay must be the time programmed into the ECU to try to get the engine started. (The service manual says it's 10 sec.) So far, so good. My confusion began when I read the voltages at the plug. I thought the relay must work just like a simple Bosch relay with its 30-87/86-85 terminals. Evidently not.
With the ignition on, I read 12V at #1 & #3 and zero at #2 & #4. This is as designed according to the ECU circuit diagram on the last page of the service manual. I understand #3 being hot; when the relay is triggered it's the voltage that goes to the starter. But #1?? If it's hot why doesn't that trigger the relay?
And get this: when I press the start button the voltage at #3 drops to ZERO !?!?
I used a short piece of wire to connect #1 & #2 at the back of the plug. When first connected the relay clicks as it does when the start button is pressed. When the wire is removed there's a second click. That's all that happens.
When I connect #3 & #5 the starter motor kicks over as I'd expect.
THEN... when I connect #1 & #2 again, leave the wire in place, and hit the start button, the bike starts and runs normally.
I guess I could make the #1-#2 connection permanent and see what happens but that's surely just covering up a problem which will bite me later.
Any ideas what the problem is at the relay, plug, or elsewhere in the circuit that could cause this?
Thanks,
Ron
