My 1098 road bike appears to have developed a bit of an unusual fault. The front spark plug won’t spark. I have swapped the coils and plugs around and they are fine, so I'm left thinking it’s something more sinister. I see from the circuit diagram one of the troublesome relays feeds the coils, fuel pump and injectors. The fuel pump is priming and the injectors are injecting. Is possible that the relay, if failing would only part function? I haven’t had time to try a swap out yet? Other than loose wires back and forth to the ecu, any other ideas? I did did try an ecu swap – no change. Cheers
The relay supplies power to the fuel pump, the injector and the coils. I think the fuel pump as the biggest current draw would be the first to show problems if the relay was faulty. More likely to be continuity between the coil and the ECU or between the relay and the horiz coil.
Thanks Derek, I have checked the voltage between pin 2 and 1 on the coil connector when the start button is pushed and all looks good there, 11v+. Looking at the circuit diagram the grey and green wire goes back to the ecu 'motor side' pin 10, which I believe is the the red plug. Couple of questions; Can the plug top be easily removed? How can I tell which is pin 10 from the pic below? Any auto sparks near Swindon? I'm a bit rubbish with electrics
That is the motor connector. Looking at the picture top right is pin 38 and bottom left is pin 1. Pin 10 is top left - vertical coil Pin 38 top right - horizontal coil Do some continuity tests. A metal paper clip makes a good probe for the ECU connector.
Thanks Chris, thought I'd seen them somewhere! Continuity is good for both coils. Tried it again on my spare ecu and the coil sparked, I swapped back to the original then no spark. Swapped back again to the previously working ecu then no spark. I can only assume there's a bad connection down there!
If they're resistor plugs, they can do irregular things when they start to fail. Have you tried a new plug?
Could a failing CPS cause these problems? Just think if outputs look ok, maybe there's something amiss with the signal(s) in? Did someone @Derek post an alternative up once? Punto?
When you say continuity is good for both coils, exactly what do you mean by that? From what you describe, logic would suggest the problem lies between the ecu and the front coil. Is it perhaps possible to rig a separate wire between the two to eliminate the possibility of a broken or corroded wire or corroded connector?
I doubt if a duff CPS would cause only one coil to stop firing. It doesn't differentiate between the cylinders, the ECU does by noting a missing pulse from the CPS that indicates that the position and stroke that the crank is on. No harm in trying another though.
Yes, you'll need to remove the textile insulating tape ( I haven't seen stuff like that since the sixties). If you hinge the locking clip back you'll see that at a certain position the hinges can be popped out and the clip removed. Then the top part of the connector has some locking tabs that need pressing and the top part of the connector can be slide off. When you finally put it back together again use self-amalgamating tape instead of the cloth stuff. it will do a far better job at keeping the wet out. I see chrisw has given you the pinout details.
Chris and Derek are the experts. I just thought that if what you said is not entirely clear to me, it may not be to them either. If you had said continuity to both coils is good, then that would be different. Also, it seems possible to me that something like a broken wire may provide enough contact to show continuity but not enough to fire the coil, so if you could rig a separate wire between ecu and coil and the plug then sparks, you will have narrowed down your fault.
I'll still post up my method and readings later. Best not to assume I have any idea at all what I'm doing! Appreciate the input!
