1998 ST2. Was running over the summer and was last used 2 weeks ago, all fine . Went to get it out today wouldn't start. Lifted the tank, removed the air-filter, liberally sprayed Holts Easy-Start into the throttle bodies, cranked it over - nothing. Pump primes so as it wouldn't start with the highly volatile Easy-Start, I'm beginning to suspect there's no spark. Several hours later (well it seems that way) the body work is off and I can get at things. Pull the plugs and definitely no spark at either. Try new plugs, same thing, no spark. I can hear the relays clicking when the ignition is turned on so I'm working my way through the workshop manual at present and googling away but if anyone has any suggestions please let me know. TIA.
One helpful symptom appears (?) to be no spark on either cylinder, so favourites, those which will only affect both cylinders, for a kick-off could be:- 1/ Ignition relay (front, left of forks?) 2/ Timing sensor and/or connector Others will be along soon. Never owned one (got an engine though!) - will engine still churn if sidestand switch or safety cut-out switch are playing up? I guess you've done a lot of wiggling already..
Never assume a relay is working just because it "clicks", if the contacts inside are pitted up they may not pass a current. Quite rare but it can happen, put a meter on the outputs and check for current on and off to verify its operation.
@Chris @Hughdg thanks. Are the ignition relays the pair of identical ones under the seat? Rather than the 2 that are on the LHS of the forks (see photo of those). The pair of relays are sealed so I can't test the input or output of them as I can't get to bare wires. I've tried to test if there's 12v at the plugs that feed the coils but unfortunately the probes on my multimeter are too big to fit inside the teeny weeny little holes of the connector, I've got to find some micro-probes or jerry rig something with some strands of old speaker wire .
So what are the pair of big black ones under the seat next to the ecu? They’re about the size of the black one in the photo, I thought they were for the coils. Perhaps I’m going mad
injection relays I believe, one for injectors and coils and one for fuel pump possibly - I think this diagram is correct Paul? and has the luxury of wires being in correct colour (so you can easily verify by checking underseat wires leading to relays).
Usually one for the fan and one for the fuel pump/coils - or they are on my ST4s, I know others may be different. As Chris says above, you can relate it to the wiring diagram above. Try switching their places (if they've both got the same number and arrangement of pins) and see what happens. Of course, if switching them makes the bike start, you'll need to replace the inop one otherwise your fan may not work.
If the fuel pump primes then the ignition relay should be fine, one of the underseat black ones is probably your problem
Re-ignition relay, I think you’re probably right Harry, so we can rule that one out, (sorry Paul, I missed the bit where you said it primed.)
Slightly out of my depth re: ST2/ST4 subtle changes to loom/ancilliaries, but this diagram (a rotated version of one I posted yesterday) is titled:- "late ST2, early ST4" so may not be correct for yours Paul, if you have accompanying handbook you could cross-reference from time to time.
Thanks Chris. That looks like the wiring diagram I have in the workshop manual albeit mines b/w. I’ll do some more circuit testing today.
I'm chiming in on this a bit late. The relays under the LH fairing are the main (ignition) relay, the headlight relay and the flasher relay. The 2 relays under the seat are the fan relay and the fuel pump relay. Apart from the indicator relay they are all identical and it is usual to swap the fan and fuel pump relays to help diagnosis. If the fuel pump is priming at ignition on the relay must be working. Check to see it the fuel pump relay is switching on when the engine is cranking - either listen for the pump or connect a test light to one of the coil positive connectors (brown/white wire on either coil). The lamp will light up if the relay is switching. If not, the ECU isn't switching the relay on, so no signal from the crank sensor which could be a faulty sensor or a poor connection. If no CPS signal then no pump and no sparks. If the CPS is working you should see the tacho needle pulse slightly when cranking. Or, less likely a faulty ECU.
This is really perplexing me know. Got the multimeter across a coil feed, turn on, crank, nothing 0.00v. Hence no spark. Checked fuses again but as the relays click on key on I know the fuses are good. Checked both relays under the seat, both clear of any corrosion. Disconnected the RHS one, turn on, fuel pump primes but doesn’t stop priming. Disconnected the LHS one as well, turn on, nothing, as one would expect. Swap left for right and reconnect both, turn on, pump primes and stops as it should but still nothing at the coils. 0.00v
Your initial state with the pump turning on and remaining on could possibly be a sticking relay. With them swapped the operation appears normal BUT at switch on there should definitely be power to the coils. The relay output goes to the pump, the injectors and the coils - all of which should be powered for a couple of seconds at switch on. If I recall correctly, the relay has two pin 87 contacts. It is possible that one of these goes to the pump and the other to the coils/injectors, although the diagram shows them splitting further into the loom. Check the relay base carefully for corrosion. It is the one with 2 brown/white wires and an orange/wire. Also check for continuity between the brown/white at one of the coils and the brown/white at the base of relay pin 87. See the ST2 ignition/injection wiring below.
If the ignition relay fails there's a lot more doesn't work as well as no sparks. There will be no lights, no horn, no indicators, no brake lights, no dash lights. Virtually a completely dead bike.
Ok just working on no power to coils - it’s before coils not much other than relays or fuse to look at if the power hasn’t got that far ......
@Derek your post #13 above arrived just as I posted my post #14 which I wrote before seeing what you’d written. On reading your post 13, I checked a couple more things. 1. there’s no fuel pump operation when I crank the engine, only for the initial few seconds at key on. 2. there’s not a flicker from the tacho needle when I crank the engine, nothing, nowt, rien, de nada. If I’ve interpreted your post correctly that would indicate a duff CPS. So I pull the CPS connector apart. Connections are all clean and look good. I’m doing some research as to how I can test the CPS and for the benefit of future readers I came across this: https://hooshmand.net/replacing-the-crankshaft-position-sensor-on-a-ducati/ Useful. I remove the CPS completely and proceed to test it, assuming I did it correctly, nothing, no output signal when a magnet is put near the end of it, thus it would seem that’s the cause of the problem. Off to order a new one now, it’ll be a week before it gets here though.
There’s definitely no corrosion on those relays, they’re good. There’s no power at the coil even momentarily at key on but I’m going to triple check that right now. Thanks for your help.
