Before I burn this bike to the ground, I'll post here in hope someone can help me out. I'm just finishing a ground up build on my 996 superbike. I'm having starting issues. The starter motor turns the engine over but I'm not getting any spark from the plugs or fuel through the injectors. Fuel pump primes and switches off with ignition and turns on during cranking (had a open end hose from the tank to a bucket to prove this). I've checked crank position sensor gap (even gapped below Ducati recommended minimum) , replaced crank position sensor with spare I had, tested power to coil plug (gets 12V on one side but ground side isn't getting switched), tested wiring loom, replaced ECU, checked fuses, swapped around under seat relays. The only way I can get the spark plugs to spark and injectors to open is when I rub the crank position sensor hard (day up and down movements with magnet touching the metal) against a piece of metal. Any ideas on what to do next would be greatly appreciated. At this point I'm probably going to buy a new loom and see how that goes.
Was it a new sensor? Or if you can borrow one from a working bike it would eliminate that as being a problem.
You could check the resistance of the wires from pins 11 and 28 to the crank sensor connector. it should be virtually zero ohms for each of them. You should also check that the screen, pin 1 of the connector is connected to ground. If not the signal from the crank sensor could be swamped with electrical noise.
Did you remember the ground wire for the ecu? The bike will turn over and do everything it’s supposed to but won’t get a signal to fire the injectors or spark
Bit of an update. I pulled the plugs out and tried starting with no load on the stater. Success! Injectors and spark plugs both working. But! When I put the plugs back in, charged my lithium ion battery back to 100% and connected a small jump starter to it, I had no spark and injectors weren't opening. It seems strange to me as the engine is cranking really well but doesn't seem to have enough juice to switch the injectors or the plugs I am running pistal 14:1 high compression pistons. Would this have anything to do with it?
Check the onload cranking voltage. Is it not possible that the voltage is dropping too low for the ecu? You could always try bump starting it down a very steep hill.... My race bike always needs a slave battery for cold starts, it will turn over but not fire, when hot it's not so bad
oh, dear, i fought those symptoms (intermittent) for three years before it finally gave up the ghost. which does make it so much easier to diagnose when yer OCD wont allow you take take random guesses. bump start every time, refuse to kick off the button. even tho it span over fine fine i narrowed it down to the starter motor drawing down the voltage at the engine ECU. I had heard of these symptoms back in the day when i worked in a fiat dealership tho had never experienced it until i owned a fugly. which do appear to use the same tech. 8yrs after fitting the a new starter. never once had any issue with it.
Have you checked the voltage drop at the battery when cranking? It will drop momentarily until the engine starts (out on your case doesn’t) but shouldn’t drop below 10.5 volts. If yours does then I’d suggest the battery is fubar and the starter when loaded with trying to crank the engine against compression is drawing all the power.
From Motorcycle Specs ZA (so I take no responsibility for accuracy) but standard CR on a 996 is 11.5:1 or you're running 14:1 and you're wondering why you're having starting issues? Have you ever tried to kick over a big single without a decompression lever?
You can swap out the gear on the starter motor and the transfer wheel for 999 parts, you get a better turn over by reducing load on the starter, also add a direct ground onto the starter to the battery! I have done the 999 starter gear swap and my bike turns over nicely
After further fault finding today thanks to the replies, when starting the voltage drops to 9 ish volts which I'm assuming is way too low for the ECU to be working correctly. I have done the late model starter gear mods, new sprag clutch and gear and upgraded battery cables. I did try a seperate ground cable from the battery to the starter housing, it seemed to improve things (small momentary sparks but not consistent). Out of ideas now except to replace the starter (is there a heavy duty option?) or put even bigger battery cables in to try and help with the volt drop
Junk the HC pistons and all will be well. On a road bike your choice makes absolutely no sense. The 996 may look modern but it's an old engine design originally conceived in 1973 and first built in 1986. It was never designed for such a high compression ratio. If your reason for fitting HC pistons is because you plan to track or race the bike (and enjoy the prospect of regular engine rebuilds) then you would be much better off removing the alternator and starter motor and fitting a total loss ignition system instead, starting the bike using rollers.
Alot of people have run the same HC pistons without issues on a road bike so I doubt that is what is causing me grief
Change the battery for a new one first of all. The fact it drops to 9v on start up indicates it's not holding it's charge. The starter motor is having to overcome the increased compression, is drawing all of the diminished power available from the battery and thus there is non in reserve to power the injectors and coils. Get a good battery with a high CCA rating, make sure it is fully charged for at least 24 hours before attempting to start and then try. Make sure the battery is then subsequently maintained with an optimising charger such as an Optimate 4 or 5. From the symptoms you've described and the things you've done so far, changing the starter motor for a new one will not fix your problem IMO.
i hooked up a v,large car battery to mine to try and eliminate the poor battery question including wiring direct to the starter. nada, zero spark.
does sound like an electrical power drain somewhere, and despite a good starter churn speed, you can't rule starter out as said, or sprag for that matter although latter nearly always accompanied with extra/different noises during churn. I think you mentioned a loom swap, which is drastic but again, a possibility and ditto all ignition-related connectors. As a possibly helpful symptom, did you find any connector corrosion in any loom connectors during rebuild?
