not having much joy here.I have fitted later type coils top and front,made up a new connector for the front very close to the loom,but not tried to take the whole battery cover to pieces yet.I wanted to test what i have done so far but i cannot get it to start.charged up the battery (new) and there is barely a click,wondering if the immobiliser has been tripped along the way?is there something i need to know,like does the system re set itself? just want to see if this is a fix and if not dreading taking all that wiring to bits.
actually looks like the battery is knackered now,brand new two months ago.wont take a charge of more than 12.8,so just a faint click.bugger...
oh dear,then something else has happened along the way..i wonder what it could be? i did get behind the battery and retreated in confusion,Chris on this Forum has been very helpful,so i will try again and see if i can find the earth strap for the ECU and see how that all looks.I imagine something else has come undone along the way if she is not even turning over now.
Oddly enough, the ecu earths to itself. The battery box is a pita. It helps a lot to use an led head torch and to replace the self tappers holding the heat shield with something a screwdriver can actually grip. I got some with similar thread size but larger heads from Halfords and it made a world of difference. How long will it hold 12.8 for??
Battery problem sorted-Bad earth to the rear cylinder,that was popping out of its collar at the battery end. Got the ECU bolts off and cleaned up the black earth wire to the ECU,checked anything i could see for signs of breakage. Bike fires up again- on one pot still. I checked the front plug,it is new and also completely dry and clean,no smell of fuel,also no smell of fuel when the bike runs. I popped the plug into the coil holder and pushed it up against the top cylinder body to check for a spark.I can not see a spark. Firibng up again and running for a minute or two it stuttered onto two cycliners for maybe 30 seconds. the yellow warning light went off too.Then back to form on one pot. So....WTF??? do you think this might be fuel starvation or simply no spark? (not certain my spark test is correctly carried out?) I am slowly losing the will to live now. Can it be a faulty ECU? surely this really intermittent chipping in on two cylinders is unusual,either on or off you would think?
The coil drivers in these ECUs are known to fail but usually when a semiconductor fails it fails permanently. However it could be some sort of dry joint in the ECU that is making a connection when it is cold but once the bike starts the current through it heats it up a bit and it stops connecting. Another ECU to try would be the best way to find out if that's where the fault lies. Maybe @chrisw could help with that.
Look on the bright side. The more you can eliminate, the more you can narrow the problem down. ECUs are suspect on these bikes and it's the coil drivers that tend to go wrong. I had to replace an ecu and the advice was to replace it with the later 1098 style ecu which can be flashed with a map for your bike. Firstly though, try swapping the coils and plugs to see if the problem follows or remains on the same cylinder. If you have a warning light, you should have a fault code showing, do you know what it is?? The hand book will tell you how to call up the fault code and googling Ducati 749 fault codes will give you a list of what they mean. If it runs on one , that means you have fuel. Apparently, if a coil is not firing, the ecu switches off that injector.
Ah yes, he's replaced both coils. ECU is looking more and more likely. It's a right game working out how to disconnect the ECU multi-plugs when you've not done it before...
all comments appreciated Old Rider. Now i am wondering about another trick which seems to be to run an earth froim the central wire of the diagnostic plug to the battery earth? seems to be a way to sideline a fried internal ECU earth,any thoughts? and is the diganostic plug the little bungeed one on the front wheel end of the battery box?
I think you'll find that's irrelevant. The clue that this has happened is a constantly running fan and it doesn't stop the bike working as far as I know At this stage, @chrisw is your man...
as you can see there is a whole bunch of stuff earthing to the negative battery lead,not sure how many issues this bike has had previously although she has only done 10k miles. if this is the diagnostic plug then it only has 2 wires and three holes,normal?
thanks Derek.Is it an idea to try running an earth to the battery neutral from this? this is the thread i was reading and these guys seem pretty happy with it. https://www.ducati.ms/threads/07-999s-jump-ground-to-ecu-diagnostic-and.128244/
Their reason for connecting the diagnostic ground to battery earth is that they had fitted a diagnostic connector with the power lead connections the wrong way round. This blows an internal earth line in the ECU resulting in the fans running all the time. Earthing the diagnostic ground line restores the ECU sensor ground restoring normal operation. This is not your problem and connecting the black/violet to ground won't make the slightest difference.
