Hi All... Apologies for my second post being a technical question. I am trying to diagnose a problem with my 2005 Multistrada 1000ds., and would appreciate any help. The bike starts easily, and idles fine. However... After riding it gently to warm it up, the ignition cuts in and out under load. It feels the same as turning the kill switch on and off for a couple of seconds. If I ease off the throttle, and ride very (very) gently... all is fine.... but as soon as I try and accelerate or maintain anything over 50mph (or so), the ignition cuts in and out again. The clocks and lights stay working, but there is no spark on either cylinder. I have run the bike with a strobe connected, and this seems to confirm a complete loss of spark when under load. The bike will run and rev perfectly well when on my driveway, and seems fine until it warms up. It only happens under load. I am thinking that the ECU is at fault, but maybe something else is causing the ECU to temporarily 'trip'? Any thoughts? ☺
Are you sure that the spark is cutting out? If there is a burst fuel line inside the tank the fuel pressure will be very low, allowing the engine to start and idle but will cut out under load or any circumstance that needs a lot of fuel. It may well be able to accelerate very gently until it reaches a speed where the engine is asking for more fuel than the reduced pressure can supply. Worth checking? If the internal fuel lines are ok then perhaps the pump isn't working properly. Whatever, the cause of the fault is more likely to be an external component or sensor than the ECU itself.
yip, i dont think ECU's are affected by engine load. i doubt rpm sensors are either. under load almost always means the HT circuit. what kind of ignition system is on yours, ie, coil per cylinder, wasted spark system. ect.
Thanks for your reply ☺ My initial thought was fuel, and I have ordered a pressure gauge to test the system. However... I took the bike out with a strobe attached, and it stopped flashing as the engine cut in and out. I tested both cylinders. I guess it is possible that a fueling fault is causing the ignition to cut? ...although I can't see an obvious reason, having studied the wiring diagram.
Yes, the strobe would verify the absence of sparks. Like @finm says, crank sensors shouldn't be affected by load although a faulty one can be affected by revs and/or temperature. So it may be coils breaking down but I can't see both being faulty simultaneously.
as yer man said, recent plug change? i have seen when the wrong plugs cause CAN systems to switch off on a brand of car that seems to share a lot of ignition components with ducati. you never know, and never say never.
I bought the bike from a guy, knowing that it had a fault. He said that he tried replacing the fuel pump assembly, then gave up on it ...as it was driving him nuts. I don't know if he changed the plugs. He said that the bike was running well, until the problem started. I am happy to invest in an ECU repair, if that is the problem, but first need to rule out other potential causes.
i guess plugs (dont mix and match, thats the fiat issue) main earths and power supply to the ECU would be a good place to start.
Thanks to everyone that has replied, I appreciate it ☺ So... Is it possible that a faulty plug, or coil, could be causing the ECU to trip and intermittently cut the supply to both coils?
never say never. if its the ECU i think it might be, they are prone to coil drivers in the ECU to fail, tho i have never seen two go down at the same time. i use a company called BBA Reman for testing, i dont know if the do bike ECU's. might be worth a call.
I will test ride the bike with a meter attached to the ECU supply, to rule out a loom related problem. Then I will test the fuel pressure, once my new gauge is delivered ☺ (Although I don't think the ECU reads fuel delivery, the earth for the pump relay seems to be supplied by the ECU). ...so it could be no spark and no fuel? I noticed that when the coils kick back in, there is no backfiring/popping.
The ECU supplies an earth to the fuel pump relay coil at switch on and while the engine is turning. This energises the relay which in turn supplies power to the fuel pump, injectors and coils. If the relay drops out so does the fuel and sparks.
The first thing I tried was replacing the fuel pump relay, although it wouldn't hurt to run the bike with the relay metered ☺ ...give me a set of carbs any day! My old aircooled Monster is so simple, in comparison
