Hello All, As a last ditch attempt to rectify the above issue before I entrust the work to a specialist, I thought I might try you guys for some advice. In July last year I bought the above bike and despite being a very clean 8k miles machine, it wasn't running right, but everything checked out, so I wasnt unduly worried. Being capable with tools, I downloaded an electronic version of the workshop manual and got to work replacing the fuel filter, spark plugs and then adjusting the TPS, balancing the TBs and tweaking the air bypass screws. I also check the timing just for peace of mind, which was fine. After all the above, the bike seemed to run absolutely fine and idle perfectly when warm, but just refused to idle very well from cold and would often stall if left with out artificially raising the rpm until I set off on a ride. I also noted that the temperature gauge was leaping around intermittently and discovered that the sender was faulty (using the test procedure in the manual). Since the bike has an ECU fed temperature sender, I thought that that might be the culprit for the poor cold idling, so I decided to replace all three senders: temp gauge, rad fan switch and ECU sender - I decided that if one had failed, chances are the others might have as well. Unfortunately having replaced the sensors (with new items I might add) this appears not to have resolved the issue. What's more, the 'fast idle' button on the throttle twist grip appears to have no influence at all, especially when you are supposed to have at least 1mm of 'slack movement' on the throttle twist grip, it just seems to take up the slack when you press the button. I've checked to make sure the actual button assembly is all intact and nothing seems out of the ordinary. My last resort is to get the valve clearances checked, but since it only has 8k miles, I thought clearances might still be good. Being my first Ducati, I've a lot to learn about the nuances of the Bologna twin as I've always had Japanese. Anyway, any help is much appreciated. Thanks, Karl
Hi Karl, I always believe in keeping stuff simple so I would sort the fast idle before looking elsewhere. My 916 has always worked fine with the fast idle from cold but will stall without it. At least you found it!! I've talked to quite a few 748/916 owners who had no idea it was there!!! Hope it proves to be this simple
All the fast idle does is tweak the throttle open a touch, if there is too much slack in the cable it doesn't work, so you could try taking some slack out and it will give more effect. That might be it, but if you still suspect sensors, the temp sensor to the ecu relies on the earth being through the screwed connection, so you could try rigging a secondary earth from the sensor body to the frame as a trial. Next thing would be to ask a ducati mechanic with a mathesis tester to hook it up and run a sensor check. That will check all your sensors out and tell whether the wiring is intact too. You can spend a long time troubleshooting sensor faults and this method is much quicker
Thanks guys. I'll check the cable adjustment again and see if that helps, but I will also check the earthing. Having changed all the temp sensors for brand new ones, and seeing as it has the ECU sensor, I thought the fast idle might be fairly superfluous as the ECU would compensate for cold starts and richen things automatically.
Like I posted, I have to use the fast idle from cold or it will splutter and stall but with it it's been a perfect starter, never an issue! If the ECU does 'richen things' through the info from sensors then mine is duff!!! I believe other fuel injection bikes never have fast idle switches and rely on the ECU which is why I think some owners I've met think their bikes are crap from cold cos they haven't found the said switch I guess! I'm sure others on here with greater knowledge than me will clarify
It might be worth doing a search for similar symptoms/threads primarily as there are so many possible solutions. To start with, have you got std exhaust/ECU chip? also have you acted on the ECU trimmer yet? Has it ever run/idled ok during your ownership? As far as the fast idle adjustment goes - I commend you for doing the slack adjustment by the book but sounds like you need to slowly remove even more slack despite it appearing as though you already have (and correctly). You will be able to feel and see if the arm on the throttle body is returning fully to it's stop. At least this will help marginally while you address your main problem.
Thanks again for your responses. Well I've been out to the garage and again and played around with the fast idle. It occurred to me that my assessment of the fast idle button and cable slack had only been made based purely on what I could see with the engine not running. Sounds stupid I know, as you'd have thought I would have investigated with the engine running. However I fiddled around with the setup until I had what look like roughly 1mm of rotation at the twist grip, but pressing the fast idle button had an obvious visual effect on the TBs. What do you know, it seemed to work! I started the bike and it was really struggling to idle, proving that there was no tension on the cable. I then pressed the fast idle and boom, straight up to 1800rpm! It's amazing how little movement there can be on the throttle, to produce a significant change in engine rpm! When the temp gauge started rising and rpm rose to 2k, I backed off the fast idle and it was fine, a steady-ish idle of 1000 - 1100 rpm, no sign of stalling and a crisp Rev off the bottom with no stuttering or bogging! Happy days! Dutchy916 - it appears it is indeed all in the fast idle switch my friend! Chris - I have for my sins messed with the ECU trimmer and I will be getting the bike on a gas analyser to check the gases and get it set properly. It does have a JHP chip and the obligatory Termigs and one of my first calls was to JHP to check that the chip wasn't some super duper race chip. I will check it all again properly when I get a good chance to run it but at the risk of waking the entire road at 10pm, it'll have to wait. Thanks again for the help.