Hello all. Only me! I've been having another dig around. Some things of note. 1. I've had every connector apart, cleaned, and refitted. Found one pin that had been pushed in....turns out that was the signal from the oil pressure switch so that's now working again! (Small victory) 2. I found a bit of loom that had been cut apart (pictured) in the past. Some questionable work, but the grey/green looked intact. Does make me think that it could be a look issue somewhere. Sadly still not working tacho (neither of them are giving me even the slightest hint). Just out of interested. I'm aware that the ECU gets it's RPM signal from the sensor by the water pump, it then goes into the ECU, and a separate signal is then sent to the tacho. Is it even remotely possible that the bike can run correctly with the wrong signal from the sensor? I'm guessing not but you guys have a much better understanding than me! Cheers again
No chance. The ECU uses the crank sensor to determine the spark and injector timing. The presence of a signal from the crank sensor also tells the ECU to turn on the injection relay which provides power to the coils, injectors and fuel pump. Of course it also uses this signal to send the signal to the tacho. It's looking more likely that the fault lies with your ECU. Can you get hold of another to try, although that might not be easy due to immobiliser issues. Or could your tacho be tried on another bike?
I completely agree. I think it's the only way to go now as I am chasing my tail and I've checked and cleaned every connector I can find. I need to check both my Tachos on a Bike with a 16M ECU. Once I know beyond any doubt that they work, I need to test another known working 16M ECU on my bike If it works it's the ECU, if it doesn't it's the Loom. As a side task, the oscilloscope is an option to check my ECU output.
Do all the cheap ones work inside the range required for the Ducati tacho? At that price I will get one and then come back with 101 questions!
Only 1MHz bandwidth on the scope. Not the most useful of tools. You can get a small stand alone scope with 10MHz for just over £20. They also have a signal generator which it's ideal for testing a tacho. Mini Handheld Digital 2 IN 1 Oscilloscope Portable 48MS/s 10MHz Bandwidth Electronic Repair Tool https://a.aliexpress.com/_EHEmVgc
I have check every individual section of the loom, and the loom as a whole. I have continuity from the ECU connector to the connector that plugs into the tacho, and I also have a variable signal (measured using the frequency setting on my multimeter). I also have continuity from the black wire that goes into the back of the tacho, to the battery negative - therefore the earth is confirmed as ok. What I don't know is whether the variable signal the tacho is receiving is accurate (or if the output from the ECU is correct), so I am currently researching oscilloscopes
Yep. All done. - The tacho is getting a signal (just cant confirm its the correct one) - The tacho has a good earth - I have bought a second tacho and that doesn't work either (Although i could be very unlucky and have 2 non working tachos) - All voltages are within spec, so its likely the regulator rectifier is fine
Yes, I have been following the recommendations of fellow very helpful forum members. So far everything tested has been in spec
Ive not tested any resistance as quite honestly i have no idea what i am looking at! This is very much education on the job! Happy to have another area to look into. Are you happy to suggest exactly what i am looking for?
Ok, battery off. Set multimeter to ohms and check that the wire has " continuity" therefore no breaks or a short to earth. Test from one terminal to another, ie pin 24 on ECU to tacho input, then test from terminals to earth just incase you have a short to earth that proves that circuit is good or not. Haynes manual reasonably good.
I note the signal generator on this oscilloscope has an amplitude of 0-3v - is this sufficient to be able to test the tacho? Many thanks. Results as follows: Pin 12 to Green/Grey on tacho connector: Beeps and is at 0.1ohms Pin 12 to connector at right of seat: Beeps 0.1ohms Pin 12 to 19 pin connector: Beeps, 0.1ohms Pin 12 to connector behind headlight: Beeps, 0.1ohms Grey/green connector at tacho to earth: No beep Pin 12 to earth: No beep Black wire on tacho connector to battery negative terminal: Beeps, 0.1ohms All completed with battery disconnected
I apologize , some wiring diagrams are different. Try pin 12 to tacho ohm setting. Or you have dead short from pin 24.
