906 paso no spark. bring on the revolution

discussions specific to the 906 Paso
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dmartis
Posts: 14
Joined: Sat May 07, 2011 7:30 am
model: 906 Paso
year: 1990
Location: New Zealand

906 paso no spark. bring on the revolution

Post by dmartis »

the never ending continuing saga ha. my 906 has no spark at the plugs. i have 12v + at the coils and i have 12v + going into the digiplex... i have tried a 2nd hand replacement crank angle sensor (cond unknown). i have new replacement coils to try (california cycleworks p/n 2vcoils) but these will reguire some mounting brackets etc to be made up before i can fit them), have tried the one feeding the rear cylinder loosely. my model has leads that can be removed so i have tried new plugs and leads. WHATS NEXT ???. Am i correct in thinking that the problem may be the digiplex. also has any one fitted these coils and are any other mods needed to fit them. i must nearly be through my apprenticeship ha ha. party on guys
Mc tool
paso grand pooh-bah
Posts: 1875
Joined: Wed Dec 05, 2007 12:35 am
model: 906 Paso
year: 1990
Location: Newzealand

Re: 906 paso no spark. bring on the revolution

Post by Mc tool »

Do you still have 12v at the coils and the digiplex while the starter is cranking ? . Make sure the digiplex is properly earthed . Where in NZ are you ?
I wish I was young again............Id be heaps smarter than last time
dmartis
Posts: 14
Joined: Sat May 07, 2011 7:30 am
model: 906 Paso
year: 1990
Location: New Zealand

Re: 906 paso no spark. bring on the revolution

Post by dmartis »

yes i do still have 12v while cranking. i presume im measuring it correctly at the digiplex ie i have the plug out and my multi meter into the 6th socket from the left (red). i am 1 hour north of auckland in wellsford nz. at this stage i am only testing the coil supplying the vertical cylinder but there is no spark at either plug. thank you ;-)
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paso750
paso grand pooh-bah
Posts: 5558
Joined: Sun Jul 18, 2004 12:00 am
model: 750 Paso
year: 1987
Location: southern Germany

Re: 906 paso no spark. bring on the revolution

Post by paso750 »

... and my multi meter into the 6th socket from the left
that only measures the 12V at the Marelli unit. The coils get a ground signal from the ECU while the constant 12V come from the main wiring.
As Hamish suggested check if the ground connection of the ECU on pin 10 is ok.
Replacing parts with used ones in unknown condition is a gamble.

Is this a sudden problem or has anything been done to the bike after the last time it was still properly working ?
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jrwizbang
Posts: 10
Joined: Sun Feb 16, 2014 3:53 pm
model: 906 Paso
year: 1990
Location: Wolfeboro, NH,

Re: 906 paso no spark. bring on the revolution

Post by jrwizbang »

I agree with the "check the ground" crowd. during my winter long paso rescue project the number one issue I had was bad ground wires and loose connectors.
dmartis
Posts: 14
Joined: Sat May 07, 2011 7:30 am
model: 906 Paso
year: 1990
Location: New Zealand

Re: 906 paso no spark. bring on the revolution

Post by dmartis »

thanks guys, the ground seems ok i guess. i put my meter in pin 10 and 6, had 12.8v at rest and 11v while cranking. is it possible it is the pick up still and how can i test it. i purchased second hand from a ducati spares who said it was from a running bike but i have my doubts. the bike has been in the shed for a year plus. it all started when it was running fine then after a very short ride would drop down to one cylinder it seemed and jerk its way back to base. once cooled it would start again until finally it would not start. the earth at the regulator was loose and i have now secured it but it seemed to make no difference. hmmm really appreciate all your suggestions. party on
nickta
Posts: 295
Joined: Tue Jul 24, 2012 8:54 am
model: 907 I.E.
year: 1992
Location: Cairns, Queensland, Australia

Re: 906 paso no spark. bring on the revolution

Post by nickta »

dmartis wrote:thanks guys, the ground seems ok i guess. i put my meter in pin 10 and 6, had 12.8v at rest and 11v while cranking. is it possible it is the pick up still and how can i test it.
To test the pick up, measure the resistance of it. It should be around 720 ohm, or there abouts. They are just a coil of copper wire, so either go open circuit, or short circuit. Usually where the wires disappear into it. I'm not a 906 owner, so have no idea how the digiplex gets an earth. I would guess through the body of the digiplex, through the mount and to the frame. If there is corrosion, or a bit of crap between the digiplex and the chassis, then the earth wont be very good. Again, measure it with the multimeter set on ohms. The difference between your sitting voltage and cranking voltage looks a wee bit high, though not unheard of. If its a bad earth, the higher the current (ie: starting) the more of a voltage drop there will be across that bad earth, which means less volts elsewhere.

Cheers.

Nick.
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paso750
paso grand pooh-bah
Posts: 5558
Joined: Sun Jul 18, 2004 12:00 am
model: 750 Paso
year: 1987
Location: southern Germany

Re: 906 paso no spark. bring on the revolution

Post by paso750 »

You didn`t confirm if you have the 12V directly at the coils. Do you ?
If so set the multimeter to ohms and see if you measure a short between pin 9 of the ECU and the connector of the horizontal coil (pink wire) then do the same with pin 11 and the vertical coil (yellow/grey wire) just to be sure the connections between the ECU and the coils are ok.
Then make sure the ground connection from the battery to the frame and engine is clean and tight.

The vacuum hose only controls the advance so if that wasn`t ok you still would have spark. The only other thing I could think of which impacts the ignition is the gap between the pick-up and flywheel. It would have to be too wide to send no signal to the ECU but this isn`t something that changes over time so it`s unlikely to be the issue. Just be sure that on your new used pick up the washer of between it and engine case has the same thickness as the old one.

If the wiring is ok I'd be leaning towards the pick-up or the ECU as chances are lower that both coils, both ignition wires or both sparkplugs go bad at the same time.
lane1feathers
Posts: 258
Joined: Thu Sep 20, 2012 11:48 am
model: 906 Paso
year: 1989
Location: Perth, West. Australia

Re: 906 paso no spark. bring on the revolution

Post by lane1feathers »

Do you have a relay installed for the coils? If so it may be old, cheap, faulty, etc and not switching properly. Also the earth to it may need cleaning. Check out my thread 'The story so far' about ground wires from relays.
Also (and this may seem like a silly question to most on here, but let's cover all bases) are you resting the plug against the head while testing for a spark? If not you won't get one while testing but may infact be getting good spark while riding and the fault may be something else like rust in the tank clogging your filter reducing fuel flow which will make it sputter and fart back to base.
Lane
89 Dark Blue 906 Paso
Ducati Paso, It's an 'understanding'....
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