No spark - both cylinders

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pseudonoise

No spark - both cylinders

Post by pseudonoise »

My 93 907 has no spark from either coil (nothing to the coils) and I was wondering if anyone had any suggestions as to what may have caused this. I suspect the computer only because of the events that lead up to the lack of spark. Here's what happened:

1) The bike just bogged and died on me one day. Pulled over to the side of the road, check the ignition switch and the kill switch (it was a very sudden bog). Everything was on so I fired it back up, went about a 200 feet and then the same thing happened. This time it wouldn't start back up.
2) I checked for spark and it was there.
3) The fuel pump would not pressurize every time I turned the ignition on so, being that it's the original pump with 20,000mi, I figured it needed replacement.
4) The pump was replaced with an alternative from OEM as described in this forum (http://forums.ducatipaso.org/viewtopic. ... w=previous). The pump now pressurizes and appears to be working up to that point.
5) I now have no spark in both cylinders.

I thought there may be a reset button on the the computer but after looking around in the "box" I can't see anything that resembles one. The manual I have doesn't even mention a reset button. I know some FI bikes have an ignition or pump cutoff when the bike goes upside down (possibly simulated by me removing the old pump) but again, can't find anything that would detect this.

I asked the local Ducati shop if they could reset or bench test the computer for me but they don't even have a shop manual for the 907 (no kidding, that's what they told me).

Any suggestions would be appreciated. If I can't fix this thing soon I'll have to truck it over to the other side of the state to get it looked at.
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du907
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model: 907 I.E.
year: 1992
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Re: No spark - both cylinders

Post by du907 »

I'll be thinking on this; and once the problem has a little time here on the board you'll start getting some ideas.
In the mean time, download the wiring schematic from this site and start looking around. Seems to me if you are getting no electricity to the coils, then it would not be the ECU. Electrical things are like what you described. It works and suddenly quits. Possibly a relay has gotten weak, like maybe the three on the heat sink beside the head light. Check fuses, and the main fuse strip on the left side under the seat. I would check the two amp connectors on the left side just under the tank that are tied to the frame. If one of those has worked loose or disintegrated from the heat that will cut the engine. Check the main plug into the ECU that it has not worked loose. Check Battery, ground connection, connectors from the alternator, the wiring harness altogether for melted wires due to heat build-up because of corrosion.
We'll keep working on it.
du907
Last edited by du907 on Sat Oct 10, 2009 12:44 am, edited 1 time in total.
Tamburinifan
paso grand pooh-bah
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model: 907 I.E.
year: 1991
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Re: No spark - both cylinders

Post by Tamburinifan »

Just guessing a little:
2) I checked for spark and it was there.
So you had spark after the first stop. So hopefully no ECU problem.

Then you did some work....

First,
is the battery fully charged?
Have you tried a fresh pair of plugs?
That both coils stopped working at the same time is unlikely.

Second,
could the work done after the first stop caused something?

I`ve learned,
it it often were you`ve last fiddled w something the problemo is... :evil: :thumbup: :lol:

Just my 2c.
Last edited by Tamburinifan on Sat Oct 10, 2009 12:49 am, edited 3 times in total.
Gert

907 I.E. -91
M900 -97
MTS 1100s -07
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du907
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Re: No spark - both cylinders

Post by du907 »

By the way. The shop manual is available on this site.
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Laddie907
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Re: No spark - both cylinders

Post by Laddie907 »

the fuel pump and the ignition / ECU are totally independant (except that they run off the same battery) - if the initial "bogging" was due to the fuel pump it didn't cause the spark to go away.

there is a possibility that the testing for spark has burned out the ignitors.
these are located on the LHS of the bike up near the regulator. Why I say this is that the ignitors build up a charge pulse (like a capacitor) and this is discharged to the coil for the spark, the ECU controls the discharge timing. If when you tested for spark the spark didn't earth the charge can burn the ignitor.

check you have power to the ignitors.
if you are lucky the loss of power for spark could be the fuses or relay

one last dumb thing to check: the kill switch...yes.
cranks but no spark....
I have had one bike half to pieces only to find the kill switch was the cause...
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higgy
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Re: No spark - both cylinders

Post by higgy »

I have had one bike half to pieces only to find the kill switch was the cause...
Been there done that :shock:
always check the simple things first,power,ground,voltage drop, OH and ,er make sure there is fuel in the tank, :,(
Ducati,making mechanics out of riders since 1946
There's no problem so bad that a little fixing can't make it worse! : )
If it ain't broke keep fixin it till it is
88 750
90 906
92 907ie
pseudonoise

Re: No spark - both cylinders

Post by pseudonoise »

Thanks for the quick responses.
I was doing a lot of cranking during the troubleshooting so maybe I did burn out a relay/wire/connection. I'll download the manual and start tracing everything. Other than that the battery is fully charged, plugs are good (I tried a couple), and all the fuses are good. I also ohmed out the crank sensor and it was within spec (according to other posts I read).
It may be a little while before I get back into the garage to start this project back up but I will reply with any findings.
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persempre907
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Re: No spark - both cylinders

Post by persempre907 »

good luck with the manual... I doubt you will find there some answer to your questions.
CIAO!
Francesco
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Bomber
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Re: No spark - both cylinders

Post by Bomber »

Had a very similar problem, bike would crank, no spark etc.
Even when the bike was warm and had been running fine, suddenly just cranking but would not start.
My fault was caused by one of the 2 injector relays,the ones with fuses !
A previous owner or mechanic had replaced a fuse in the relay, but it was a loose fit.
This made the operation of the relay intermittent, but when the bike was running the vibration was enough to keep the relay working.
I changed both relays and never had another problem.
The relays are still available from Ducati and are not too expensive.

Hope this helps

Gerry
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Laddie907
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Re: No spark - both cylinders

Post by Laddie907 »

Bomber's post about relays remineded me of something...

the wiring to the relays (spade connectors) are not positively retained.
I found that plugging the relay into the block can cause the spade connector to be pushed down if the male and female connectors aren't correctly aligned...

this can cause an intermittant connection...and can be hard to trace.
I had to poke the spade connectors back up on to the relay spades from underneath.

I also had a think about the fuel pump...
the pump won't run if the line pressure is retained at 3 bar...so I'd be inclined to have the old pump checked before you throw it away.
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