spark, but no start revisited

discussions specific to the 907IE
Post Reply
User avatar
DoubleDuc
Posts: 34
Joined: Mon Jul 28, 2014 2:12 am
model: 907 I.E.
year: 1991
Location: Va, USA

spark, but no start revisited

Post by DoubleDuc »

Thanks for all the previous suggestion regarding no spark issues. Hoping for current issue suggestions:

Bike started, rode for 15 minutes, parked, afterward turned off/on fine.
Next Day: No spark, removed relays, replaced relays, started.
Next Day: Spark but doesn't start ----

What I've tried:

I pulled one (new) plug out, while leaving it attached to the plug I ran the starter. It did not have cyclic spark, but once I released the start button, the plug emitted a 'large' blue spark; however, voltmeter shows continuous 12 volts.

Swapped coils and plug wires from '93, no avail.

Starting fluid in intake, no fire.

Gas in spark plug holes, nothing.

When trying to start, without any test procedures in-place, I do smell gas from the exhaust, not overly flooded. The only thing I can think of is that the timing belt is completely off or if there is something like a distributor causing the spark to not be in cycles, but I was thinking this was the function of the coils. Maybe the injectors, but I would think I would get a fire from gas in the spark plug holes.

I see there is a plug on the EMU, can I interface with this for troubleshooting?

Anything would be appreciated as I don't want to take her to the shop.
User avatar
Derek
paso grand pooh-bah
Posts: 768
Joined: Thu Nov 03, 2011 10:13 am
model: 907 I.E.
year: 1994
Location: Scotland

Re: spark, but no start revisited

Post by Derek »

The fact that the bike is getting fuel and not firing (not even with a starting fluid) suggests that there are no sparks while it is cranking, assuming there is compression. Try plugging another plug into a plug lead, leaving the plug in the engine in place, then cranking the starter and observe for sparks. There should be a repeating spark while the engine turns over.
You say the voltmeter shows a continuous 12V. Where are you measuring it?
After removing and replacing the relay the bike started but didn't the next day. As only the relays were disturbed this suggests the problem is still associated with the relays.
1994 907ie
2017 Supersport 939
2015 Scrambler Classic
1982 Pantah 500SL (now sold)


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

Re: spark, but no start revisited

Post by paso750 »

why open a new topic for the same unsolved problem?

G.
User avatar
higgy
paso grand pooh-bah
Posts: 3327
Joined: Tue Jul 29, 2008 9:50 pm
model: 907 I.E.
year: 1992
Location: Hilltown,Pennsylvania
Contact:

Re: spark, but no start revisited

Post by higgy »

Last edited by higgy on Tue Jun 16, 2015 10:54 am, edited 1 time in total.
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
User avatar
DoubleDuc
Posts: 34
Joined: Mon Jul 28, 2014 2:12 am
model: 907 I.E.
year: 1991
Location: Va, USA

Re: spark, but no start revisited

Post by DoubleDuc »

Thanks for the replies, Derek:
There should be a repeating spark while the engine turns over.
There's not. Tried leaving the plug out, attached to plug wire and starting w/ kill switch in run position.
Outcome w/ two different types of brand new plugs: No cyclic spark, only one spark after releasing the start button (probably why it backfired in earlier attempts to start); one odd thing is the voltmeter reads 6v & 12v depending on the plug. I am measuring the voltage on the spark gap and grounding on the bike; the 6 & 12v are constant (they don't fluctuate).
After removing and replacing the relay the bike started but didn't the next day. As only the relays were disturbed this suggests the problem is still associated with the relays.
I saw there are some new 'compatible' relays in other posts (Bosch and others). But in the available new replacement relays, the prongs have different functions according to the schematics provided on the relays themselves. Anyone familiar with using the different relays; must I do rewiring?

Pooh-Bah, I think you offered some relays from Fiat in a previous post - do you have two that you are willing to sell?
User avatar
paso750
paso grand pooh-bah
Posts: 5558
Joined: Sun Jul 18, 2004 12:00 am
model: 750 Paso
year: 1987
Location: southern Germany

Re: spark, but no start revisited

Post by paso750 »

I am measuring the voltage on the spark gap and grounding on the bike
You`re measuring the voltage at the spark plug gap? You would measure something between 6.000 and 20.000V if you had spark. Not sure what you`re measuring or better what you intend to verify by measuring this way.

G.
User avatar
DoubleDuc
Posts: 34
Joined: Mon Jul 28, 2014 2:12 am
model: 907 I.E.
year: 1991
Location: Va, USA

Re: spark, but no start revisited

Post by DoubleDuc »

I also tried swapping the ecu's around with same results.

I get a constant 11 & 10.7v from plug wires.
User avatar
higgy
paso grand pooh-bah
Posts: 3327
Joined: Tue Jul 29, 2008 9:50 pm
model: 907 I.E.
year: 1992
Location: Hilltown,Pennsylvania
Contact:

Re: spark, but no start revisited

Post by higgy »

do you have two that you are willing to sell?
I may, let me look this weekend

PM me your snail mail addy, DO NOT post it here :thumbup:
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
User avatar
DoubleDuc
Posts: 34
Joined: Mon Jul 28, 2014 2:12 am
model: 907 I.E.
year: 1991
Location: Va, USA

Re: spark, but no start revisited

Post by DoubleDuc »

For those that may have similar problem: Took it to the Duc Shop, it was the cam/timing sensor.
Post Reply