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Discussion Starter #1
My 998 quit on me today. I need help figuring this one out. I'm riding out to Moto-GP at Indy next weekend with a bunch of guys and I don't intend to miss it!
I just finished going over it. re-checked valves done 800 miles ago(it was my first time so I wanted to see if they would "bed in" at all), changed fuel filter to the Napa version that LT Snyder recommends and generally went over all the electrical connections and sensors to make sure all was well. Changed oil and coolant again.

Problem first started after a ride on memorial day, we got rained on pretty bad and the tach went nuts, then later every time I'd roll into the throttle hard, especially at low RPM she would backfire until I rolled out of it and downshifted to get the RPM's up. Twice it just quit altogether. It would always restart immediately after I stopped however. These problems seemed to clear up mostly, I went over many of the sensors to make sure they weren't retaining water and all was well. The tach continued to not function properly. BTW, yes I checked the brass screws, they're all tight.

During this recent service I discovered the battery connections and ECM ground had become corroded, not bad, just a bit, and the battery connections were loose.
I corrected these items, put some dielectric on the battery terminals once everything was connected to ensure it wouldn't compromise the connection.

I took her out for a shakedown and she ran flawlessly for about 4 miles and then just quit. No drama, no backfire, even the tach was acting right again, then it just stopped running. I wasn't in the throttle, I was cruising at approx 45MPH about to turn into the gas station. While waiting for the trailer to show up I began working on her. I found the main charging fuse (large 40A fuse next to relays under battery) is blown. I bypassed it with some copper wire I had, no dice. The infamous "white connector" for the regulator looks fine. I disconnected it which should have made the bike run off of battery alone I think, again no dice. I may have pinched a wire behind the battery box when I put everything back together but I haven't confirmed this yet.
Any suggestions on what else it may be?
Even without the charging system it should run on battery alone right?
All other fuses are fine, a blown charging fuse should only have lit the charging fail light right?
 

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Discussion Starter #2
let me add a few more things I left out.
I can hear the fuel pump come on and prime.
The starter is turning the motor over easily however it doesn't even sound like it wants to fire. It's as if the ignition is off.
 

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Discussion Starter #3
update:
No pinched or burned wires anywhere.
All fuses except for main fuse are fine visually.
according to shop manual the main fuse protects the wire between the Regulator and both the battery and main fuse group. Checked for a ground fault on this wire and no luck. Can the regulator fail by shorting internally and allowing the battery to backfeed into to blow the main fuse? Other than this I don't see how the main fuse blew but all the others are fine.
I'm sure I have another problem anyway since I jumpered the main fuse socket while I was stuck in an attempt to limp home. This did nothing.
I will check for spark first thing in the AM.
Does anyone have any ideas on where I should look?
 

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Discussion Starter #4
it has spark. vertical looked weeker than horizontal but should be enough to fire. I'm moving on to trying to turn the gas tank around backwards and see if injectors are spraying.
Just curious, will I be able to find the 40A main fuse locally?
 

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Discussion Starter #5
OK it runs now. Fuel line from pump to filter wasn't tight enough (sure thought it was, needs a lot of torque I suppose) and popped loose. Fuel was just sort of sputtering out of injectors with tank turned around. after fixing that fuel spray was a nice fine mist I thought I should see.
The remaining question is the main fuse. What could have caused that? I have it jumpered right now just to get it to fire but I obviously can't leave it that way for long. I'm going to try to find a new fuse today but I'm concerned, I have a long ride next weekend and I'm not trusting the bike right now.
 

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How sure are you that the fuel line connections inside of the tank is OK?
Was a TPS reset done at the last service?
Did you check all exhaust connections?
Belt tension still OK after the service?

No idea or suggestion on the blown fuse issue. If it was me I would have replaced all the relays and packed a spare for just in case. But that is me.

These things are usually a small little piece of detail that was overlooked and is giving you uphill now just because it can. Just got to find that little sucker.....

SF
 

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Discussion Starter #7
Fish,
It was a line in the tank, apparently not tight enough and it popped off.
Found another fuse at AutoZone, but still no idea why it blew. I swapped the main and ignition relays as a part of the troubleshooting, but didn't seem to make a difference.
The odd part about the fuse is that it only seems to protect from the regulator to the battery and main fuse block. Everything else is downstream of the fuse block and should therefore pop one of the smaller fuses. Unless one circuit was heavily loaded and the combined load of it plus the other accessories exceeded the 40A but I think that's a stretch.
I would think a hose coming off of the fuel pump would remove all the load from the pump and therefore drop it's current draw, not increase it anyway.
 

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Discussion Starter #8
Oh yeah I forgot,
Haven't ever touched the TPS, don't have the tools to set it.
Belt tension was readjusted when valves were re-done. Tension set to 90 Hz (used belts w 800 miles on them).
 
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