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Wasted Weekend Wondering about my Wounded ST3

Tigho's Naked Ducati ST3 in the barn, assessing electrical problems “EFI Er. 1.1” and “Er. 3.1.”
Part 1: It’s a long way, to Pennsyltucky…
My Monster has been incredibly reliable.  The carbed engine has been bulletproof over the last 7,000 miles (on the cusp of 20K total), and I haven’t had any issues that have given Ducati questionable reputations in the past.  The computer system on my ST3 could be another matter.
I rode to work on Friday morning, and was a little over-eager to hit the road.  There was either gravel in the street, or I’m not used to the kickstand yet; and I dumped the new bike in slow-motion like a stupid rookie.

I managed to pull the bike up almost immediately, and sheepishly rode to work.  There was virtually no body damage, but when I turned the bike on, the EOBD (check engine) light was on, the coolant temperature wouldn’t register, and the fan wouldn't shut off.  I scoured some forums, and came to the conclusion that I had damaged the coolant sensor, and that I could probably ride down to Pennsylvania to see my brother later that day, as this was my plan for the afternoon all week.

After work, at the entrance gate to the Holland Tunnel, the engine started sputtering, and the engine wouldn’t engage when heavily twisting the throttle.  I couldn’t turn around in merging traffic, so I decided to limp over to Jersey City, and then in an anxious fit of reckless bravery/idiocy, to see how far I could go before having the issue again.  After I got on the Pulaski Skyway, the bike felt fine for two hours, and I was hoping cleaning or drying the sensor would resolve the issue.

Ducati ST3 in pieces trying to find electrical problems “EFI Er. 1.1” and “Er. 3.1.”I pulled up to a stoplight somewhere around Boyertown, absentmindedly revving the 1000cc engine behind an old Chevy Truck sporting stickers for some sort of nitrous setup, who of course presumed I was intending to race.  Forgetting that I was limping home, I pulled up next to the truck, and when the light turned green, he sped off while the ST3 wouldn’t do more than 35-40mph, while the tach bounced wildly between 6-8000rpms, seemingly disengaged from the engine almost entirely.
Ducati ST3 EOBD Light on parked at Martin's Motorsports in Boyertown PA

The ST3 should do double that speed in second gear, and I had cruised around 85-90 for most of the journey.    I also noticed that I needed to fully engage the choke for it to idle around 3000rpms, and if I turned the choke off, it would stall.  At this point I got really worried that there was a serious issue or even multiple problems. I pulled into the family driveway feeling lucky to get home with both my body and my bike intact.

Part 2: Piecing together the Desmo Details:
Upon arriving home, I spent the next hour taking the farings off my bike with an allen key set I ride with, and came to a couple quick revelations, the first of which was that I needed to ride with a decent socket set for a fully-faired bike.  The next couple realizations I made were that a few hoses looked out of place, and that the mounting bracket holding the secondary (oil) radiator were cracked.  After checking all the sensors and a few calls to family/friends more knowledgeable about Ducatis than I, I had several potential diagnoses as to the cause of my problems:
       1.       The bike has a tip sensor; which puts the bike into some sort of ‘limp mode.’   
2     2.       Tipping the bike caused gasoline to run back up into the charcoal canister, causing the fuel mixture to be unregulated.
       3.       The temperature sensor was indeed damaged, and the bike was permanently in a ‘limp mode’ until the computer got a functional reading.
Finally, my brother in law realized I might need the Red Key to reset the ECU.
Two Ducatis and nothing to ride (Tigho Monster and ST3) Ducati ST3 in pieces trying to find electrical problems “EFI Er. 1.1” and “Er. 3.1.”

Acting on further advice, I unplugged the battery, hoping the bike was indeed ok, and that this would reset the computer.  I then decided to check the air filter, which I intended to do upon first purchasing the bike, and found what I thought was the definitive issue. The K&N style filter was covered in mouse-droppings, and though they didn’t chew through the mesh, this could be the cause of the engine/throttle/idle issue.  I ran out to get a filter cleaning kit; and put off starting the bike up again until the Sunday morning, as the filter takes a good 8 hours to dry, and I needed to get to my little brother's birthday party.

I woke up at 7am this morning, and went out to put the filter back in the bike, and plug the battery back in.  To my absolute amazement, the ST3 EOBD light was off, and the bike started right up.  The idle seemed better, and I happily let it run on the center-stand for twenty minutes before turning it off, and excitedly started to put the fairings back on. I started packing up my things, rocked it off the center stand, and restarted the bike, only to have the fan kick back in and the light go back on.

Crestfallen and even more perplexed, I went back to the manual, and realized I could access the Ducati error codes from the dash.  Holding in the “A” button and then turning on the ignition, the dash alternated two codes “EFI Er. 1.1” and “Er. 3.1.” According to the shop manual and numerous online Ducati forums, they mean “throttle position sensor short-circuit” to the battery and “water temp sensor short-circuit” to the battery respectively.
Ducati ST3 Workshop Manual and  electrical problems Error Codes “EFI Er. 1.1” and “Er. 3.1.”

The fact that there are multiple alternating error codes suggest that maybe it’s not a sensor issue at all, and that perhaps some wiring has corroded, or those aforementioned mice chewed through something.  I spent the rest of the morning looking for wire damage (didn’t find much), but the only thing I found was a cracked connector.

As my bike sits in pieces in PA (and I write this on a bus back to NYC), my next steps are to buy some Dialectric grease and go back to PA next weekend with the Red Key, and hope that my friends and I can find some answers.
© 2013 Tigh Loughhead


Rides gone by...