Ducati S2R1000 - barely runs and runs rough

[SwiftTone]

I did a valve adjustment and took it for a ride. Everything ran fine. The next day I replaced the fuel filter as it was having an existing issue of running to redline at full throttle. It would rev up fine at full throttle up until 6500rpm then fall on its face and not be able to increase the RPM. So I replaced the fuel filter. There was an aftermarket filter in there. The little wire (grounding?) was attached to the metal body of the filter with a hose clam since that filter didn’t have a little tab for it. I put in the new OEM filter and attached the little wire snugly with stainless safety wire to where it belongs. What is this little wire for?

I put everything back together and it wouldn’t start. It would just crank and crank. Occasionally it would fire up for 1 revolution, but then go back to cranking. I primed the fuel pump a few times and same thing. I pulled the spark plugs and it was a little damp. I dried it off and reinstalled. Same thing. I detached the outlet hose of the fuel pump flange, turned on ignition and confirmed fuel does in fact flow.

Next day I took the fuel pump assembly back out, confirmed everything was still in place. Also removed the hoses that attach to the fuel filter, blew through it and confirmed that it was not clogged and that it was installed in the right direction. Put the assembly back in and unplugged the wiring for it. I pulled the spark plugs again, and with the plug wire still attached, grounded it to the exhaust pipe and crank it and I could see visible blue sparks as it fired. I used the engine turning tool and set horizontal cylinder at TDC from the flywheel side, then confirmed that the timing marks were aligned at the pulley side. Put everything back together and attempted to start again. This time the engine seemed to be able to fire up for a few more revs then die. I was able to keep the engine running by adding a little input at the throttle. When it did run it ran really rough and didn’t sound good. If I gave it more throttle than say 15%, it would die out. Also, if I give it too much throttle as it cranks, it would make a loud pop and puff something out of the air filter through the open lid.

I’m stomped at what the issue could be. What should I test next? I have read that it could be a TPS. I have a multimeter. How do I test the TPS?

To sum it up:
•Has fuel
•Has spark
•Has compression
•Good timing

Whats next?

[cdovego]

Sounds like TPS sensor to me - did you recently ride in the rain?

I've had bad luck with Ducati TPS sensors so I may just be jaded.

[cdovego]

Also, if you're hell bent on avoiding shops - check in with ScottieDucati...he's just down the road from you and is a good resource when he has free time.

[scottieducati]

Hey I resemble that remark.... Unfortunately, not only are both lifts occupied with projects that desperately need to get done and I don't even have the time to get to those right now

[SwiftTone]

Also, if you're hell bent on avoiding shops - check in with ScottieDucati...he's just down the road from you and is a good resource when he has free time.

Hey I resemble that remark.... Unfortunately, not only are both lifts occupied with projects that desperately need to get done and I don't even have the time to get to those right now

At this point I'm just looking for guidance for where to look next. I'm just frustrated that this started immediately after replacing the fuel filter and seem to not have anything in common.

Also, the bike didn't touch water between doing the valves, riding, and fuel filter replacement.

[scottieducati]

It's gotta be electrical. Either a loose connection or bad TPS. Hell we got a replacement TPS that was bad out of the box once.

[scottieducati]

This help by any chance? Had a fuel hose pop off the filter on my ST2 not long ago...

[Trajiks9]

The bike is surely running rich when you let me ride it. Take a look at the cylinder head temp sensor (on the horizontal intake valve cover), unplug the sensor and see if the connectors are corroded. If they are green you may be able to clean them up and the bike will lean out, if the connection is corroded the bike will run rich. Which might be the underlying issue.

[SwiftTone]

Just checked the TPS. The signal wire on the connector was slightly frayed exposing some wire underneath. I taped it up and still no start. Then tested the volt range on the TPS itself from closed throttle to open throttle. The readings were 0.39V to 4.20V with gradual increases as I rolled on the throttle.

Also checked the connection on the cylinder head temp sensor. Looked good with zero corrosion.

This shit sucks. I'm temped now to open up the fuel tank (again) and throw in the old fuel filter to see what happens. Am I going crazy?

[golden chicken]

Did you set TDC on compression or on exhaust stroke? Does it matter? It might.

[South of Heaven]

It's a Ducati; what do you expect??! I'm speaking from experience as a disgruntled, former Duc owner. They are junk.

Sorry for derailing your thread. Feel free to tell me to go bleep myself! I'll crawl back into my hole now. LMFAO

[Fitron]

Judging by the symptom you described as not being able to rev past 6500 rpm...it was definitely encountering a LEAN condition, not rich. I would have started at the fuel filter, like you did. I think that after cranking and cranking, the plugs should have been dripping with fuel...not just damp. You're not going crazy...my next move would be to put the old fuel filter in there. Check this out:

Weird priming problem after fuel filter change - Ducati.ms - The Ultimate Ducati Forum

[PhilB]

It's a Ducati; what do you expect??! I'm speaking from experience as a disgruntled, former Duc owner. They are junk.

Sorry for derailing your thread. Feel free to tell me to go bleep myself! I'll crawl back into my hole now. LMFAO

They are not inherently junk in general, but they can easily *become* junk if neglected or abused, or worked on/modified by people who don't know what they are doing. OTOH, get one that is in good condition and has been cared for, and do the maintenance somewhere near the recommended schedule, and they can be magic.

I'm speaking from experience as a very gruntled, current Duc owner.

PhilB

[timmyho414]

Fuel pump?

my 749 shit the bed and it won't pull hard. It would sit an idle just fine. It swapped the pump from my 748 and its been good. The motion of replacing the filter(I've never actually seen on be the cause if an driveablity issues on a car) may have been the last straw.

pull one of the lines and see if it has pressure. No idea what the spec is, id guess in the 40psi range. Just because its spinning doesn't mean is pumping.

plus if the pressure is low it will still get the plug wet but its just dripping out and not spaying like it should to atomize the fuel.

[SwiftTone]

Okay so...little progress.

I primed the pump 30 times to pump the fuel all the way through from the output to the input hose, and I wasn't able to get it running. Then I sprayed intake manifold cleaner into the throttle bodies and it actually ran! As long as I kept feeding it through the throttle bodies it ran and actually got it up to 140 degrees F. So it def isn't a spark issue.

Next I disconnected the return hose and see what the fuel flow was like. Primed and let whatever comes out go into a container. Seems like very little fuel flow. 1-2oz per prime. I've attached a video below. Next I connected the fuel pressure tester between the return hose and input nipple on the flange. prime it a bunch of times until it got pressure. It was only able to build pressure to 5psi and once it stopped priming it would drop down to 0psi. To eliminate the possibility of leakage outside the fuel tank, I then connected the fuel pressure tester at the output nipple on the flange, only this time I plugged the end of the hose with my finger. Same results. 5psi when priming and quicking dropping off. I've attached video of this as well.

So this leads me to believe that it's something inside the actual gas tank that is faulty. I've already checked twice and made sure the hose clamps are tight. The hoses in there are the plastic type so it doens't need replacement unless its cracked. If it's a faulty fuel pressure regulator, the pressure would be too high right? So does this mean that it's the fuel pump itself?

I feel like I'm getting close! Thanks all!

Fuel pressure video: Fuel pressure - YouTube
Fuel flow video: Fuel flow - YouTube

[PhilB]

Yeah, I'd bet fuel pump.

PhilB

[SwiftTone]

What component inside the fuel tank actually holds the fuel pressure once it's build up? There is a valve somewhere?

[Fitron]

If it's similar to a car fuel pump, there's a check valve inside the pump assembly. Usually consists of a diaphragm and spring. Also remember, the fuel injectors hold pressure on the other end of the system!

[PhilB]

I'd expect inside the pump itself. It pumps until the pressure needed is achieved, and then holds it, pumping as needed to maintain the pressure.

PhilB

[scottieducati]

Also FWIW, old-gas can kill: fuel pumps and as a result, batteries (clogged fuel pumps pull more draw)... they can even lead to fried electrics, fuses or regulator / rectifiers..... the joys of sugar in our fuel.....

[SwiftTone]

I'm going to replace the hoses first since a loose or cracked hose can cause poor flow and lose pressure as well.

[Fitron]

I'd go this route at the same time:

Kemso High Performance Fuel Pump Ducati Monster S2R 1000 D 2005 2008 | eBay

[SwiftTone]

I'd go this route at the same time:

Kemso High Performance Fuel Pump Ducati Monster S2R 1000 D 2005 2008 | eBay

Do you have experience with this pump? Not much info online and no website either.

[Not Sure]

You have way more patience than me buddy, I give you credit. But then again I don't have much patience. I would have traded it in already.

[number9]

What component inside the fuel tank actually holds the fuel pressure once it's build up? There is a valve somewhere?

Wouldn't that depend on if its a return or returnless system?