[Inferno]

Background - I bought a '99 900SSie with 17,082 miles that sat in a storage unit for the past 6 years. I changed the oil, timing belts, and spark plugs. I also replaced the lines for the fuel pump in the tank and cleaned out the filter and filled it back up with 93 with injector cleaner. The previous owner deleted the charcoal canister or whatever the vent line from the gas tank goes to, so I used a T to put that line (which was capped) into the drain line, and I removed the barbs on the engine for the vacuum lines and replaced them with bolts with crush washers and sealant.

The problem - As the bike warms up, it take longer and longer for it to idle down between 4k and 5k RPM. Once the bike gets hot enough, the RPMs will just hang there and I have to drag them back down with the clutch. Also, when the bike is warmed up all the way, if I'm cruising at 4k RPM and try to accelerate hard, the clutch will just slip, even though it is most definitely not worn out. Above 5k and below 4k the RPMs will drop normally, its just in that range.

Any idea what this could be or how I should troubleshoot? I searched and found this thread, but its about a carb'd bike. Do you think I have a lean condition in that range or is it something else? Thanks.

 

[Inferno]

New info:

I just went to do the TPS adjustment, and the numbers weren't moving when I rotated the throttle. After ohming out the two wires from the ECU end of the harness to the TPS end, pin 22 had correct continuity to pin A on the TPS end, but the other one (pin 11) had continuity to pins A and C on the TPS end, as well as gound. If I unplugged the ECU, the pin had continuity only to the correct wire on the TPS end. This tells me that something is wrong with my ECU.

 

[Inferno]

And onto the next complication:

The TPS was off by about 40mv. I got it adjusted properly and the throttle bodies are close to sync'd at 1500ish, but when I rev it, the idle hangs at 2500 and pulls the fluid in my syncing tool way towards the horizontal cylinder. When it does this, the only way I've found to get the idle to drop is to shut it off and restart it. The air bleeder screws are all the way closed too, so that's not the issue.

I'm completely lost at this point. What should I do? Any help is greatly appreciated.

 

[Punch]

This is just the start of my input - late here in Oz and maybe a few too many whiskies under the belt but hey who cares!

You obviously have a multimeter (what we call them in Oz) and an understanding of what should be happening and a wiring diagram.

ECU connected and key on etc. then the ECU supplies 5V (nominal) to the TPS.

This means you should measure 5V between ECU pins 22 and 1 or at the connector between A and B. This is the 5V supply to the TPS.

ECU pin 11 and connector C are the TPS potentiometer "slider" - throttle position.

22/C is the negative from memory, so ECU connected and key on you should see voltage rise with multimeter neg to 22 and multimeter pos to 11 when you twist the throttle open. Similarly ECU disconnected/unplugged, with the multimeter on the resistance scale between A and C or B and C the resistance should change - this is testing the the TPS resistance. If it does not change then the TPS is faulty or there is a fault in the connections/wires somewhere.

Once you have one this quick test, you can determine where the fault may be.

First up, IMO, is working out where then problem comes from, fix that, then worry about adjustments later. BikeBoy.org has info on how to set the TPS

Richard

 

[Inferno]

Thanks for the info Richard. The TPS sensor checked out fine, so the sensor itself is not the issue. I figured out the idle hanging issue (fast idle adjustment screw was in too far), and got the throttle bodies synced relatively well, but when I took the bike for the test ride it was way down on power. It felt like I was riding a bicycle. I hooked everything back up correctly, what could be the issue?

The TPS reading is at 620ish mV but I'm assuming that's due to the balance screw pushing the LHS butterfly. Do I need to redo my TPS adjustment?

 

[Punch]

This link should provide the info you seek rather than me pretend i have all the answers for you!

BikeBoy.org - Ducati 2V Non Linear TPS Baseline Adjustment

 

[Inferno]

I read through that a few times before I did the adjustment.

Today I decided to recheck the spark for the hell of it. Sure enough, the vertical cylinder wasn't getting spark. I tried switching the power wires to the coil and the plug wires and using a different plug, and narrowed it down to the coil being shot. Upon closer inspection, the coil actually had a small crack in it.

Its odd that this happened because I checked spark before I messed with the TPS and throttle bodies and it was fine. I'm not sure if this is a new problem or had something to do with the original problem of the RPMs hanging up...

 

[Inferno]

This thread has gotten kind of old but I figured I should post the solution in case anyone ever has a similar issue. I was out of the state for a few weeks so I didn't get a chance to put the replacement coil on until yesterday. Did that and had an issue where the bike kept shutting off, turns out the fuel pump strainer was torn open and rust flakes were clogging the pump.

A new strainer (one for a 2000 Honda CR-V works and can be had at any auto parts store), getting all of the loose rust out of the tank, and some Seafoam in the fuel fixed the issue. The bike is running much smoother now than when I bought it. I will do the POR 15 treatment to the tank over the winter, but right now I need the bike for transportation. Thanks to everyone for the help!