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One more angle on fuel filters
These bikes have mediocre 300 watt alternators barely enough to keep the battery charged. A clogged fuel filter will make it even worse as the fuel pump will load the systems down even further.

add to that equation 20+ year old wiring and terminals and you are lucky if it runs at all with the stock wiring.
So take note and always keep those filters fresh and don't forget the filter matters when looking for the source of your recently dead battery,fried fuelpump
or many other electrical gremlins

therefore think wisely if you want to switch on the lights
It`s not good but luckily not that bad either

therefore think wisely if you want to switch on the lights
It`s not good but luckily not that bad either

smart ass

well...first up - the bike will run FINE with about 1/2 a pound of crud in the filter.
if fuel flows - it goes.
I guess it could starve under certain semi-blocked conditions but it should die in a running out of fuel manner, not just a sudden "eeep". Similarly, it should give a starve situation at lower revs with higher load (like with a pillion up hill). I would test if fuel flows at any reasonable rate through the filter...if so, move to the next step...

the ECU and fuel system is open circuit so it's not a sensor detecting any mixture leaning - and if this was the case the exhausts should tell the story.

The TPS cannot be "re-wired"; that's just shop crap for "we don't know...and you're a dumb prick..."
The TPS can be easily tested at home with multi-meter; highly unlikely it will cause a stall at higher running speed..

the bike will run without alternator; un-plug it and see if you like, but so long as the battery has about 8 volts it will run.

My guess is the ignition relays; they are prone to two things:
1. they get a heap of dust collecting underneath on the terminal connectors (not desirable)
2. the spade connectors tend to push loose out of the plastic holder - bad or intermittant connection
while neither of these will necessarily cause a stall they could contribute to a sick relay. That in itself can cause a stall.
You have to get your head right in under and check the clips are on the spade terminals. Give it a birthday and a few NEW relays...they cost about $5 each; lash out!!

the relays are in the ignition circuit and provide power for spark; no spark, no go.
while you are at it you could also check the earth lead for the ignitors...the connector (black wire) is prone to corrosion - because of dissimilar metals (steel to aluminium) and yes - it will be heat affected by high performance 5500 RPM riding.
The ignitors MUST have good earthing and cooling or they will play up and even burn out.
I have burnt one by bad connection to the coil; it blew a hole right through the ignitor casing.

take care and clean the contacts; the bike is 20 years old...and Ducati electrics have never been great.
I would suggest you leave the Weber P7 ECU and chip to last; these are least likely to fail...not bullet proof but certainly the least complained about component on the bike.

finally...give it 2 new plug leads; they screw into the coils and are easy to replace...or if you're a cheap-skate at least test the old ones for ohms and continuity - if they are different replace them.

good luck!!

Finally got the Paso back from Lexington Motorsports. Long story short they had it for 7 months and didn't do a thing except loose the custom fasteners that I had on it. They didn't even fix the fork seals. Good news is that they didn't charge me anything. Found a local Ducati mechanic that said he loves challenge. Hopefully this will resolve the problem.

i would remove the eprom from the ecu and refit a couple of times to clean the pins and sockets.

a blocked fuel filter can give a sudden cut issue. doens't make any sense, but it happens. also fuel flow does depend on rpm. while it might get the same fuel per cycle at 3,000 rpm wot as 6,000 rpm, the rpm is doubled so the fuel injected and flow are doubled. filter issues can be quite wacky. replace it as a first matter of course, move on if issue is still there.

replace relays or remove and hardwire for testing. just because they click means nothing.

is the voltage regulator solid mounted or rubber mounted? whatever it is, change it to the other and see if that helps.

In the next couple of days I should know if the Paso will run well again. The injectors were sent off and were 16% clogged. The fuel lines going to the injectors were dry rotted and cracked. New fork seals and brake pads. The Lexington mechanic jammed the fork seals in with a screw driver and ruined brand new seals. Today the bike is being put back together and we should find out if it fixed the problem. Just in time as I will be leaving for the west coast to guide some Edelweiss tours. So she'll have to sit for a while until I get back, but at least its progress.

It`s good to know that there`ll still shops that give you a job if you`re lefthanded and incompetent

One thing to try is the water temp sensor. Really. I did a similar chasing on my ST2, which is very similar. The temp sensor was flaky and would flop back and forth once I put a meter on it to see what was happening. Before that I changed the fuel lines, fuel filter, cleaned the ignition pickup, new coil wires, a couple of relays, cleaned all the electrical connectors and some other things I can't remember. Chased that for months one lovely summer. The temp sensor tells the computer that the engine is cold or hot, and when it failed, it told it the motor was stone cold and ran horribly. Then it would clean up, then bog again for no known reason. When I measured it in the garage, it was fine. It was only when I put a meter on it, and put the meter in my tank bag to see the wild and erratic swings. Its worth a try. You have chased after everything else so far (except the ECU). And they are cheap on e-bay.

That's my thought of the day.

Cheers,

Well, the bike was put back together with clean injectors and new fuel lines. Now the front cylinder will not run because its being flooded. There's pure fuel coming out of the front cylinder head. So the next step is opening up the front cylinder to make sure its not mechanical. If that checks out OK then its time to find a used ECU and the two sensors that are on the air box by the seat. So, if anyone know where I can get these it would be greatly appreciated.

There are definitely ghosts in that machine. Disconnect the ECU and the battery, give everyone a time out, clean the connections, and reassemble. you can test the injectors to see if they are hanging open, and there should be a way to see if the ECU is sending pulses to the injectors, and not a steady voltage. I think its in your injectors, but I'm just guessing.
Anyone know how different the injectors are from later models like the ST2? Are they interchangeable?

Cheers,
Phil

The injectors from the 907ie and the ST2 have the same part number - 28040021A

You do have spark on fr cyl?

It should run a little rich but OK if a sensor is failing,
ECU goes into limp home mode.
FHE by accident, my Air T loosened.

Tamburinifan wrote:You do have spark on fr cyl?

It should run a little rich but OK if a sensor is failing,
ECU goes into limp home mode.
FHE by accident, my Air T loosened.

Yes, the front cylinder is getting good spark. If we could only find the sensors to replace the old ones. Is there maybe another current sensor that would work? Does the ST2 have the same sensors?

Fast Eddie wrote:

Tamburinifan wrote:You do have spark on fr cyl?

It should run a little rich but OK if a sensor is failing,
ECU goes into limp home mode.
FHE by accident, my Air T loosened.

Yes, the front cylinder is getting good spark. If we could only find the sensors to replace the old ones. Is there maybe another current sensor that would work? Does the ST2 have the same sensors?

The pressure sensor is the same - Part No. 552.4.002.1A, but the air temperature sensor is different.
I doubt if the fault is with the sensors. You could unplugging one at a time to see if there is any differences. The ECU will substitute dummy values that should allow the bike to run, although not at the optimum performance.
I'd also suggest that you try swapping the cable to the injectors. The bike should still run although the injection timing may not be ideal. If the front cylinder now fires and the vertical doesn't the fault lies with the ECU. If the front cylinder still doesn't fire then it's the injector - unless there is a mechanical problem affecting the compression.