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Hi guys , started my st4 this morning ,it ran for about 10 seconds and then quit , will crank but no signs of starting at all.
history, has been running great , 7000 miles, within 1000 miles has had belts, valve adjust , fuel filter and lines, plugs ect.

I purchased it with arrow exhaust , it has a chip in the ecu, I have the stock chip, where would you start?
 

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The days are getting longer!
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Fuel pump running?

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Discussion Starter · #3 ·
yes , and I did switch the relays around , I had to get to work so I am going to look at it tonight , first I will check for spark, and then if there is spark then I will make sure a fuel line didn't come loose in the tank, I saw on another thread that disconnecting the battery could reset things? just looking for some advise before I dig into it, thanks
 

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Life is too short to worry !
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I woudl suspect a line has become detached after fitting the new ones , happened to somebody else only a short while ago.
 

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Discussion Starter · #5 ·
I hope that's what it is , that would be easy, although it didn't act like it was running out of gas before it shut off , and it doesn't try to start up at all, it just cranks over.
 

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If a hose came off or split, you will see/hear the gas splashing around in the tank when the bike is turned on, filler cap open. If it's not that, I'm inclined to say those are the symptoms of a swarfed up Crank Position Sensor, other than it started up and then died, but the turning over and not sparking all of a sudden/out of the blue, sure sounds like the CPS should be pulled and cleaned off. It's the sensor to the left of the water pump, behind the hoses. It can be pulled out and replaced with the hoses attached, but not without some dififculty. It may be worth a try. :)
 

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Discussion Starter · #7 ·
If a hose came off or split, you will see/hear the gas splashing around in the tank when the bike is turned on, filler cap open. If it's not that, I'm inclined to say those are the symptoms of a swarfed up Crank Position Sensor, other than it started up and then died, but the turning over and not sparking all of a sudden/out of the blue, sure sounds like the CPS should be pulled and cleaned off. It's the sensor to the left of the water pump, behind the hoses. It can be pulled out and replaced with the hoses attached, but not without some dififculty. It may be worth a try. :)
would I see spark to the plugs if the sensor were mess up?
 

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Discussion Starter · #9 ·
from what you said they must get dirty ? I will check that out first if no spark, thank you
 

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would I see spark to the plugs if the sensor were mess up?

No, that's what triggers the ecu to fire the plugs

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I clean mine annually as part of my PM program when I put the bike away for winter storage, so it might be worth the effort to clean it off even if it's not the issue in order to avoid/help reduce the prospects of a CPS non-starting issue in the future. :)
 

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Discussion Starter · #11 ·
I clean mine annually as part of my PM program when I put the bike away for winter storage, so it might be worth the effort to clean it off even if it's not the issue in order to avoid/help reduce the prospects of a CPS non-starting issue in the future. :)
Thank you, I will take that to heart and make it part of my services.
 

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Discussion Starter · #12 ·
I was looking up that sensor , is it also called a timing rpm sensor, ducati part number 552-4-020-1a? looks like it is a black plastic, held in with one screw.
 

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Yep. An there seems to be more realistically priced ones comming on the market. Check out the parts sticky.

Have a good one.
 

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Discussion Starter · #14 ·
no spark

ok, pulled plugs and no spark, took out the cps and cleaned it off, looked ok, still no spark, checked all fuses , disconnected battery and still no spark, any help would be greatly appreciated,
 

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Discussion Starter · #15 ·
No spark

I did an earlier post this morning when I tried to start my 2000 st4 and it started fine then died, it will crank over fine but makes no atempt to start. Since then I have checked for spark at the plugs and there is none , I removed the cps and cleaned it , it looked ok, changed all the relays arround, disconnected and reconnected the battery, tried putting my stock chip in the ecu, checked all fuses, don't know where to go from here, any suggestions
 

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I did an earlier post this morning when I tried to start my 2000 st4 and it started fine then died, it will crank over fine but makes no atempt to start. Since then I have checked for spark at the plugs and there is none , I removed the cps and cleaned it , it looked ok, changed all the relays arround, disconnected and reconnected the battery, tried putting my stock chip in the ecu, checked all fuses, don't know where to go from here, any suggestions
Have to ask: Did you ground the plug against the engine with a block of wood or other insulated tool when you cranked it over?
 

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Discussion Starter · #17 ·
don't blame you for asking, yes I did
 

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Mr Leakered
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Do you have a shim between the cps and crankcase? If so, try removing it. Even though there is a recommended gap, a wafer thin gap is best as it is just an induction sensor.

As an internet diagnosis, if you have no spark on either plug, your best early bet is a cps replacement.

Have a good one.
 

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Discussion Starter · #19 ·
Thanks , yes there was a shim, I was looking through LTs manual for the st and see a ohms test for the sensor, I am going to pull it again and test it for that. I guess if i can't find anything I will check every wire in that system to make sure nothing is pinched or broken, then I will start with a new sensor, I hate this crap!
 

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Ducati Designs
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I'm trying to recall from my 2000 ST2 (Deerslayer 1); IIRC, the starter would crank with the run/stop switch OFF and/or sidestand down, just no fuel pump or spark, whereas later years, they would not even crank in that condition. Am I recalling incorrectly?

pg
DD
 
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