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Discussion Starter #1
Yesterday I rode my Duc to work and after work, it had trouble firing up. I tried with the "high idle" open, closed, partially open, etc, and nothing worked. The most I got was a few actual combustions which just died off. Eventually, after over a half hour of trying intermittently and with the battery nearly dead, it fired up (reluctantly) and I made it home.

Anyways, to get to the point, I got around to checking it out today. I'm no mechanic, but I know the basics and then some. I took out a plug, I'm getting spark, and the plugs look pretty good. When I press the switch from 'off' to 'run' I can hear the fuel injection prime the cylinders (at least, I think this is what's going on). It seems to me that the bike catches that little bit of fuel that's primed, fires a time or two, then dies off. Maybe the injectors are gummed up and not injecting enough to get it going? I don't know...

I thought I'd drop a thread here to see if anyone has had a similar problem and can give me an answer or some ideas to try or some more troubleshooting techniques. I know this problem is really vague (my bike won't start, what's wrong?!), but maybe with the few clues I have, someone can point me in the right direction.

Thanks, guys.
 

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Open the gas cap and while looking in turn the run switch if the gas in the tank swirled like a toilet flush you've bust a gas line in the tank. The new fuel is eating the hoses and their is a certified hose that needs to be used thier but some folk still don't use it as it can be hard to find
 

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I take that when you press the starter button it triggers the motor right? If nothing happens, this is often the case of the connector behind the soleniod coming lose. Easy fix with a tie wrap.

That said, what you described sounds a bit different.

I think that I had a similar problem on my ST2 when I had an ST2. The problem was with the TPS (Throttle Positioning Sensor). There is a vague suspicion that after a while they go wrong under heat but work when cold. Hence why it plays up when you ride after a while but they gets OK again after you stopped. That said mine also had issues starting the bike from cold.
Changing the TPS solved the issue. Check however how you set up a TPS, it is not just a question of bolting this on. You need to adjust as well.
 

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A little more info may help dismiss a few possibilities.
When was the engine serviced last , Plugs / Fuel Filter / how old is the fuel etc ?
With a split hose (some noise inside the tank can be the pump pressure release valve , particularly loud if low on gas) I would have thought the bike would have run poorly on your return journey home which you did not mention ?
 

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Had something (slightly) similar with my ST2 recently in that I`d turn on ignition - fuel pump would prime but when the start button was pressed - nothing. I`d then have to turn ignition on and off several times and try and start it and it would eventually fire up after almost starting a few times. Went all round the houses with this , new starter solenoid , recharged the battery,checked all connections / earths etc - anyway,to cut a long story short it turned out to be the alarm (datatool system 3 ) Must have been on the way out for a while as the starting problem got worse and worse over the course of a few months - it was very misleading too as sometimes it started right away,other times it could take 15 mins to get it going - once the alarm was by-passed I haven`t looked back - you dont say if you have an alarm fitted but it might be worth a shot.
 

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Discussion Starter #6
Thanks for the advice, you guys are awesome. I went out this afternoon and it started right up, no trouble. Whatever the problem is, it's definitely intermittent and annoying.

Open the gas cap and while looking in turn the run switch if the gas in the tank swirled like a toilet flush you've bust a gas line in the tank. The new fuel is eating the hoses and their is a certified hose that needs to be used thier but some folk still don't use it as it can be hard to find
This doesn't seem to be the issue. I was told the bike has always been run with ethanol free fuel and I run ethanol free in it as well.

I take that when you press the starter button it triggers the motor right? If nothing happens, this is often the case of the connector behind the soleniod coming lose. Easy fix with a tie wrap.

That said, what you described sounds a bit different.

I think that I had a similar problem on my ST2 when I had an ST2. The problem was with the TPS (Throttle Positioning Sensor). There is a vague suspicion that after a while they go wrong under heat but work when cold. Hence why it plays up when you ride after a while but they gets OK again after you stopped. That said mine also had issues starting the bike from cold.
Changing the TPS solved the issue. Check however how you set up a TPS, it is not just a question of bolting this on. You need to adjust as well.
Right, it turns over, but doesn't fire (maybe a time or two, if it does, but dies). I'm not sure if this is the problem, but it's definitely something I'll look at. Where's the TPS located on an ST2?


A little more info may help dismiss a few possibilities.
When was the engine serviced last , Plugs / Fuel Filter / how old is the fuel etc ?
With a split hose (some noise inside the tank can be the pump pressure release valve , particularly loud if low on gas) I would have thought the bike would have run poorly on your return journey home which you did not mention ?
I'm not sure when it was serviced last, the previous owner said he had it maintenanced regularly by a local shop and I have no reason not to believe him. He hadn't had the 12,000 mile maintenance done yet and I just hit 12,000 the other day, so I plan to take it in when I get an opportunity in the coming weeks. If I haven't resolved the issue myself by then, I'll have the shop repair it. The fuel is fresh, plugs look good, not sure about the filter. It doesn't run poorly once it gets started, it just doesn't want to start sometimes and starts a little rough when it does. After getting warmed up, it seems fine.


Had something (slightly) similar with my ST2 recently in that I`d turn on ignition - fuel pump would prime but when the start button was pressed - nothing. I`d then have to turn ignition on and off several times and try and start it and it would eventually fire up after almost starting a few times. Went all round the houses with this , new starter solenoid , recharged the battery,checked all connections / earths etc - anyway,to cut a long story short it turned out to be the alarm (datatool system 3 ) Must have been on the way out for a while as the starting problem got worse and worse over the course of a few months - it was very misleading too as sometimes it started right away,other times it could take 15 mins to get it going - once the alarm was by-passed I haven`t looked back - you dont say if you have an alarm fitted but it might be worth a shot.
No alarm system. It turns over, but won't fire/combust. This doesn't sound relevant to me, but thanks.

Sorry for such a long post, but I wanted to address all of your helpfulness! Thanks!
 

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Is that the first 12,000 Miles coming up (i.e. total mileage) ?
Maybe a new set of plugs are due now ?
I always prefer to go for the simple stuff first before chasing more serious / costly fixes.
 

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Discussion Starter #12
Is that the first 12,000 Miles coming up (i.e. total mileage) ?
Maybe a new set of plugs are due now ?
I always prefer to go for the simple stuff first before chasing more serious / costly fixes.
Yes, first 12,000. I thought plugs, too, but they seem to be decent (brownish, not corroded, etc). I'll be getting them changed with the service either way, though.

Anyone think this could be due to the need of a valve adjustment?
 

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I'm betting its crank position sensor, as Frank suggests. The gap between the sensor and stator has to be just right (~.5-1mm IIRC) or the ECU won't trigger fuel injector pulses and/or spark. If the sensor is borderline on setup or integrity, the behavior will change with temperature, humidity, etc.

If you have the bike denuded, its a good opportunity to clean and lube (with dielectric grease or anti-corrosive) any electrical connectors you can find. These bikes have a lot of connectors and need periodic electrical love and care.

A weak battery will also cause unreliable starting. If the voltage goes low, the bike might crank, but the ECU might not get enough voltage to make decisions (like me, after a few beers...). If the battery is more than 4-5 years old, support the economy by getting a new one.

If you are getting it serviced (hopefully by a proper Ducati shop) soon, that will be an area to check. Any ST2 (you don't mention the year) would be overdue for timing belts if it has not had a 12K since birth, so get that done pronto. Belt failure from age will result in a much bigger no-start condition (one involving pieces of metal).

Have a great summer riding!

pg
DD
 

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Discussion Starter #16
I've floated one on the net for you.
The link is on our little UK site...

ST2 Workshop Manual
You're awesome! I registered, waiting for approval so I can get the link.

I'm betting its crank position sensor, as Frank suggests. The gap between the sensor and stator has to be just right (~.5-1mm IIRC) or the ECU won't trigger fuel injector pulses and/or spark. If the sensor is borderline on setup or integrity, the behavior will change with temperature, humidity, etc.

If you have the bike denuded, its a good opportunity to clean and lube (with dielectric grease or anti-corrosive) any electrical connectors you can find. These bikes have a lot of connectors and need periodic electrical love and care.

A weak battery will also cause unreliable starting. If the voltage goes low, the bike might crank, but the ECU might not get enough voltage to make decisions (like me, after a few beers...). If the battery is more than 4-5 years old, support the economy by getting a new one.

If you are getting it serviced (hopefully by a proper Ducati shop) soon, that will be an area to check. Any ST2 (you don't mention the year) would be overdue for timing belts if it has not had a 12K since birth, so get that done pronto. Belt failure from age will result in a much bigger no-start condition (one involving pieces of metal).

Have a great summer riding!

pg
DD
I see. The CPS definitely sounds like a possibility. I highly doubt it's the battery. The one in it is less than a year old and is a quality battery. Yeah, it is definitely overdue for belts, getting it done very soon. Thanks!


Voltage Regulator
This is a possibility, but it's a 98 with the regulator already relocated on the trees, so that makes it less likely to me, but could still be it.
 

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Spark, fuel and compression in the right amounts and at the right time are needed to run an engine.

If the starting problem is intermittent, but when it runs it runs great, then it is unlikely to be anything like plugs, plug wires, split hoses, battery and the like. Compression is probably out of it too. It wouldn't run right at any time. The problem with trouble shooting an issue like this on an FI bike is the fuel and spark components can be electrical (or electronic). Given the intermittent nature, I would bet a connector or ground issue more closely related to the ECU than anything else. When the problem was happening and you pulled the plugs to check for spark, were they wet with fuel? If not, and I think you said they looked good (and there was spark), then your injectors are not firing. If the CPS was going, I would think the injectors and spark would both fire, just not at the right time. So that leaves an issue with the injectors getting the signal to fire. I doubt they are clogged or dirty, if they were they would not be intermittently dirty, it would be an issue all the time. So, again we are looking at electrical. It is probably time to pull all the plastic and check all the connectors for corrosion or looseness. Worse case is going to be the ECU going out.

Best I can guess at with the info given and only one cup of coffee…
 

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Had something (slightly) similar with my ST2 recently in that I`d turn on ignition - fuel pump would prime but when the start button was pressed - nothing. I`d then have to turn ignition on and off several times and try and start it and it would eventually fire up after almost starting a few times. Went all round the houses with this , new starter solenoid , recharged the battery,checked all connections / earths etc - anyway,to cut a long story short it turned out to be the alarm (datatool system 3 ) Must have been on the way out for a while as the starting problem got worse and worse over the course of a few months - it was very misleading too as sometimes it started right away,other times it could take 15 mins to get it going - once the alarm was by-passed I haven`t looked back - you dont say if you have an alarm fitted but it might be worth a shot.
If it wasn't the alarm, those symptons do point out to the soleniod connector to the starter motor. Pretty disconcerting when it happens but easy enough to fix with a tie wrap
 

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CPS sounds like a good thing to check here.
Note, he says it cranks over OK when touching the button, so it's probably not the solenoid connector.

Another thing it could be is starting technique. Sometimes it need you to apply just the correct low throttle setting (like just above where the throttle cable gets taught). My ST4s loves that spot, but my ST2 was different (and I forget "what exactly" it was like!)
 
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