Ducati.ms - The Ultimate Ducati Forum banner
  • Hey Everyone! Enter your bike HERE to be a part of this months Bike of the Month Challenge!

1 - 17 of 17 Posts

·
Registered
Joined
·
102 Posts
Discussion Starter · #1 ·
Been cranking it and it's not showing any life. I was having some issues last fall with it not wanting to start but after several key on/off cycles it would eventually start. After no signs of life and 4 cranking sessions over 4 days tonight I got a backfire. Granted, it's been in a garage just above freezing, but I'd expect some signs of trying to start.

Where do I start? Web searches haven't helped much at all.
 

·
Registered
Joined
·
355 Posts
What's the valve clearances like?
Other thing to check is for weak spark.
 

·
Premium Member
Joined
·
5,676 Posts
Helps to know what work, if any, was done to it just before the trouble began.

In general you need three things for an engine to run. Properly timed spark, fuel and compression. First step is to find what you're missing.

It may be pretty simple, split fuel line, clogged filter, failing pump for fuel. Bad plugs, coils or wires for spark. Either could be more complicated like a bad ECU or corroded connection somewhere in the harness.

If compression, least likely but needs to be considered, valve timing, bent valve, burnt valve, holed piston...

Not knowing if any work was done makes it hard to trouble guess over the internet, but if you can at least find a starting point maybe you'll get to it with little drama.

For a bike that's been sitting, I'd start with fuel first.

Edit... I guess there is kind of a 4th thing needed in the case of most vehicles. Clean flow of air to mix with that fuel! Maybe check that a family of mice haven't taken up residence in your air box.
 

·
Registered
Joined
·
102 Posts
Discussion Starter · #5 ·
Helps to know what work, if any, was done to it just before the trouble began.

In general you need three things for an engine to run. Properly timed spark, fuel and compression. First step is to find what you're missing.

It may be pretty simple, split fuel line, clogged filter, failing pump for fuel. Bad plugs, coils or wires for spark. Either could be more complicated like a bad ECU or corroded connection somewhere in the harness.

If compression, least likely but needs to be considered, valve timing, bent valve, burnt valve, holed piston...

Not knowing if any work was done makes it hard to trouble guess over the internet, but if you can at least find a starting point maybe you'll get to it with little drama.

For a bike that's been sitting, I'd start with fuel first.

Edit... I guess there is kind of a 4th thing needed in the case of most vehicles. Clean flow of air to mix with that fuel! Maybe check that a family of mice haven't taken up residence in your air box.
Well, it ran last October but was getting increasingly hard to start. Valves and all were done 1500 miles ago. Engine turns evenly, so unlikely to be compression or valve. Fuel pump pressurizes, or at least makes the effort to do so upon key on. I'll check the airbox, but that's unlikely.

I bought another ECU and a programmer this past winter but was hoping to get a start before messing around with that. Reason is that it would spin and not fire, I'd cycle the key, try, cycle, try, and usually on the second or third try it would start like nothing was wrong. Sometimes it would take four or five, but it would start. Not this spring.

The upside is that when the snow is gone the Triumph is ready to go. I'll have time to sort this out, but it's going to impede the 900SS redo.
 

·
Registered
Joined
·
355 Posts
Big backfire indicates that you have some spark and fuel but it's happening at the wrong time. This can occur is valves are to tight and would also explain hard starting when last run. It could also be faulty crank angle sensor, slipped belts etc. But I would check valves first.
 

·
Registered
Joined
·
7,368 Posts
First check the airbox. After you’ve cranked it a bit pull the plugs and ground them. They should be wet and smell like fuel . Crank it over and check for spark.put your finger in each plug hole and crank. It should blow your finger out. Check your ground connections and clean them all. Check battery voltage. Take all your fuses out and clean the ends. Spray your cpu connectors.
 

·
Premium Member
Joined
·
5,676 Posts
As duc96cr alludes to, you still need to find out what's missing. I agree miss-adjusted valves can cause a running issue, but to cause something as described, I don't think so. Maybe poor low speed running, but not a no start condition. I'd verify valve timing for sure, off a tooth or two is not so good.

What brings me back to fueling (which really includes intake air supply), is the degrading nature of the problem. Thinking filters, and such. If you said it was fine, I adjusted the valves and then it wouldn't start, you be in a better place to isolate this.

Start somewhere. Lift the tank, pull the plug wires, pull the air box top and the crank the engine with the throttle held wide open. You should see fuel squirting, it's not a nice spray pattern, from the injectors. Check the video of my bike linked. That's what it should look like. If it looks weak or not there, spray a shot of starting fluid in the TB. Should at least try to catch. If it does, look to the filter (including the sump screen at the pump intake), or the infamous split fuel line at the pump's output as two high probability items.

If there is fuel but still no start, move on to spark.

The other oddity is you say the bike would eventually run after cycling the ignition a few times. That may really kill any possibilities listed above.

Maybe check the the ground on the ECU. Should be a black ground wire connected to one of the ECU mounting bolts. If the pump comes on each time you cycle the key, then it's probably not a relay. You could try the ECU ground problem work-around by grounding it at the test plug. A few have fried the ECU internal ground and had luck running the bike grounded at the plug.

Video.
 

·
Registered
Joined
·
7,368 Posts
I don’t know how good the ecu ground is on that model, but I wasn’t happy with one of mine. Though I cleaned and lubed the ground I also ran a wire to the main battery ground from the ecu ground, just to be sure.
 

·
Registered
Joined
·
1,611 Posts
I had a smilar issue on an old monster. It would turn over slowly even with a new battery but not start or would back fire but not start. I measured the voltage of the positive lead while trying to start the bike and found the voltage to drop below 9 volts. that voltage is too low for the ECU to work and deliver spark to the plugs. Upon investigation, I found the wiring from the positive lead of the battery had corroded. There was a junction just down from the positive terminal that was also corroded. What was happening was that there was a voltage drop through the corroded section due to the high resistance. I replaced the entire starting circuit with Motolectric cables, and the problem was fixed. The bike started immediately after pushing the starter button. Not sure if you have the same problem, but you may check the voltage of the positive lead while cranking the starter.
 

·
Registered
Joined
·
3,970 Posts
With the 59M and newer ECU's, they even make the starter solenoid drop out when the voltage goes below, maybe 10V. The older ST4 and ST2 had the 16M ECU that allowed your starter button to crank as low as the battery could go. But the newer ECUs (59M and 5AM) in the ST4s -- it's no longer the starter button alone -- the starter solenoid gets commanded by the ECU.

My weird running and eventually "no start" cranking attempts in Fall of 2017 turned out to be my ECU.
I chose to replace my 59M with a newer 5AM HW610. I almost fainted when I pressed the starter button, and my 996 ST4s fired to life on the HM1100 map that was in the 5AM that I had purchased on-line. It was wonderful to hear my engine start and run after months of trouble shooting. I since loaded an ST4s DP map into the 5AM, and am running really well. The newer map came out of a 2005 ST4a, and since the newer ST's have the newer dash, there are some things that aren't 100% correct:

GN: The 5AM ECU expects the IMMO "handshake" from the newer dash. GN is that it does not miss this, using the older dash/hardware. I believe it wants/acquires the stuff from the dash via CAN bus, which our older ones don't really have (maybe CAN just over to the IMMO).

BN: the barometer input is defaulted to sea level due to the above (baro unit now in the newer dash).

F it. She wheelies in 3rd gear now, which did not happen B4. So F it.
 
  • Like
Reactions: brutus72

·
Registered
Joined
·
7,368 Posts
I had a weird no start situation that turned out to be wires pulled partially out of the wire connector blocks just enough to make a bad connection inside. This was apparently done by zip ties placed too close to connectors at the factory, so I guess it could happen to anyone. My Monster would not crank, but the lights would come on. Go around the bike and push all the wires back into their connectors. It wouldn’t hurt to clean them either.
 
  • Like
Reactions: Stick

·
Registered
Joined
·
102 Posts
Discussion Starter · #13 ·
With the 59M and newer ECU's, they even make the starter solenoid drop out when the voltage goes below, maybe 10V. The older ST4 and ST2 had the 16M ECU that allowed your starter button to crank as low as the battery could go. But the newer ECUs (59M and 5AM) in the ST4s -- it's no longer the starter button alone -- the starter solenoid gets commanded by the ECU.

My weird running and eventually "no start" cranking attempts in Fall of 2017 turned out to be my ECU.
I chose to replace my 59M with a newer 5AM HW610. I almost fainted when I pressed the starter button, and my 996 ST4s fired to life on the HM1100 map that was in the 5AM that I had purchased on-line. It was wonderful to hear my engine start and run after months of trouble shooting. I since loaded an ST4s DP map into the 5AM, and am running really well. The newer map came out of a 2005 ST4a, and since the newer ST's have the newer dash, there are some things that aren't 100% correct:

GN: The 5AM ECU expects the IMMO "handshake" from the newer dash. GN is that it does not miss this, using the older dash/hardware. I believe it wants/acquires the stuff from the dash via CAN bus, which our older ones don't really have (maybe CAN just over to the IMMO).

BN: the barometer input is defaulted to sea level due to the above (baro unit now in the newer dash).

F it. She wheelies in 3rd gear now, which did not happen B4. So F it.
You were my inspiration for the new ECU. Weather has been too cold to get into it in my unheated garage in North Dakota. I've got the ECU, the programmer and the files you sent. Was just hoping to hear it "roar" before going through all that.

It's been under 2000 miles since valves were done, belt was done, plugs changed, etc. Bought from my cousin and he's a stickler for maintenance. It's only seen rain a couple of times and other than last winter, been stored in a temperature controlled space. I've seen no evidence of corrosion anywhere on the bike. Outside of lube fling around the chain, it looks showroom. Battery is new and been on the float charger all winter long.

Is the ECU on this thing under the tank or behind one of the side panels? I've done some searching but while I found a lot of cool info, nothing there.
 

·
Premium Member
Joined
·
5,676 Posts
Attached to the battery box, lower right pannel. You will need to get the right side off for full access, so naturally you need to get the headlight fairing off first, unless it’s an 04 or newer...
 

·
Registered
Joined
·
3,970 Posts
Also note the cables that get removed while unbolting the ECU. It's mounted to the plastic battery box. But it NEEDS to be grounded. Make sure that the one bolt with wire gets replaced WITH the gnd. wire.
Weird and sometimes bad things happen when this cable is forgotten.
 

·
Registered
Joined
·
116 Posts
I had very similar problems over the winter. Replacing the crank position sensor helped but didn't cure it.
What finally cinched it and got the bike running properly again was a cable kit. The oem starting circuit cables are marginal when new and get more resistant over time. Eventually, so much resistance builds up that the starter steals so much power that the ECU doesn't have enough.
 

·
Registered
Joined
·
102 Posts
Discussion Starter · #17 ·
She started. She was just being a bitch. An "above 40" kind of girl I guess.
 
1 - 17 of 17 Posts
Top