Argg, more S4 electrical problems… help :(

[mintyhit]

Right, this is really getting on my nerves now. First I had the regulator\rectifier problem… I replaced it and fixed the warning light\charging problem… then I had starting problems so I fitted a new battery and a new earth strap, this seemed to solve that.

Now I have a bl00dy idling problem. It seemed to start when I went out for a good solid days riding last weekend. I got back the bike now refuses to maintain a stable idle as soon as the temperature peaks 160F. Today it stalled on the way to work and wouldn’t start again until I bumped it down a hill.

It was the same starting problem as before when I had the battery\regulator problem. The starter turns the engine a semi turn and struggled and clicks like there is not enough power… wtf?

So anyway, the idle problem, I took a short 10second video:

http://www.youtube.com/watch?v=dhtzW4xJjdI&sns=em

Can anyone suggest anything I could check that would cause this? As it seems to run fine with cold I suspect perhaps a fueling issue perhaps?

Thanks guys.
J

[slipperyweeguy]

Are you treating the misfire and non-start symptoms as two separate problems? I think I would.
The content of the video looks and sounds very familiar. Have you read through the thread titled "S4 cutting out "? When the engine is hot and revs are erratic at idle, just unplug the front cylinder's coil's white connector. If the idle speed seems stable with it disconnected, it indicates a weak or mis-timed spark at the front cylinder. Reconnect the front coil, and idle becomes erratic again? Repeat the test on the rear cylinder. If you unplug a good cylinder and let a misfiring one try to sustain idle, it will sound much worse and possibly stop quite quickly. Since failing coils resistance commonly increases with temperature, the hotter they get, the worse they work.
As for the randomly occurring charging /starting issues, I re-read your original posts from weeks ago, and it seems the only thing you have not factored in is the nightmare of an internally broken wire...
I'm heading home tomorrow to try to work out if I need a new battery or regulator/rectifier.

[chris yeatman]

could it be a coolant temp sensor telling ecu to put in more or less fuel in?
mite be worth getting it on a computer and reading the ecu.

[Dukedesmo]

Does it pop/backfire at idle? I have a 916 which is basically the same engine. Most running problems can be completely cured by doing a full setup: TPS, throttle balance and CO settting - make sure the CO is not too low.

[Capo]

mite be worth getting it on a computer and reading the ecu.

Way to go (The ONLY way).

Free software available here http://www.ducati-upnorth.com/forum/showthread.php?t=12961&highlight=free+software

[Gordon H]

computers/ecu/coolant sensor?? all sounds a bit too bloody complicated......

[Capo]

It's called technology, we have no option but to embrace it.

[mintyhit]

Once again, thanks for all the helpful advice… I unplugged the front cylinder and the idle stabilised.

I took the coil out, cleaned up the connections plugged it back and it is steady as a rock again… great.

Now all I need to do is solve this cursed starting issue and I’ll be happy.

… it actually completely failed on me this morning on the 4degree city coldness. I swapped over the battery for a fully charged and using a bit of thick wire connected the starter straight to the positive on the battery.

The result: Well it turned over as apposed to just clicking but very very slowly… in fact I didn’t think it would start at all until it barked into life.

I am starting to think it must be my starter motor now… I’ve put a new earth strap on, new battery, direct connection to the battery and still when the weather is cold it barely starts.

Anyway have any other ideas or should I start saving for a new starter? 

Cheers
James

[Scotty]

starter motors either work or they dont

the S4 is a bit of a pig to start in the cold

so reduce the load it takes as far as possibly

neutral, clutch in, lights off

when ive not enough juice to quite turn the motor over , i often try and bump start and press the starter button as i dump the clutch

[slipperyweeguy]

Since you have proved that the starter motor works when it is hot-wired, and did not work when going through the loom... wires, switch?
By coincidence, on the same day (zero degrees, ice, roads salted here), I was checking to see why my own S4 had recently popped a fuse, had started after cranking very slowly, then been ok, then cranked slowly etc.
I took a photo of the wires at the back of the fuse box. They had been chafing against the bracket, providing an intermittent, poor short/earth. Just enough to cause trouble.
Fixed the wires, and the bike spins over brilliantly. Your experience may vary.
http://i1085.photobucket.com/albums/j430/paintguru/ducati/fusebox02.jpg
http://i1085.photobucket.com/albums/j430/paintguru/ducati/fusebox01.jpg

[analogue_rogue]

starter motors either work or they dont

the S4 is a bit of a pig to start in the cold

so reduce the load it takes as far as possibly

neutral, clutch in, lights off

when ive not enough juice to quite turn the motor over , i often try and bump start and press the starter button as i dump the clutch

not true.. starter motors can develop bad connections and/or poor windings and start to turn slowly.This can be simulated by constantly cranking the starter for minutes until it starts to slow down as the breakdown occurs. Also due to the build up of back emf generated by the coils inherent inductance over time as the build up of heat can alter the resonant frequency for the circuit..... </geek talk>

[Dookbob]

Once again, thanks for all the helpful advice… I unplugged the front cylinder and the idle stabilised.

I took the coil out, cleaned up the connections plugged it back and it is steady as a rock again… great.

Now all I need to do is solve this cursed starting issue and I’ll be happy.

… it actually completely failed on me this morning on the 4degree city coldness. I swapped over the battery for a fully charged and using a bit of thick wire connected the starter straight to the positive on the battery.

The result: Well it turned over as apposed to just clicking but very very slowly… in fact I didn’t think it would start at all until it barked into life.

I am starting to think it must be my starter motor now… I’ve put a new earth strap on, new battery, direct connection to the battery and still when the weather is cold it barely starts.

Anyway have any other ideas or should I start saving for a new starter? 

Cheers
James

Was the wire you used for the hotwire thick enough, it,s got to be at least as thick as the standard battery to solonoid cable, preferably a bit thicker. The other thing that springs to mind is that you never get as good a connection holding a wire against a terminal by hand, as you do when it is bolted up.

[Hubcaps]

Have you had a look at the idle Co2 settings? In my opinion it looks like thats out and also the idle speed is far too low. Should be about 1200-1300 rpm.

[threewheelsonly]

Just posted a remedy to a cutting out fault with my S4, some times mine woud wind and cut out almost instantly 3 or four times while holding the start button, this was besides the engine stopping at any time once running.
The run/stop switch had corrosion on the contacts and the slightest movement/ vibration would break the contact and the engine would stop or not even wind over with the starter.