Why is my bike difficult to start?

[DucHead]

• 32,000 miles on my '05 S4R.
• Oil changed every 2500 miles -- never leaks or burns a drop
• Valves just checked -- all in spec except one opener and one closer (same valve)
• Throttle bodies synched, idle trim set
• Bike not run hard (one track day)
• $150 Odyssey battery
• Garage kept
• Ridden daily

It ran fine last week (after valve check and throttle body synch), but it sat one day (yesterday) and the temperatures are in the forties, and that mother make the beast with two backser will not start! 

The Odyssey turned the engine over 15-20 times before it started to show signs of weakening:  it sputtered a few times, but never started.  Dammit! 

If its 10°F outside, my 1200-cc Bandit starts and it has a battery that's over 4 years old!!

What's the deal?  At times like this, I wonder if it's worth the trouble of ownership.  It's made to be ridden and I ride it -- and I take good care of it, but when it won't start I feel like I can't trust it.   

[Howie]

Assuming you have fuel and spark, I would look at the IFI sensors that control cold start.  There is an air/pressure sensor behind the headlight and a cylinder head temperature sensor on the horizontal cylinder.  Unfortunately, I don't know the specs, but the easy way to check is with the factory scan tool or technoresearch software.  If you are near speeddog (Valley Ducati Service) give him a call

[DucHead]

Thanks Howie.

I'm not near Speeddog, but next time I have the bike at the shop, I'll ask them to check.

It did start today.  I re-charged the battery and it started on the second try.

[ducpainter]

I always wonder at the change of season how fuel quality affects things.

It doesn't take much water to make an engine refuse to start.

A small amount of dry-gas won't hurt and will eliminate one possibility.

[DucHead]

I always wonder at the change of season how fuel quality affects things.

It doesn't take much water to make an engine refuse to start.

A small amount of dry-gas won't hurt and will eliminate one possibility.

Thanks DP, I'll give that a try too. 

[bazz20]

Thanks Howie.

I'm not near Speeddog, but next time I have the bike at the shop, I'll ask them to check.

It did start today.  I re-charged the battery and it started on the second try.

check your battery voltage when it wont start then check when its fully charged , most efi bikes wont start if voltage falls below a certain voltage 

[krista]

And I always recommend replacing the battery and starter cables with 4 or 6 ga stranded cable from Napa, etc.

[DucHead]

And I always recommend replacing the battery and starter cables with 4 or 6 ga stranded cable from Napa, etc.

Starter cable is brand new 6 gauge stranded.  Battery cables are OEM and battery is a brand new Odyssey PC310 from Motowheels.

[Howie]

I always wonder at the change of season how fuel quality affects things.

It doesn't take much water to make an engine refuse to start.

A small amount of dry-gas won't hurt and will eliminate one possibility.

Seasonal change can have an effect, different volatility between summer and winter mix.  Yeah, water is a possibility too.  Be conservative with the dry gas if you live in an area that uses E10 though, since there is already alcohol in your fuel.

[bigiain]

battery is a brand new Odyssey PC310 from Motowheels.

"brand new" as in "possibly never fully charged"?

If leaving it on the charger overnight "fixed" it, it was almost certainly the battery, which means it's either faulty (not a complete impossibility, even for a good brand name battery), or it just needed charging...

big

[DucHead]

"brand new" as in "possibly never fully charged"?

If leaving it on the charger overnight "fixed" it, it was almost certainly the battery, which means it's either faulty (not a complete impossibility, even for a good brand name battery), or it just needed charging...

big

It's about 3 weeks old and received a full charge when it arrived.

[Jarvicious]

I don't think I've ever had to turn the engine over 15-20 times in a row to get it started, but wouldn't that tax any battery??  Seeing as how you have a new battery with 3 weeks of daily use out of it, it sounds like it's just a gas-meets-cold issue and not a problem with the battery.  Was it warmer when you finally got the bike to start?  At 32k you may need to check your fuel filter too, if you haven't already.  Even if you can get the engine to turn over, it's not gonna fire up without gas running to it.  Does anyone know if cold temps could exacerbate flow issues in an already clogged filter?  I guess it's all a moot, as you got it running 

[Capo]

Does anyone know if cold temps could exacerbate flow issues in an already clogged filter?  I guess it's all a moot, as you got it running 

No, the changes in temperatures have an insignificant affect on viscosity.

However, as has been stated fuel is a prerequisite, and this will include the fuel delivery system not just the ECU that controls it.
It could be a fuel pump problem, were the wires/connector disturbed when the new battery was installed?

[Speeddog]

My S4 has been difficult to start when temps are in the 30's (degF).

Never really found out why, it's been quite a while since I've been faced with temps that low.

[DucHead]

... it's been quite a while since I've been faced with temps that low.

Bastid!   

...were the wires/connector disturbed when the new battery was installed?

No.

...At 32k you may need to check your fuel filter too, if you haven't already. 

This sounds like a great idea.