Sputtering Once Heated Up (Resets on Shutdown)

[sopenco]

Hey, all,

I've tried to read all the posts about sputtering, losing power, but I'm still stumped.

I've got a 2009 that starts GREAT and runs GREAT. Then, after about 20 minutes worth of riding (highway or city makes no difference) the problem starts.

In first and second gears, the engine sputters so bad I have to squeeze the clutch and rev the engine before reengaging the clutch to get going. Once it's in motion and toward the higher end of first, it seems to do a bit better. Second gear, same thing. Not quite as bad, but still struggling. Third gear - still present but hardly noticeable. From there, I'm usually okay as long as I don't gas it real hard.

So, I shut it down and start it back up. Once I do - it's back to great (but for only another 5 minutes at best and then it'll start acting up again.

And the problem is consistent. There's never a ride where it doesn't act up at the same time. It's not worse on some days and better on others.

So far, I've changed the spark plugs (which needed to be done anyway) and I relocated my intake air temp sensor (which stays nice and cool now, but doesn't solve the problem unfortunately). While I had the IAT sensor off, I also tested it and it's working fine.

Any ideas?

 

[busa2001]

Hey, all,

I've tried to read all the posts about sputtering, losing power, but I'm still stumped.

I've got a 2009 that starts GREAT and runs GREAT. Then, after about 20 minutes worth of riding (highway or city makes no difference) the problem starts.

In first and second gears, the engine sputters so bad I have to squeeze the clutch and rev the engine before reengaging the clutch to get going. Once it's in motion and toward the higher end of first, it seems to do a bit better. Second gear, same thing. Not quite as bad, but still struggling. Third gear - still present but hardly noticeable. From there, I'm usually okay as long as I don't gas it real hard.

So, I shut it down and start it back up. Once I do - it's back to great (but for only another 5 minutes at best and then it'll start acting up again.

And the problem is consistent. There's never a ride where it doesn't act up at the same time. It's not worse on some days and better on others.

So far, I've changed the spark plugs (which needed to be done anyway) and I relocated my intake air temp sensor (which stays nice and cool now, but doesn't solve the problem unfortunately). While I had the IAT sensor off, I also tested it and it's working fine.

Any ideas?

what's the fuel pressure, did you check the fuel filter? also make sure your TPS is adjusted properly.

 

[Sandow]

Hey, all,

I've tried to read all the posts about sputtering, losing power, but I'm still stumped.

I've got a 2009 that starts GREAT and runs GREAT. Then, after about 20 minutes worth of riding (highway or city makes no difference) the problem starts.

In first and second gears, the engine sputters so bad I have to squeeze the clutch and rev the engine before reengaging the clutch to get going. Once it's in motion and toward the higher end of first, it seems to do a bit better. Second gear, same thing. Not quite as bad, but still struggling. Third gear - still present but hardly noticeable. From there, I'm usually okay as long as I don't gas it real hard.

So, I shut it down and start it back up. Once I do - it's back to great (but for only another 5 minutes at best and then it'll start acting up again.

And the problem is consistent. There's never a ride where it doesn't act up at the same time. It's not worse on some days and better on others.

So far, I've changed the spark plugs (which needed to be done anyway) and I relocated my intake air temp sensor (which stays nice and cool now, but doesn't solve the problem unfortunately). While I had the IAT sensor off, I also tested it and it's working fine.

Any ideas?

Cant say anything about your issue, but I am sure the guys who are experts (@c10 garage video maybe) will ask for more info...
Mileage, any previous issues, any recent changes...etc etc...

 

[Tached1300]

Could be TPS sensor, wouldn't hurt to verify fuel pressure either. Has the bike sat for quite some time? Another low cost trial would be to put some seafoam in the tank and run it out to see if it clears up, something could be clogged within the fuel system, filter, injectors etc...

Also check to see if the problem exists w/o a load on the engine

I haven't really studied the fuel injection system on the hayabusa or tuned them, but in general there could be something going on with it in open vs closed loop if they are setup that way. But I'd start with the simple stuff and like mentioned verify that your TPS is at the correct value.

 

[Bumblebee]

A little more info is required as mentioned above...

 

[c10]

Millage, mods , owners , use , services??

 

[ottafish]

Pictures?

 

[sopenco]

what's the fuel pressure, did you check the fuel filter? also make sure your TPS is adjusted properly.

I haven't tested the fuel pressure. The filter is only a couple of months old. I haven't checked the TPS, but I doubt it would be the problem anyway. Correct me if I'm wrong, but would the adjustment be something that makes it stop working after 20 minutes and then work again for five once I shut down and then start back up? It just doesn't seem to fit the profile.


The more I think about it, the fuel pump could probably be heating up and creating resistance in the coil / brushes. And that few seconds worth of shutdown could also be cooling the coil / brushes enough to make it normal for a couple more minutes. I've got a DC clamp I can use to check current on that guy at the beginning and end of a ride. That should tell me if that's what's going on...

 

[sopenco]

Could be TPS sensor, wouldn't hurt to verify fuel pressure either. Has the bike sat for quite some time? Another low cost trial would be to put some seafoam in the tank and run it out to see if it clears up, something could be clogged within the fuel system, filter, injectors etc...

Also check to see if the problem exists w/o a load on the engine

I haven't really studied the fuel injection system on the hayabusa or tuned them, but in general there could be something going on with it in open vs closed loop if they are setup that way. But I'd start with the simple stuff and like mentioned verify that your TPS is at the correct value.

The bike hasn't been sitting for anything more than a day or two without getting used and abused. I'm not sure why a clogged fuel system would only act up after 20 minutes of riding and then get better after a quick restart, so I'm doubtful that's it. Plus I've run an injector cleaner through it, the filter's new and this problem has survived about 4 or 5 tanks of gas.

 

[sopenco]

Millage, mods , owners , use , services??

Less than 8k miles, stock where it counts, irrelevant, recreational street riding, nothing beyond basic maintenance.

 

[sopenco]

Pictures?

If it'll help you identify the problem, let me know which systems / parts you want pictures of, and I'll go out and shoot a couple.

 

[Tached1300]

The bike hasn't been sitting for anything more than a day or two without getting used and abused. I'm not sure why a clogged fuel system would only act up after 20 minutes of riding and then get better after a quick restart, so I'm doubtful that's it. Plus I've run an injector cleaner through it, the filter's new and this problem has survived about 4 or 5 tanks of gas.

just trying to help rule out the simple stuff, hope you get to the root of the issue

 

[shade]

Yup fueling.
As another said check fuel filter then onto the fuel pump. Bet its dying

 

[Berlin Germany]

(...) While I had the IAT sensor off, I also tested it and it's working fine.

no real help, sorry
but a kind of idea what is partly going on
when you disconnect the IAT.

then the ECU switches into a "special mode" and assumes an intake air temperature of something around 23 °C / 73 °F.
the ignition timing and injection quantity are then controlled with this assumed value.

and what does this exactly! mean :
" it's working fine "
e.g. "over the entire rpm range" ?

hey sopenco
MY idea is :

sit down , remember 100% what you did to any screw/nut, wire, harness, plug and so on
and pls don´t forget to say wich "kind of use" the problems started

write this all 100% exactly down and post this.

then a remote diagnosis - perhaps - may help further.

 

[sopenco]

just trying to help rule out the simple stuff, hope you get to the root of the issue

I hope I didn't come off as sounding ungrateful. I do appreciate you (and everybody else) brainstorming with me on this!!

 

[c10]

It is easy to kink the Gen 2 fuel line after raising the fuel tank , and lowering it back into place . Have a look there .

 

[sopenco]

no real help, sorry
but a kind of idea what is partly going on

I'll take what I can get.

when you disconnect the IAT.

then the ECU switches into a "special mode" and assumes an intake air temperature of something around 23 °C / 73 °F.
the ignition timing and injection quantity are then controlled with this assumed value.

Useful info - thanks for sharing!

and what does this exactly! mean :
" it's working fine "
e.g. "over the entire rpm range" ?

Let me try to be more verbose: the tested resistance of the IAT sensor decreases along a predictable, logarithmic decay curve as the temperature of the sensor increases throughout the domain of anticipated working values.

hey sopenco
MY idea is :

sit down , remember 100% what you did to any screw/nut, wire, harness, plug and so on
and pls don´t forget to say wich "kind of use" the problems started

write this all 100% exactly down and post this.

then a remote diagnosis - perhaps - may help further.

That sounds like quite a challenging memory exercise. But at my age, it's not likely one I'd undertake voluntarily.

 

[sopenco]

It is easy to kink the Gen 2 fuel line after raising the fuel tank , and lowering it back into place . Have a look there .

I'm not sure the kink would allow me 20 minutes of smooth running before it acts up, but I will keep an eye on that line when closing back up from now on, I didn't know this was a thing. Thanks for mentioning it!

 

[Berlin Germany]

@sopenco

you have the entire suzuki manual?
sorry for that fool´s question,
but if not look for one - for these probs it is a MUST HAVE.
there are dozens of hints all alone to possible IAT´s misfunktions
and to all others for sure too.

it you have no manual
use the search function here - some 2 or 3 weeks ago we had a perfect link to one. ;-)

 

[sopenco]

@sopenco

you have the entire suzuki manual?
sorry for that fool´s question,
but if not look for one - for these probs it is a MUST HAVE.
there are dozens of hints all alone to possible IAT´s misfunktions
and to all others for sure too.

it you have no manual
use the search function here - some 2 or 3 weeks ago we had a perfect link to one. ;-)

I'm supposed to be getting one emailed to me at any time. Thanks for the suggestion! I have 'a Suzuki manual' but it's not complete and it's actually for a different Gen2 model. The one that's coming is the exact right one. Hopefully it'll help.