03 xb9 missfire at full throttle

[apsolus]

I've been enjoying my bike on the track a bit lately and its been running fine but no long at wot. this all seemed to happen tonight while on a long group ride on the highway. couldn't tell while i was in the group due to all the noise but on my way home i tried a full throttle accel up the gears and once i get to full thottle the bike starts to misfire and won't rev past 6k in all gears. bike still starts and runs perfectly at anything less than full throttle. nothing as far as google for an xb missfiring like mine is but i did see some stuff on the x1 but didn't help much. ideas?

like i said 3/4 and below no issues at all and a clean rev up to redline but once i hammer it it falls flat. ill be checking the plugs and wires soon but all that was replaced not to long ago while i was chasing a bad idle long ago that was just a pinched wire. my bike was a lightning that was turned into a fireboat

 

[thrstrmech]

any codes? may have either a fuel / electrical issue or both. do you have a service manual? follow the trouble shooting tree in chapter 4, under Misfire. check the fuel pressure, battery, battery connections, old/new battery? check over the basics for proper installation/connections/condition...plug wires, etc.

 

[apsolus]

i do have a manual, and its the factory one so its very helpful as far as the diagnostics. ill look into it tomorrow. ill need to hurry if I'm going to make it to the track this monday.

 

[apsolus]

battery is pretty new, like a few months but ill def check the batt and charging system tomorrow during my diagnostics for sure. bike still starts and idles perfectly and runs perfectly so long as i don't hammer it. its like an on off switch somewhere in between 3/4 and wot is there the problem starts, so I'm gonna check into the sensors too.

 

[apsolus]

took it out this morn and found it will run at full throttle up to redline until warmed up, once warmed up blaaahhh. but only at full throttle, if i give it around 80 % it revs out fine. anyone ever had a GM 4 speed autotrans like the 700r4 not want to upshift at full throttle out of second unless you lift off the gas? my bike kinda acts the same way. when I'm accelerating at wot if i back it off the power comes back on and it accels.

 

[Chicknstripn]

Check your service manual for a trouble shooting procedure for the engine temp sensor. A failing temp sensor could cause the issue you're talking about. Especially if the bike is only having issues once it's warmed up.
Could also be an issue with your O2 sensor. Have you checked what your AFR is before and after a ride?
It's common to have the wires on those two sensors wear through and short out.
Check em out just to be on the safe side.
I know you don't want to hear this and I almost don't want to say it but the TPS could also be at fault. You getting a good signal from it? And have you tried to reset it once you've warmed the bike up?
Just some ideas man. I hope it helps and doesn't just add fuel to the fire of confusion.
Like Crash said earlier. You'll have to systematically check EVERYTHING.
The service manual is your friend.
Good luck

 

[apsolus]

word. my sister suddenly needs a ride out west and I'm off tomorrow morning. ill get with you guys later

 

[apsolus]

i found that the engine temp sensor wiring was indeed rubbing on the engine in two spots and the frame in another, but close examination shows no exposed wiring yet. i tested battery output and its fine 13.6 idle, checked fuel pressure engine running as in manual and its showing 50 psi. the negative battery terminal was slightly loose and I'm able to move the wiring thats attached to it so i torqued it back down. o2 sensor wiring was in good shape. I'm going to reroute the engine temp sensor wiring put it back together and retest. any other ideas? forgot to mention, no codes were stored.

 

[apsolus]

also i have an 03 model year bike, which is bad news for me because i can't use ecmspy right? nor can i do the tps reset right? how would i test the o2 sensor without the ecmspy?

 

[thrstrmech]

who told you that, I use ecmspy on my '03 and works just fine...

 

[apsolus]

its the race ecm my bike has is why i can't use ecmspy. not that its an 03 my bad. do i need a stock ecm before i can use ecmspy?

 

[thrstrmech]

I have the race kit installed and ecmspy works just fine

 

[apsolus]

guess i was wrong on all accounts! not unusual. i bought the cable and added the software to my laptop awhile back and had complications i remember only seeing a blank screen on my laptop with everything plugged in.

anyway i did what i said i was going to do and rerouted the ET sensor wiring put it together and tightened down the neg batt terminal and its still acted up. figured digital technician was the next best step and the 105 price for diag isn't out of my budget. you know what, i found a good harley dealership thats really close to my house and they have corrected a few other issues with my Buell.

Im a dealership level technician myself and i know the difference the right scanner can make. they said they would be able to take a look at it in a few days so i dropped it off and will await the diagnosis. ill keep everyone updated.

 

[apsolus]

i need to get one of those, "wrench, ride, repeat" stickers for my bike haha

 

[UMDterp13]

Tps reset? I had one doing this and that cleared it.

It's a tps issue or air/fuel issue. (Pump, broken intake, injectors)


Idk, y'all somehow have a billion different issues that aren't normal haha

 

[apsolus]

ok, that would make me happy if thats all it needed so i wouldn't need any new parts. although i have noticed my idle adjustment cable is badly chewed up near the coil where it contacts the cylinder head going into the throttle body. i sure hope the cable still works and they don't need to order me a new one! cause that would probably take 5 years to come in right? lol how come the tps just decides one day its going to be out of adjustment? i checked and its installed properly and looks like its been in the same spot for a very long time.

 

[thrstrmech]

that cable is part of the throttle body assembly and isn't sold as an individual piece. you would have to find one on ebay or from someone on the forum.

 

[Chicknstripn]

http://americansportbike.com/newdir/index.php?app=ecom&ns=prodshow&ref=17558

I think this is the part you need. If you decide to replace it. Mine did the same thing and ASB got one out to me in about 3days. I'm on the easy coast and that was faster than my dealer could get one.

 

[apsolus]

just ordered it myself, thank you sir.

hopefully i can perhaps get this part to the dealer and have them install it while they have the bike torn down. I'm really looking forward to track time! but i am going to have to do some major work soon. my rear base gasket is leaking. i really wasn't going to mess with it, just kinda clean it up real good from time to time but once i found out my swing arm bearing failed due to the trail of oil that hits it from the engine leak i gotta fix that ****, I'm lazy but not that lazy! looking forward to attempting the engine tilt method. do you have to remove the front tire to do the engine tilt method or just the motor mount and bracket?

should i do the frame lift instead? I'm very capable in tight places. worked on many a diesel power stroke van, ambulance, airport shuttle ect. so if the issue with the engine tilt method is room to work, don't worry bout that girly stuff lol

 

[Chicknstripn]

Better not to remove the front tire. There's a sticky or whatever you call it in the "do it yourself mods" section that I believe is all about engine rotation. It's pretty easy.
Did you say you had a service manual? If you don't just google buell xb engine rotation and study up. I used the manual the first couple times I rotated my engine and it's almost fool proof using the book. I can do it by memory now.
BTW I have some base gaskets that I never used during a rebuild. They're for an 07 xb12r but I'm pretty sure they will fit your 9. Look into it. If they do fit, You have em if you want. Free. Just PM me your address and they're yours.
I have too many little parts collecting dust. Does me no good to hold on to the stuff so you'll probably see more posts where I offer up such little parts for free to those members that need em.
LMK