Fuel injectors shut off on decel.

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Klutch556

Registered
Does anyone know if the 2019 busa shuts the injectors off completely on decel?
I was watching This and he mentions at the 4 min mark that a lot of bikes do this and you can’t change it with a power commander.

I ask because what he described is exactly what I experience on my bike. When you let off the gas, it’s nearly impossible to roll back on smoothly. It’s not a jerk like it got too much gas too quick but a buck like the power comes back abruptly.

Is this something that can be flashed over on the ecu?

Thanks in advance <3
 
Klutch556 said:
Does anyone know if the 2019 busa shuts the injectors off completely on decel?
I was watching This and he mentions at the 4 min mark that a lot of bikes do this and you can’t change it with a power commander.

I ask because what he described is exactly what I experience on my bike. When you let off the gas, it’s nearly impossible to roll back on smoothly. It’s not a jerk like it got too much gas too quick but a buck like the power comes back abruptly.

Is this something that can be flashed over on the ecu?

Thanks in advance <3
Click to expand...

My 2018 Kawasaki Z900RS acts exactly this way. Upon decel it feels like you’ve downshifted. Trying to maintain a steady speed thru the twisties or an easy roll on roll off in the lower gears is just about impossible. Holding a steady speed in the lower gears on a rough road also causes the throttle to close and the fuel shutoff and then a big wham when trying to roll back on the gas, even a lil bit. I’ve adjusted the cables as I did on my Busa and it helped a bit. Everyone on the Z forum mentions this and a reflash of the ecu does cure the problem. Cost is around $300. I spoke with Frank at Powerhouse about this and he mentioned that nearly all later model bikes have this problem to some degree. Has something to do with meeting EU emissions requirements. I am getting better at finessing the on/off throttle input but I’m also thinking about the flash. I might have the thermostat fan temp lowered as well. Try adjusting the cable free play and send Frank a note if it doesn’t help enough.
 
Klutch556 said:
Does anyone know if the 2019 busa shuts the injectors off completely on decel?
I was watching This and he mentions at the 4 min mark that a lot of bikes do this and you can’t change it with a power commander.

I ask because what he described is exactly what I experience on my bike. When you let off the gas, it’s nearly impossible to roll back on smoothly. It’s not a jerk like it got too much gas too quick but a buck like the power comes back abruptly.

Is this something that can be flashed over on the ecu?

Thanks in advance <3
Click to expand...

I dont know if they shut off completely but if you decel. and go back on the gas- it should not be UNsmooth. (abrupt)
Flashed or not flashed!
 
Last edited:
This is normal on the gen 2. It’s call DFCO or deceptive fuel cut off, and it’s cant be shut off.

This is in place to eliminate popping at higher rpm, high vacuum, at closed throttle on decel. The jerkiness is usually due to being too lean in the area where the injectors turn back on. This isn’t the easiest issue to address while tuning with a power commander but can be done.
 
Injector shut off on decel can be effectively eliminated through the ecu. We do it all the time, and the road racers love it. The first bike was a BMW S1000RR at Thunderhill Raceway. We sent an experienced rider out with a stock ecu for a 1/2 dozen laps, and upon returning to pit, we flashed and derestricted his ecu. Send him back out, while a group of us took bets on how much quicker his lap times would be - I thought about a second quicker. I was wrong. The rider went 2 - 3 seconds quicker on every lap. This blew us away. When questioned, this rider said that although the throttle response and power was better because of the flash, eliminating the injector shutoff on decel make the chassis more "solid" . . . chopping throttle into the turn and rolling it back on there was no wiggle in the chassis anymore. He felt more confident and went into every turn harder, through the turn quicker, and as a result, came out faster. We did this with Ecu Unleashed.
 
Hauie said:
Weird. I don’t feel like with my 2018, maybe ask the dealer?
Click to expand...
Dealer said “you’re just a new rider and haven’t learned the throttle”
Boosted Cycle Perf said:
This is normal on the gen 2. It’s call DFCO or deceptive fuel cut off, and it’s cant be shut off.

This is in place to eliminate popping at higher rpm, high vacuum, at closed throttle on decel. The jerkiness is usually due to being too lean in the area where the injectors turn back on. This isn’t the easiest issue to address while tuning with a power commander but can be done.
Click to expand...

I’m not running a PC. Less moving parts and such lol.
Honestly, I’m just glad I’m not crazy or inept and it’s a real thing. I’m having the ecu flashed when I install this exhaust. So I’ll wait till then to see where everything settles in.
I appreciate the info though, makes addressing the issue a lot easier than trying to explain it to someone haha
 
Some of this issue was remedied with a couple adjustments that needed to be made.
First my throttle free play, found the adjustment knob on the cable and snugged it up quite a bit. From about 9/16” down to 1/8”
Then I tightened up the chain which had 2 1/8” play down to 1 1/16”

These two adjustments made a big difference on the issue. It’s still very noticeable but I feel much more... in control I guess is the best way to say it. Being a new rider, it’s kind of amazing how one seemingly unimportant issue can affect your overall confidence when riding.
 
Klutch556 said:
Dealer said “you’re just a new rider and haven’t learned the throttle”


I’m not running a PC. Less moving parts and such lol.
Honestly, I’m just glad I’m not crazy or inept and it’s a real thing. I’m having the ecu flashed when I install this exhaust. So I’ll wait till then to see where everything settles in.
I appreciate the info though, makes addressing the issue a lot easier than trying to explain it to someone haha
Click to expand...


Yeah, I sent my ecu off to frank at powerhouse and he flashed it and unleashed it. Might be why I never felt it since I flashed my bike at 150 miles.
 
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