I'm still confused about the fuel cut on decel issue

[michigan400]

17 hours ago, D.A. said:

@michigan400: Yep, I mailed the ECU to 2WDW last week, they’ve received it and said they’ll flash and ship back to me today. But I nonetheless appreciate your input!

Incidentally, before mailing I did unplug, spray-clean and reconnect the ECU a couple of times, test riding the bike after each connection. There was no discernible change in the bike’s behavior. And to answer your other question, the bike has had jerky fueling since the day I bought it. I did buy it used, though, but the original owner made no performance-related alterations to it. 

I don’t think there’s anything extraordinary or atypical about my bike’s twitchy throttle. Based on what I’ve read on this forum, it seems a lot of other owners have experienced the exact same phenomenon. My confusion — and my impetus for starting this thread — was about how to best solve the problem. 

Many people on here maintain the issue is primarily a result of fuel being cut on deceleration but that answer never seemed logical to me because even though the twitchiness does occur when you roll off the throttle then get back on the gas again, it also occurs when you first start up the bike, roll on the gas, let out the clutch and reach about 2300 rpm. Meaning, it happens before the bike has ever decelerated. And if the jerkiness can occur before you decelerate, it cannot plausibly be caused by fuel being cut on deceleration.

I also find that answer frustrating because I like my stock FZ’s engine braking just the way it is and prefer not to have it diminish.

I’ve always known it was a fueling issue of some sort but have been hoping to determine EXACTLY where the issue originates so I can troubleshoot it effectively — not just come up with a workaround. Unfortunately the best answer I’ve been able to find is that the bike is twitchy at small throttle openings because of the overlapping effects of lean fuel mapping and fuel-cut-on-decel. I’m not entirely satisfied with that answer but unless I buy a Dyno and a Flash Tune harness and develop the skills to use them, I’m not sure I’ll ever get a better answer. 

So, I decided to stop resisting and go with the flow by having the ECU reflashed. If this approach successfully eliminates the issue, I can stop obsessing over it. If not, the search will continue!

Mine is 100% stock and never did anything like that. It's a little twitchy on throttle response but not like you describe.

One other little dumb thing to check would be your intake and air filter. Make sure snorkel isn't partially blocked or the air filter isn't so dirty it can't breathe properly. 

 

 

[D.A.]

2 hours ago, seven said:

They quoted me $150 for just the tune.

Wow. That seems like a very smart option!

Also, I notice the discount code (covid19) gets you $65 off the normal prices of FTECU kits on 2WDW’s website, dropping the FZ07/MT07 bench flashing kit price from $400 down to $335 and the bike-side kit from $340 to $275.

$275 for the bike-side flashing kit plus $150 for the tune file sounds like a very versatile and economical way to go.

Wouldn’t do me a lot of good, though, since my computers are all Macs and you apparently need a PC to run Flash Tune’s software. 

[michigan400]

Have you got your ECU back yet?? Just curious if that solved your issue or not.

[D.A.]

Hey @michigan400: Yep, I did receive my newly flashed ECU from 2WDW and will post my results / impressions soon. First, though, I have a few maintenance tasks to take care of. I installed a new air filter today and am now in the middle of changing the spark plugs. When that's finished I'll re-sync the throttle bodies and test ride the bike again. I need to make sure none of these items are skewing the results of the flash.

[michigan400]

Just curious,,, and a little bored. Figured I'd ask! LOL!!

 

Hope it works for you.

[1down5up]

13 hours ago, D.A. said:

Hey @michigan400: Yep, I did receive my newly flashed ECU from 2WDW and will post my results / impressions soon. First, though, I have a few maintenance tasks to take care of. I installed a new air filter today and am now in the middle of changing the spark plugs. When that's finished I'll re-sync the throttle bodies and test ride the bike again. I need to make sure none of these items are skewing the results of the flash.

If you go and change everything at once, you're not going to be able to isolate any of the variables lol

[D.A.]

14 hours ago, 1down5up said:

If you go and change everything at once, you're not going to be able to isolate any of the variables lol

So true!

Perhaps I should have been more specific: I changed the air filter and spark plugs. Neither was really necessary since the bike only has 8000 miles on it and the original filter and plugs were fine. But I was in there so I swapped them out nonetheless. Then I rode the bike for a couple of hours. There was no noticeable difference between the old filter/old spark plugs vs. new filter/new spark plugs but at least I now know for certain my issues are not filter- or plug-related.

On Thursday I will re-sync the throttle bodies and test ride the bike. Then post my report.

[bartman5impson]

On 9/1/2020 at 11:40 PM, D.A. said:

So true!

Perhaps I should have been more specific: I changed the air filter and spark plugs. Neither was really necessary since the bike only has 8000 miles on it and the original filter and plugs were fine. But I was in there so I swapped them out nonetheless. Then I rode the bike for a couple of hours. There was no noticeable difference between the old filter/old spark plugs vs. new filter/new spark plugs but at least I now know for certain my issues are not filter- or plug-related.

On Thursday I will re-sync the throttle bodies and test ride the bike. Then post my report.

So how was the ECU flash?