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Buell Forum » XBoard » Buell XBoard Archives » Archive through August 12, 2008 » ECM Spy "Fuel cutoff in Decl" feature??? « Previous Next »

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Mnbueller
Posted on Monday, August 04, 2008 - 08:17 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

I just upgraded my ecm spy to the new 1.12.1 version and I noticed this feature. Has anyone done this or tried it? What the effects? Do you recomended it?

http://i38.photobucket.com/albums/e106/jbicknese/E CMspy_ECMconfig.jpg
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Swordsman
Posted on Monday, August 04, 2008 - 08:40 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Funny you should mention that... I've been wondering the same thing, and been meaning to post this same question.

I would imagine that it could save gas, and would probably be the end of popping during deceleration.

~SM
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Mnbueller
Posted on Monday, August 04, 2008 - 09:48 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Swordsman - yeah, that is exactly what I am hoping it will do. I think even if I haven't gotten a response from someone who has tried it, I will change it my bike and see how it works on my ride home from work today.
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Xl1200r
Posted on Monday, August 04, 2008 - 10:29 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Are we certain that the bikes don't do this already?

I know that the EFI system on my car turns the fuel-injectors off anytime the ther throttle is closed and the RPMS are between something like 2500 and 6000.
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Mnbueller
Posted on Monday, August 04, 2008 - 10:35 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

XL1200r - I'm guessing that they don't, but only because it showed up on ECMspy as a selectable feature that was not already selcted -see photo in first post-

And if it did, I don't see how it would POP in the exhaust on deccel.
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Ferocity02
Posted on Monday, August 04, 2008 - 12:21 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Yeah... my truck does that too. I was curious to how it worked on these bikes. I wonder if it will make the popping worse because it will lean out the motor, or maybe there won't even be enough fuel to make it pop?
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Mnbueller
Posted on Monday, August 04, 2008 - 05:42 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

So I tested this feature out on my way home and so far I like it! No popping at all. The only part that takes some getting use to is when you pull in the clutch before you stop the engine dips down to around 600-800 rpm and for half a second sounds like it might die, but it never did. Fuel on/off is mostly seamless. And now I guess we'll just have to wait see over time if it has any effect on fuel economy or not, but so far I'm keeping it!
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Mr2shim
Posted on Monday, August 04, 2008 - 05:55 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

It says in the tuning guide to not remove all the fuel because the engine needs some to keep combustion chamber lubricated i imagine.

"closed throttle overrun(the popping zone)"

Popping is usually cause by either rich mixture or air leaks in the exhaust system!

"Never remove all fuel in this area, as you need some to lubricate the engine, but try reducing it in small amounts to see if you can improve the popping. It is likely that you will not remove the popping completely."

Not telling you what to do, but I'm leery to try with my bike.



(Message edited by mr2shim on August 04, 2008)
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Id073897
Posted on Monday, August 04, 2008 - 09:44 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

It says in the tuning guide to not remove all the fuel because the engine needs some to keep combustion chamber lubricated i imagine.

Fuel is not a lubricant, but a solvent. Don't know what made Steve put this into the tuning guide.

Regards,
Gunter

(Message edited by id073897 on August 04, 2008)
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Ferocity02
Posted on Tuesday, August 05, 2008 - 12:51 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Popping is usually cause by either rich mixture or air leaks in the exhaust system!

"Never remove all fuel in this area, as you need some to lubricate the engine, but try reducing it in small amounts to see if you can improve the popping. It is likely that you will not remove the popping completely."


This is another spot where the tuning guide is wrong. The popping is almost always due to a LEAN condition. The mixture in the cylinder is too lean to ignite, so it goes out into the exhaust and then ignites. Exhaust leaks do increase the popping though. This is why adding fuel to the popping zone will eliminate the popping. Or I suppose completely removing all or most of the fuel will accomplish the same thing.
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Mr2shim
Posted on Tuesday, August 05, 2008 - 01:32 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Do you think it is safe to daily ride with fuel cutoff in decel enabled?
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Ferocity02
Posted on Tuesday, August 05, 2008 - 01:43 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Do you think it is safe to daily ride with fuel cutoff in decel enabled?

I'd have to dig deeper into what the feature actually does. Since I don't know anything about it, like when does it activate and deactivate, what conditions does it work under, how much fuel does it exactly remove, etc... I wouldn't use it on my bike. I know on my truck, the "deceleration fuel cut off" mode only remove a portion of the fuel, not ALL of it. This would be a good thing to figure out for use with EcmSpy. I'd feel much more comfortable if only a portion of the fuel was removed instead of all of it. The mileage gain would only be minimal so I'm not going to jump into it anytime soon.

(Message edited by ferocity02 on August 05, 2008)
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Id073897
Posted on Tuesday, August 05, 2008 - 02:27 am:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

It's all described in the eeprom info at the ecmspy website.

Regards,
Gunter
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Mnbueller
Posted on Thursday, August 07, 2008 - 12:42 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Well after a few more days of ridding with it. I have determined that it will only cut the fuel completely off if you are at closed throttle and above 1100 RPM.

I still haven't decided if I like it or not, with no combustion occuring on decel it is certainly quieter. but there are also those instances where I need to slow down and then jump right back on the throttle, where most of time its pretty seemless, but if I get down in low RPM around 2000 it gets kinda jerky. So we'll see what happens.....
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Swordsman
Posted on Thursday, August 07, 2008 - 01:27 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Heh, mine's ALWAYS jerky around 2k. Maybe I should give it a try....

~SM
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Typeone
Posted on Thursday, August 07, 2008 - 02:04 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

with this feature enabled, you're cutting the fuel down to 95% in a high-rpm, closed throttle decel condition.

from tests i've read about that gemini performed, this cut the decel fuel cell number by about 2, e.g. 34 was cut to ~32

my popping on decel was a lean condition, not rich. i kept taking fuel out (very small increments) but never got rid of it until i analyzed a log in MLV and saw it wanted more fuel. bingo. popping gone.. .
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Treadmarks
Posted on Thursday, August 07, 2008 - 02:45 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

I backed of the value by 5 on the bottom row and by 3 on the second row above 2900 rpm and all popping is gone.
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Tripletrouble
Posted on Thursday, August 07, 2008 - 04:23 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

Just as a reference, on my project car I run a fully programmable aftermarket ECU (Fuel&Ignition control). I have been using that feature for a few years and wouldn't go back. It cuts fuel if the throttle is below a set point and RPMs are above a set point. My only complaint is if the RPM set point is too low, it's a bit too jerky when the fuel comes back in. Most fuel injected cars have some sort of coasting compensation. I can't see it being an issue because as was stated above, fuel is not a lubricant and with zero combustion there's no additional heat being added.

Chris
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Id073897
Posted on Thursday, August 07, 2008 - 04:38 pm:   Edit Post Delete Post View Post/Check IP Print Post    Move Post (Custodian/Admin Only)

it's a bit too jerky when the fuel comes back in

IMO this is the main argument aginst decel cut off.

There's no extra rpm to set, but cut off is limited by (max. allowed) idle rpm, which is about 1400 1/min - might vary from ecm type to ecm type. Next, not the TPS signal seems to be used to signal an opening throttle, but TPS Filter (used in accel enrichment also), which is kind of a moving average and therefore a bit delayed.

Regards,
Gunter
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