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Hi, I'm new here, so I'm hoping this question comes up often enough that someone will know the answer. I recently got a ScangaugeII for my Focus ('07 ZX4 MTX) hoping to better track my fuel economy. Here's my problem. From what I've read my car should have deceleration fuel cutoff, but the Scangauge does not register it. I've set the "cutoff" value to 4 above idle TPS (22 and 18 respectively). I've tried tapping the brakes when decelerating. I've tried deceleration with higher rpms. I've tried disconnecting/reconnecting the Scangauge. Oddly it does not read an open loop on deceleration (although it will read "open lp" at startup). Instantaneous fuel economy generally reads around 100 mpg when coating in gear (maybe 20% higher when coasting in neutral). Any thoughts on how I can remedy this? Is DFCO even active? When does it kick in on your car?
 

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if the injectors shut off, the engine would die.

they may just limit flow though... but with my wideband, when i am slowing down in neutral, it leans out pretty good then starts going back to lambada... which is perfect A/F ratio...
 

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or old mexican song that was made popular in the US in the 80'2....(labamba)
 

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dfco usually occurs when over 50 mph for cars 05 and up, 30 for cars older. r u testing it then? it is also dependent on the transmission. in the mtx, i believe you have to tap the brakes and not touch the gas. the atx, just let off the gas.
 

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Discussion Starter #8
dfco usually occurs when over 50 mph for cars 05 and up, 30 for cars older. r u testing it then? it is also dependent on the transmission. in the mtx, i believe you have to tap the brakes and not touch the gas. the atx, just let off the gas.
Over 50 mph? Most of my cruising is around that speed.
 

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then u should be seeing it, so long as u are above that. u are mtx right? r u tapping the brakes, giving it a couple seconds to register?
 

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Discussion Starter #10
then u should be seeing it, so long as u are above that. u are mtx right? r u tapping the brakes, giving it a couple seconds to register?
Tried tapping the brakes cruising at 60-65 today... Didn't register dfco on the Scangauge. It feels like it's active though, I can feel the engine drag on the car. I tried resetting the SG back to default settings again. Tried unplugging and replugging again. Nothing. I'm going to send an email to Linear Logic to see if they can help.
 

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yeah, u should....i know a few guys on the jet who use a scangauge and they are able to read it every time.
 

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The injectors won't "shut off", but they will start to apply less fuel than normal when coasting to a lower speed. The Open Loop should only be seen when you cold start your car and the O2 sensors aren't warm enough. You will notice this when you first start it and your RPMS will hang high for a minute or two... then it will switch over to relying on the O2 sensors
 

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Correct you should only see open loop at start up till it times out and switches to closed loop and when you go WOT you will be in open loop

When you lift you are going into a decel fuel cut and is calculated in many ways , RPM ,load,etc but it is happening . It would surprise me if you devise could record this they are very limited in what they can read but it is happening

Tom
 

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Discussion Starter #14
The injectors won't "shut off", but they will start to apply less fuel than normal when coasting to a lower speed. The Open Loop should only be seen when you cold start your car and the O2 sensors aren't warm enough. You will notice this when you first start it and your RPMS will hang high for a minute or two... then it will switch over to relying on the O2 sensors
Then I'm confused. I know it goes open loop at startup, but the way the SG reads dfco is by sensing throttle position (below a certain threshold) and open loop. If you're saying it NEVER goes to open loop (except under wot/at startup), then the SG should never sense dfco. This is what I've been seeing, but doesn't explain why so many other Focus drivers see dfco on their SG's.
 

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which do u have again? maybe it isnt calibrated correctly. but no, it will not go back to open loop unless u go WOT.
 

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Discussion Starter #16
which do u have again? maybe it isnt calibrated correctly. but no, it will not go back to open loop unless u go WOT.
I have the 2.0L Duratec (non-CA) with 5-spd.

I've posted this on Focaljet too, and there people seem to have no problems with Scangauge registering 9999mpg. Maybe this is turning into too technical a question about engine management and data that is read through the OBD-II port, but the way I understand it, the Scangauge will NOT read 9999mpg unless it registers two things: tps below a certain threshold, and open loop engine management. If the car never goes to open loop except under wot and at startup, then the Scangauge can never read 9999mpg. Except that it apparently does for everyone except me. I've tried the "tricks": above 50 mph, tap the brakes, in fifth gear, flashing my high beams, consulting with witch doctors, and changing religion and political party. None of it works, and it gets frustrating.

I'm still waiting for a response from Linear Logic...
 

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I've tried the "tricks": above 50 mph, tap the brakes, in fifth gear, flashing my high beams, consulting with witch doctors, and changing religion and political party.
lmao. I really started laughing at this. [hah] Hopefully you figure it out.


One question, besides this problem do you like the scanguage, I've thought about getting one but was it really worth it to you and other people that have it?
 

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so maybe we are looking at this the wrong way. maybe its not the car, or u. maybe u have a bad SG. which verison do u have again?

and they are cool if u are into monitoring everything urcar does, and datalogging. it helps to diagnose issues, but if u dont get into all that, theres no point.
 

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Discussion Starter #19
I have a ScangaugeII, version 3.15. I like it, except for this issue. I've been able to tell my tach and speedo are off a little bit. But it's helped me become a more efficient driver -- much to the chagrin of people who happen to be following me.
 

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what do u mean by that...more efficient?

yeah, so i am guessing you found out the speedo/mph gauge are set a bit higher than u are really going right?
 
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