Civic DFCO Conditions
 

I remember reading this at one point, but just spent what seemed like forever searching as many different terms as I could to try and find it, to no avail.

Anyone have a link to the conditions that need to be met in a Civic for DFCO? If it matters, my car is a '95 DX.

if you have a convenient kill switch (mine is a small microswitch on the gear shifter) you can tell when you are NOT in dfco, as the sound will change when you hit the button and you may notice a faster deceleration.

if you have a mpguino, your instant gph should go to zero and your instant mpg should go to 999999 when in dfco

FYI, I don't think an OBD II open loop indicator necessarily means dfco, could mean any change from closed loop. In fact now that I think about it, the metro would show open loop any time I decelerated in gear, but later monitoring of the injector revealed more specific conditions.

iirc, my metro would not go into dfco unless I was going above 40mph and would drop out of dfco (start burning fuel again) at about 25mph, in top gear.

This might be a good wiki candidate too to "publish" different dfco conditions for different cars
http://ecomodder.com/wiki/index.php/Main_Page

On my 1996, it has to be in gear, foot off the pedal, and above 1200 rpm. If you try a few coast-downs, you can feel a "surge" when the fuel flow comes back on. Our cars are different generations, sort of, but both have D-series engines.

With a DX, I'm assuming you also, like me, have no tachometer. Note the speed and which gear you're in for the coast-down, and you can calculate the rpm. Example: Max speed in 2nd gear is 62 mph. DFCO shuts down (surges) at 11 mph. Max rpm is 6900. 6900*(11/62) = 1224 rpm.

I can feel it in the lower gears, but not in the higher... One of the main things that I was wondering about was if it was linked to the brake switch as well. That is part of the reason I was looking for the post, because whatever post I remember reading I almost want to say that it says the DFCO kicks off (or in other words the injectors start again) when the brake is pressed. I did some DFCO last tank but did brake while decelerating in gear (normally I just shift to neutral while braking) and MPG went down... So I was trying to prove (to myself at least) that this was because I was failing to DFCO because I was braking.

Does not apply... I swapped in a tach a while back, but you are correct, it did not have one originally. ;)

Maybe I should just wait and not try to DFCO until I have my MPGuino hooked up (currently started assembling the parts last night I had acquired to build my own "kit").

Just wish I could find the information that I remember reading. I do not remember if it was on here or somewhere else... And hell, for that matter it could have even been for another car (not the Civic) and I just made it up in my mind that it was for the Civic... lol Would not be the first time I remembered something incorrectly.

If I do find it though, I might try and figure out how to add it to the wiki and start a DFCO condition list.

Also, be aware of this: Even if it stays in DFCO down to 1200, it may not enter DFCO unless you're above 1500 or so.

Not true on mine. Engine braking above 1200 rpm, triggers an Open Loop status on the ECU, which indicates DFCO.

I try to avoid dfco. It's more efficient to start an EOC glide earlier, than to burn a little more gas and then bleed it off through any kind of braking. DFCO is braking.

Yeah, but most of the hills that I go down have stop lights at the bottom of them that during my daily commute I would say I get stopped at them 80% of the time. I actually saw a decrease in MPG when I would EOC on my daily commute. If I can DFCO down the hill, it would be great, because more than likely I will have to brake anyway.

But again, that is why I want to know the conditions, because if using the brake causes it to kick out of DFCO, that would be good to know so I could just neutral coast rather than trying to DFCO when it wont.

Ah, I see. I don't know about using the brakes and whether that cancels the DFCO condition. Sorry.

No big deal... I do not know about it for sure either... lol Thus the reason for this post :p:thumbup:

Guess I will do some testing when I get my MPGuino up and running. I am beginning to feel like I just made up that post I think I remember... lol

I've never noticed the brakes kill DFCO on any vehicle I've driven.