Correct setting for offset and fuel cut off for ScanGauge II for 8th Gen Civic

jwal · #11 04-09-2010, 07:06 PM

As far as fuel cutoff is concerned, what error numbers are we talking about if we disable fuel cutoff completely (i.e. cutoff set to 0)? I've read somewhere that the error difference could be as small as 0.1%. So, why bother with fuel cutoff anyway? Won't having the update set to "FAST" and disabling fuel cutoff be more accurate than the normal update rate?

PaleMelanesian · #12 04-12-2010, 01:19 PM

I have an older one with no cutoff setting, so it can't read DFCO at all. I never use DFCO anyway, so I have the calibration dead on. 1/2 gallon cumulative error over the last 18 months. If you drive in a way that doesn't use DFCO, it's irrelevant.

uabcar · #13 04-12-2010, 03:03 PM

Interesting dialog. I have the issue where dfco registers sometimes and not others. I generally have to disconnect from the port for a few seconds and re-connect - and then I'm fine again for a while. I've not been able to find a pattern that seems to trigger it. I almost never change the display variables.

Two questions after reading the recent replies-

1. based on someone’s comment, it sounds like the R18 can 'learn' not to use dfco? Is this true? If so, how/why do you think this?

2. Given the opportunity, why would you not want to use it. It seems like coasting in gear w/o fuel would outway coasting out of gear? Maybe it depends on the type of driving?

Thanks

PaleMelanesian · #14 04-12-2010, 03:22 PM

Rolling in gear is not coasting at all. It's engine braking, and is bad for mpg the same way normal braking is. It's made slightly less bad by the DFCO feature, but it's still something to be avoided in normal circumstances.

(an unexpected stop, or a long extended downhill are two reasonable exceptions)

Much better, mileage wise, to FAS and coast. Even rolling in neutral with the engine idling is better than DFCO, because you're preserving momentum. The car rolls so much farther than it can in gear. That, when viewed from the angle of a whole trip, is better than fuel-cut, even though the instant zero consumption would seem to be better than idle consumption.

uabcar · #15 04-12-2010, 03:35 PM

Quote:

Originally Posted by PaleMelanesian

Rolling in gear is not coasting at all. It's engine braking, and is bad for mpg the same way normal braking is. It's made slightly less bad by the DFCO feature, but it's still something to be avoided in normal circumstances.

(an unexpected stop, or a long extended downhill are two reasonable exceptions)

Much better, mileage wise, to FAS and coast. Even rolling in neutral with the engine idling is better than DFCO, because you're preserving momentum. The car rolls so much farther than it can in gear. That, when viewed from the angle of a whole trip, is better than fuel-cut, even though the instant zero consumption would seem to be better than idle consumption.

Gotcha. Makes sense. My route to/from work doesn't provide much chance to coast in neutral so I don't typically do it (10+ stop lights along a 9 mile route). The final leg of the trip home is perfect for a neutral glide though so I'll have to give it a whirl.

tx

phlack · #16 05-05-2010, 12:59 PM

Here are my gauges that are up:
LOD
Trip MPG
Instant MPG
LP

I have LP because it's needed to register DFCO. Take this out and it won't register 9999.
I did notice one time that, upon disconnection, it did work without the LP gauge, for maybe a week, then stopped working again.
Someday I'll try fanamingo's tip and make sure LP isn't showing up and see what happens.
I believe my TPS is at the default 24.

Speaking of the engine learning about the driver's methods, can you explain a little more about that, fanamingo? I haven't noticed any of that, but i'm not sure what to look for, or how to trigger anything like that, or if it would even help!

-Mike

fanamingo · #17 05-05-2010, 10:43 PM

I think I shift between D and N so much that the car's computer is confused. It seems to have disabled DFCO in response. I'd much rather have it enabled. Having it disabled hurts fuel economy a very small amount, but I don't know that there's anything I can do about it.

jwal · #18 05-07-2010, 08:36 AM

Right now my offset is at 8.1%. Last time I filled up, scangauge says I used 0.4 gallons more than actual. However, I had fuel cutoff disabled for the whole tank. I wonder if this is why my offset is lower than two of the posters in this thread, or if my driving habits affect the offset somehow.