Found a Civic VX; Great Mileage Starts Now! - Page 4 - Fuel Economy, Hypermiling, EcoModding News and Forum

james · 01-23-2009, 01:51 PM

That's one thing I really like about the VX. You can get 55 MPG without having to shell out 24K for a hybrid, to drive painfully slow, or be constantly turning on and off the ignition. All you have to do is keep it in good shape, drive it right, and keep the speed below 60.

Cd · 01-23-2009, 03:27 PM

I just wanted to add that the Honda fuel guage in our cars is a complete joke.

Don't trust it.

( I can drive almost 100 miles before the needle even drops below 1/8 " on the guage. At half a tank, I have driven over 250 miles, yet the next time that the car is started, the needle drops 1/4 " within two seconds.
Others here on this forum have experienced the same thing as well. )

Good luck with your mileage. (I'm envious since I have a '93 DX automatic )

NachtRitter · 01-23-2009, 08:56 PM

Ha ha... ya, don't I know it!! I admit that I am totally guesstimating how much fuel I've used so far based on the general neighborhood of where the gauge is pointing... when it more or less wanders between the full mark and the half way mark, I'm guessing the tank is roughly 3/4... and so on. I kinda panicked the first time I took a freeway onramp and my fuel level "dropped" from about the 7/8 mark to the 1/2 mark

... of course it slowly came back. Getting more used to it now.

I think my instrumentation work is going to have to include a more accurate fuel gauge. I was thinking that the MPGuino code could be modified... since it already has the ability to measure how much fuel is being used instantaneously, and since the car manufacturer provides the fuel tank capacity, it ought to be a fairly straightforward modification to provide the MPGuino with the tank capacity (minus some small amount if you want a safety margin) so that it can continuously subtract the instantaneous amount used from the total amount and then display how much is remaining in the tank (for instance, via bar graph LED). Each time you fill up and hit the tank reset, it starts over.

I do enjoy open source projects for that reason ... !

Cd · 01-23-2009, 09:12 PM

The owners manual on my DX states that I have a 11.9 gallon tank, yet I have never filled up more than around 10.5 gallons, despite the needle being several millimeters below the 'E' mark.

I'm not brave / stupid enough to test how far I can go before running out of gas. It's just hard to believe that there is still over a gallon of gas left in there. ( The car even drives funny - as if it is going to die at any moment )

Supposedly, a VX has a 10 gallon tank.

NachtRitter · 01-30-2009, 01:36 AM

Correct; owners manual for the VX states a 10 gal tank. With the needle deep in the red, I'm typically am putting in ~8ish gallons.

My thought with the MPGuino controlled fuel gauge was mainly to get a more accurate view of how much fuel I've actually got left. I'd still want to fill at about the same time.

Speaking of which, I filled again today, and the last tank I got 47.6 mpg. Not bad, but I'd hoped to do a little better than last time.

I think it's time to order the MPGuino, especially since they are available pre-assembled now...

NachtRitter · 02-02-2009, 03:54 PM

Dangit!! Just discovered that on my Honda VX, when I turn off the ignition in order to do an Engine Off Coast, the trip odo stops recording mileage ... Argh!!!

I have not yet verified if the "master odometer" also stops recording mileage...

Since I always use the trip odo for calculating my FE, and since I did a lot of EOC last tank, and since I didn't turn the ignition on until I needed to do the bump start, I probably lost about 20 miles worth of distance on my trip odo on the last tank (there are 3 times where I can coast from ~65mph down to ~55mph over 2 to 3 miles on the way down the hill to work)...

Though I knew the speedo was electronic (it goes to zero when ignition is off) I just made the naive assumption that the trip odo operated mechanically....

Guess I'm going to have to look at a better way to kill the engine (I've seen several different approaches in threads here) if I want to EOC and keep accurate track of the miles.

Daox · 02-02-2009, 04:04 PM

You can't just turn it back to on and have it work? Thats how you should be doing things. Newer cars with airbags won't work if the car is off. It also is safer since you have one less step to bump start.

NachtRitter · 02-02-2009, 08:07 PM

Ya, I can definitely do that... Mainly was irritated because I blew the last tank plus this tank as far as accurate FE is concerned...

These were supposed to be my pre-instrumentation baseline tanks...

I was thinking I should look for a better way to do EOC because even 5s between off & on at 60+ mph, I'll lose 0.1mile on the odo. OK, so it'll probably take me less time to cycle between off & on, but that's the kind of thing going through my mind...

I guess due to the fact that I'm a bit old-school, I was uncomfortable leaving the ignition on for a long time without the engine running... I recall learning that the points-based ignition system of older cars didn't always like that. Might not be a problem anymore for the electronic ignition cars...

Clev · 02-02-2009, 08:23 PM

Quote:

Originally Posted by NachtRitter

Ya, I can definitely do that... Mainly was irritated because I blew the last tank plus this tank as far as accurate FE is concerned...

These were supposed to be my pre-instrumentation baseline tanks...

I was thinking I should look for a better way to do EOC because even 5s between off & on at 60+ mph, I'll lose 0.1mile on the odo. OK, so it'll probably take me less time to cycle between off & on, but that's the kind of thing going through my mind...

I guess due to the fact that I'm a bit old-school, I was uncomfortable leaving the ignition on for a long time without the engine running... I recall learning that the points-based ignition system of older cars didn't always like that. Might not be a problem anymore for the electronic ignition cars...

I'm with you. I have the same problem on both of my cars. My problem with key on/key off is that I'm essentially turning the computer on and off many more times per day than normal. Therefore, I'd rather find a way that doesn't involve that. Somebody mentioned before that newer engines can be shut off by interrupting the camshaft or crankshaft sensor lead. Maybe yours is new enough to do this on? (Mine doesn't appear to have a camshaft or crankshaft sensor that I can find.)

NachtRitter · 02-02-2009, 11:55 PM

Ya, that's a good point too. I do have a "Crank Position Sensor", but have no idea how interrupting it would affect the engine... I may have to experiment with that ...