Detailed Fuel Consumption Data

[Capcom]

I have an idea for fuel consumption measures at idle.
Why not scangauge and OEM "Trip Computer" manufacturers seperate the MPG data with and without idling ?

Lets say the trip computer has a "more detailed" function that also shows the MPG in various speeds like:

Overall MPG = 26

Detailed:
MPG without "0" speed = 33
MPG between 0-10 mph = 9 %5 of distance traveled
MPG Between 10-20 mph = 14 %17 of distance
MPG between 30-40 mph = 28 %23 of distance
MPG between 40-50 mph = 49 %55 of distance
MPG between 50-60 mph = (NA) %0 of distance
etc..
or
MPG at 1st gear: 6 %4 of distance traveled
MPG at 2nd gear: 12 %12 of distance
MPG at 3rd gear: 34 %27 of distance
MPG at 4th gear: 47 %57 of distance
etc..

Do you know aftermarket manufacturers or OEM trip computers that give this kind of detailed fuel consumption datas ?
If not: i think it can be done by having an OBD2 scanner interface between a PDA or Notebook computer and writing the appropriate application for it.

[Matt Timion]

This would be very helpful, but unfortunately I do not think too many people care about detailed information such as this. I feel it would probably have to be a custom application made by an enthusiast.

Unfortunely this type of thing is only easily doable on obd2 cars, which a lot of us do not have.

Actually, maybe SVOBoy can help with datalogging on obd1 ECUs and we can figure out a way to monitor gas mileage using datalogging.

[SVOboy]

Originally Posted by Matt Timion

Actually, maybe SVOBoy can help with datalogging on obd1 ECUs and we can figure out a way to monitor gas mileage using datalogging.

Took me forever to respond, but here's the deal on this. ECU does its junk by time the injectors are open, so you could figure out the fuel consumption, but you'd have to have the car tuned perfectly and run in open loop (no 02 input) so that it wouldn't get hit with a lot of correction factors. This would negate things like a warm air intake, because it would assume a certain temperature, though if you normalized the intake temperature you could figure this out so you still got the benefit easily enough. Also, at this point, you'd have to whip up your own program (I could do it with an *** load of effort, ), and run the crap always on a laptop. I dunno about making a display that's run standalone usb stuff, hmm.

[CruiseControl]

The Lincoln Town Cars that I drive are from 00 to 05, and they have a display to show an approximate MPG at a given time. The displayed MPG does not change when the car is stopped, although it does when the car is moving slowly. Would it be possible to piggyback in an ECU from a newer car to read the data from an older car?

[Matt Timion]

Originally Posted by CruiseControl

The Lincoln Town Cars that I drive are from 00 to 05, and they have a display to show an approximate MPG at a given time. The displayed MPG does not change when the car is stopped, although it does when the car is moving slowly. Would it be possible to piggyback in an ECU from a newer car to read the data from an older car?

that's probably the best idea yet. piggy back a obd2 ECU to an obd1 one. The only problem is that you'd have to have the same fuel maps, etc. I'm sure it's doable with a little tweaking.

[SVOboy]

that's probably the best idea yet. piggy back a obd2 ECU to an obd1 one. The only problem is that you'd have to have the same fuel maps, etc. I'm sure it's doable with a little tweaking.

Little tweaking on an obd2 honda ecu (the most hacked ecus available) means thousands of dollars of effort trying to chip it, if it's even possible. Not to mention that older cars cannot be converted to run obd2 stuff because of the thousands you would spend fitting it with new everything, soooooooo many sensor. Not to mention that the stuff doesn't really plug up, and in some cases (honda obd2 - obd0) you would need all new dizzy and bunches of engine crap. It's just not gonna fly. I think working with megasquirt might be the way to go for non-honda people, but they have nothing for fuel economy that I know of. Even for super easy totally cracked honda ecus it'd take wicked smart people a while to get it done properly, and even longer to make a standalone thingy.

[MetroMPG]

for non-obd2 people... do you actually need to see mpg calculations?

e.g. is there a tool that would let you monitor efficiency by logging MAF or MAP readings? both would decrease as you increased efficiency, wouldn't they? (for a given speed, I mean.)

you'd just need an "average" function to make it useful. (i've found that most of the instantaneous data from the scangauge is pretty much useless because it changes rapidly and constantly).

[SVOboy]

The vacuum gauges suck, so much so that it makes it difficult to figure out what's going on. Scanguage has the trip stuff, so you can make the same trip and compare, but a vacuum gauge and other low-tech junk won't do it.

[MetroMPG]

i agree - a vacuum gauge won't be that useful. but i was thinking more along the lines of digital tools that could do datalogging.

i'm not familiar with pre-obd2. but i just assumed (maybe wrongly) that you could get at least *some* of the electronically monitored info that you can get out of the newer cars.

[Matt Timion]

Originally Posted by MetroMPG

i agree - a vacuum gauge won't be that useful. but i was thinking more along the lines of digital tools that could do datalogging.

i'm not familiar with pre-obd2. but i just assumed (maybe wrongly) that you could get at least *some* of the electronically monitored info that you can get out of the newer cars.

Flatland2d and Iwere brainstorming a while back on a way to do this. We thought that maybe you could record the injector pulses and calibrate it with real world fuel economy so it would be accurate with your vehicle. I can't think of why this wouldn't work. It might take a bit of calibrating though to make it accurate.

There is a version of the zemco fuel saver that can be used on obd0 and obd1 fuel injected cars but it requires a second sensor that I'm certain no longer exists. obd0 and obd1 carbed cars can use the zemco fuel saver to calculate mpg with no problem.