Is this possible? Eco LEDs on rev counter

[Eric839]

Hi there!
I had this idea and wanted to check with you guys to see if it's possible.

I once drove a 1993 Toyota Corolla that had 2 LEDs on the rev counter to help you monitor your fuel consumption. I'm colourblind but it must be a red one and a green one
Anyway, I'd like to make something like that in my car. I know it's not very helpful but it would be a nice project for me. In my mind, the red LED must be connected to the injectors and when fuel is injected it lights up and the green one lights when no fuel is injected, in deceleration, right?
What do you think?
If this is how it works, would you help me with a schematic so i can test it?
I leave a picture of the instrument panel so you can see what i'm talking about.
Thanks a lot!

[Baltothewolf]

You could almost have one LED hooked up to the injectors that lights up different colors depending if it's receiving power or not (external power source needed). Then the signal wire would go to the pulse side of the injector, and when there is no pulse, I.E DFCO or EOC, it would be green due to no power. When not in DFCO, or not EOC, it would be red.

[Eric839]

That sounds even more interesting! How does it work? It must be a "special" kind of led, right? I'm still a newbie on electronics.

[some_other_dave]

A regular LED might very well do that, but you'd have to get very skilled in reading the brightness/dimness (or outright flashing if it got slow enough) to make any sense out of it.

To make something that told you your actual fuel economy, you'd have to figure out how to drive that. And that's pretty non-trivial if you don't already know how to do it.

-soD

[cRiPpLe_rOoStEr]

Are you sure you weren't talking about shift-lights on that Corolla? Anyway, in Brazil some Fiats have been fitted with an "econometer", but this one is a conventional gauge. It resembles an RPM gauge or a vacuum meter, but I'm not so sure about its operating principle.

[Demolite]

I have the economy lights in my 1993 Toyota Carina E. The ecu controls them, and they seem to operate on map-sensor output (~engine load). The orange light switches on when vacuum is high as to indicate the engine is working too hard to get good fuel economy. Looking at my mpguino, the light seems to switch at 9L/100km in highway driving = only when accellerating. I have noticed the economy lights are of no use in normal driving.

A vacuum gauge or a mpguino is much more helpful. Maybe a oxygen sensor signal meter to try to stay in closed loop?

If you really want the economy leds, I would suggest a comparator circuit for the manifold absolute pressure (map) -sensor output as to determine a specific load to stay under when driving. This only works if your car has a map-sensor...

[freebeard]

It's actually a common practice.

http://www.amazon.com/Sunpro-CP7914-Super-Chrome-Tachometer/dp/B001M51IDK


http://www.summitracing.com/parts/sww-114919

Lights added to tachometers can indicate shift points, red-line or oil pressure. Why not an econometer.

[dirtydave]

torque can do it.

you can make an "alarm" for any gauge
it starts blinking or has a audio alarm

make it so it watches the throttle position sensor so if you put you foot in too heavy


if you go over 3k rpm`s
it could watch the map sensor
it can go off if you go over a set speed
hell you could make it go off if you get anything less than 9999MPG

you could make it a horrible noise and wear headphones cranked up if you need that kind of "training"