HELP< Electronic/computer help needed MPG related

[racprops]

I will gladdly share the system to compair counters.

Rich

[racprops]

Look I have worked long and hard to make this work.

At this time I don't even know IF it works.

That is why I am asking on help to modifide a old MPG Computer to find out.

What we come up with is open to anyone that wants to follow to use a old computer.

I found a bland spot in the MPGunio and asked for a fix.

I figure that the old system which runs a lot slower and uses a simple ground pulse trigger would be simple to fix.

Rich

[dcb]

Not sure you saw this message, it is a caveat about forcing changes to the pulse width directly:

Originally Posted by dcb

modifying pulse width has been done a number of ways, most reliable seems to be by modifying the o2 sensor signal, which tricks the ecu into a leaner mixture. If you force the injector pulse width to a different length, the system WILL attempt to compensate, as is.

counting is trivial by comparison.

Here is one discussion from 2008, keyword EFIE:

Originally Posted by dcb

Sure it is doable, a basic arduino or clone can handle it if you want to make it easier to get started. You will get the most bang for your buck by focusing on the O2 sensor IMHO, see also EFIE. Some folks have just added (subtracted?) an offset voltage to lean out the mixture, even on the narrow band sensors, but you could also hold the high signal longer or the low signal longer with the microprocessor if you wanted more precise control.

your o2 sensor cannot handle much current (an analog voltmeter used to measure its output can fry it) and is somewhat expensive though, so proceed with caution. And you already know (or will research) all the caveats of running your engine too lean.

[racprops]

Look at my record, I bought a bunch of your MPGunios and help out as best as I could.

83 posts.

Now stop fishing and help.

Rich

[racprops]

Dude I am doing nothing like that.

I know all of that.

Can you figure a way to subtract counter two from counter one and give out the differance??

Note the numbers will change due to speed and demaind... so they are not fixed.

Rich

[dcb]

I can, but I would never give up the precision (and low cost and ease of installation) of monitoring the injector pulse widths, for installing dual flow meters and writing special programs to monitor them.

There are some applications that may need dual flow meters, but I am not convinced this is one of them.

This is me helping

[racprops]

I exsplained that with my injector controler your MPGunio is blindsided, as I am not changing the ECM, and thus not changing the ECMs control of the injectors, the MPGunio does not see my changes and still reads the ECUs control and thus falsely reports the wrong MPG.

Rich

[dcb]

I would personally redo the thingy to gate the negative side of the injector with an appropriate semiconductor (i.e. n-channel or npn), and leave the mpguino attached to the injector.

[racprops]

And your right back where I already am.

The MPGunit is great for almost all systems.

BUT it reads the signal from the ECU to the Injector, and how long that ground signal is on.

I am not changing that signal.

So the MPGunio CANNOT read the real on time of the injector or of fuel fed though it and so can not do what I need.

ONLY a real time read out of the FUEL will do.

My system COULD be a MAJOR BREAKTHOUGH, all I need is a way to really read how much fuel is used.

A real time readout so I can tweek and tune it as I drive.

Give me a hand and I can prefect it or your standing in the way of a possable great idea.


Rich

[dcb]

Originally Posted by racprops

I am not changing that signal.

I do not understand why gating/chopping the negative side is not an option. It absolutely is an option with a trivial change to whatever circuit you have interrupting "b+" if you know how to do it, and will not divorce you from your current investment in fuel consumption instrumentation.

The guino won't work as-is with any random fuel hack which is no surprise, and the guino WAS here first, so you could have planned for this configuration to keep things compatible.

Switch the ground side of the injector instead of "B+" and you are done. Just invert the thing doing the switching, what is the problem?