ScanGauge worth it?
 

I have a stock unit that tells me MPG and average, etc. but with past experiences I feel the ScanGauge will still be worth it...

opinions?

Probably, :)

I bought one for the other stuff, for example my vehicle doesn't have a stock trans temp. gauge and I use the vehicle brutally, in Arizona (yes, I have an aftermarket cooler fitted) - as well I enjoy the benefit of being able to check SES light codes, clear them if necessary, and use the assorted gauges to diagnose problems which periodically arise on an aging vehicle.

TBH I hardly use the MPG features.. I drive how I drive and haven't felt the need to correct my habits - I get ~20mpg in a lifted conventional 4x4 on all terrain tires, what more should I expect?

I love mine because I am an information junky, I love being able to see all the stuff that that the factory gauge cluster doesn't tell you, like TPS, IAT, engine load, exact coolant temperature, etc etc. And having a code reader comes in handy too. TPS and load are very useful for improving your driving technique to increase fuel economy.

I think it's worthwhile just for the temperature functions. I run a radiator block & hot air intake and do most of my driving in mountains, so having an actual readout rather than the useless OEM temperature gauge lets me know when it's time to pull the block out.

The other functions range from interesting (things like battery voltage & engine load) to possibly useful someday (the code reading & clearing), but the fuel consumption ones don't seem to be accurate at all. They'll give sometimes wildly different numbers than the Insight's internal gauges - and those check pretty well with the numbers I got from recording miles & gallons.

"Worth it"? Depends on how much of a data nerd you are, and if you're up to the task of diagnosis if anything ever goes wrong with your vehicle. It can be really useful there.

A properly calibrated MPGuino will be more consistently accurate with fuel consumption readings than the SG, based on the different ways they calculate fuel use.

I've used my SG to diagnose a vacuum leak (via MAP readings) that didn't even set off a trouble code.

I'm sure you already know the SG doesn't factor lean burn into its MPG calcs, right? The Guino does, however.

In my opinion, the SG's weak point is its calculations of non-stoich conditions MPG (including open loop during warm-up or strong acceleration).

When I get my $S@^ together, I'll have both the SG and Guino in my vehicle.

I don't really know much about the internals of either, but was under the impression that they apply various algorithms to estimate fuel consumption from the OBDI-accessible info, while the Honda OEM display computes fuel consumption by adding up the amount of fuel the ECU tells the injectors to deliver. A lot more accurate, but hard to do unless you're the one writing the ECU code.

Please allow a little stretching of the subject. This welcoming site and thread looks like the closest place where I can say what I want to say below.
To the OP, I envy you because you already have a stock mpg device on your car, but forgive my technical illiteracy, I am still waiting for the availability of an easy to install, fool proof and calibration free plug and play device that can be used in my Matrix to show me the instant mpg data. It has to be available in the shops, not just on the internet. Impossible to make such a thing? Look at the add-on GPS units that are so widely available. Too bad they don't show mpg numbers directly.
I will arbitrarily deem such a device to be worth of its price if I can recoup the money that I pay for it in five years (about 40,000 kms) through the achievement of better FE (I am currently beating EPA ratings by a few % and believe that I can do better). Having been here for some time, I am already "infected" by everybody's enthusiasm about saving fuel and protecting the environment. However, my lack of a technical background makes me feel like an outcast (time to have a thread or sub-forum designed to attract laymen/beginners;)). I am sincerely waiting to buy the device that I have described with a ton of patience:turtle:.
Someone please tell the manufacturers. It should not be difficult to make something like what I want. Many things that looked like a dream yesterday have become reality today:). The add-on MP3, blue tooth and GPS units are good examples.

The difference between those and and a mpg unit is that they're stand-alone units which need nothing from the car except a 12-volt power connection.

Yes, the ScanGauge is worth it. I've recouped much cost in gas with it, and have learned to drive much more efficiently.

Granted, I do drive a semi-FSP. The techniques can be transferred to any car.

Yes, that's what the SG does (and why it doesn't do as well with lean-burn equipped engines).

The MPGuino directly monitors an injector signal, so it's more like your car's MPG system. Lean burn doesn't faze it, since it's just counting injector pulses.