FYI, I find that I only use the average reading for my commute one way or errand. So that I have a MPG goal in mind and make adjustments to make that goal by the end of the trip.

Isn't it? There was an '89 owners manual there too, but it had been rained on, so I stuck with the '90. I actually found an '87 service manual at a different yard... They just gave it to me since I was buying a few other items. No info unit pages in that one, but I'm not one to turn down a free source of info. :)
Yeah, the current MPG reading seems to jump around too much to be preticularly useful. Oh well.
Oh, I should have mentioned this earlier, but I did my first fillup since installing this thing today. The displayed average FE reading was 25.9, that corrects to 38.85 MPG. Pump/odometer calculated FE was 39.16 MPG.
That amounts a 0.07 gallon difference in fuel metered. Sounds to me like it could be a simple matter of where the pump cutoff activated.

That is good news to hear, Bobski. The conversion unit that you figured seems very viable. As soon as I can find a schematic of the unit I'll be able to find the circuit that tells the unit how many injectors are to be counted as well as the flow rate of said injectors. I'll be sure to share info and make a how-to so we can all enjoy, lol.

Well, if you look at the green circuit board, it has a very large IC on it that just screams processor. If it is, there's no reason to try to multiply, or really do much of anything to the injector pulse signal before sending it to a processor input pin. It would be much easier to multiply the signal once it's been converted to a numerical value, which will be done anyway to calculate miles/gallon. So, the circuit you're looking for may be a line of code.
While I don't want to discourage anyone from trying, I doubt anyone here is going to be interested enough to extract the program from the procesor (assuming it has an internal ROM), decompile and interpret it as has been done with many Honda ECUs. It would probably be less time consuming to write a program from scratch to run on the superMID architecture.

This is an awesome thread!

Keep up the good work.

Before you know it salvage yards will experience a great influx of people asking for 'those Legend trip computers'. :)

Too bad my local junkyards don't seem to have any. They just crushed all of them at my favorite yard :( . Did any of the hondas from that era have the same trip computer? Otherwise I am going to look into using a trip computer out of some other car, too bad because you guys provided all the info to make this one work. It would be hard to know if you got all the guts needed to make a diff one work and then you have to figure out the wiring.

Did any of the hondas from that era have the same trip computer?

Not that I've seen. Maybe something in foreign markets.

Hey Bobski, your mpg is climbing nicely, is that display mounted and helping?