Hi Grizzlywon...
Welcome to the site. Once the '89 DX is smogged for the ownership xfer, it no longer needs to be smogged since it's 25+ years old, right? I forget when the cutoff is...
I'm selling my VX which has an MPGuino in it; if the new owner does not want it, I'd be happy to send you mine for the cost of shipping... this is what it looks like:
http://ecomodder.com/forum/showthrea...tml#post187715
If that doesn't work out, it should be pretty easy to put together your own using one of the more modern Arduino boards; wiring details for the display, buttons, and connections to the car are here:
MPGuino - EcoModder. Also check out the latest software updates here:
http://ecomodder.com/forum/showthrea...ead-26469.html