: About to buy 81 Deville, Need help from forum user Adrian12

12-21-06, 05:55 PM
Hello, first post for me

I about to pick up a cherry looking 1981 Deville and greatly look forward to making it 'mine'. I'm an electrical engineer so not only will this caddy satisfy my nostalgia for a previous big white boat (..RIP sperm-cicle...) but I see it as a huge blank slate for a variety of electronic devices.

The custom carputer market these days is pretty complete with every bell and whistle you could imagine, almost all of which I should be able to integrate in this beast. The one thing Ive had a h*ll of a time finding is the interface definition to the ALDL diagnostics port of the 81 Deville. The fact that this car even has an OBD like interface is ridiculously amazing and I would be remiss not to utilize it.

This is where forum user Adrian12 comes in. From the looks of some threads Ive dug up, it appears you have a definition file for TunerPro. Unfortunately I am unable to PM you but would LLoooovvvveee to have the neccesary definition file.

The thought of finishing off my touchscreen computer/gps/mp3/navigation/kitchensink system with diagnostic information and perhaps even 'live' data makes me tingle.

Can you or anyone else with the holy grail of 81 Deville software help?

Many thanks in advance!!!


12-21-06, 08:02 PM
I can tell you're more electronics guy than car guy, otherwise you'd probably use a modern FI controller... but good luck with that one.

12-21-06, 08:14 PM
You're absolutely right, I'm definitely an electronics guy since I never had much of a chance to figure out cars. After spending sometime on the forum I see I am going to have to learn a bit more about cars in general and certainly this beast.

A modern engine computer would be great but it's going to take me some time and some googling to figure that one out. Thanks for the idea though!

When I get this thing I'm going to have to post some pics, except for a small ding in the center of the rear bumper that looks suspiciously like a light post (thanks to whosever grandma was driving this thing) it looks like the day it was made.

Thanks again,

The Ape Man
12-22-06, 05:59 PM
You might want to get a shop manual. It's written by engineers for engineering dropouts. Plenty of trouble tree stuff but no ALDL interface specifics. That system is not the same as the other GM CCC systems of the era. It was known as DEFI and was used for quite a few years after '81. All you need do is press the off and warmer buttons (at the same instant) on the climate control with the ignition switch on. The compuker will then start to spit out information. It will end up with a diagniostic routine known as a switch test. All in the book.

Love to tinker?
Replace it with this:

Probably little improvement except for reliability and ease of parts sourcing though.

12-22-06, 09:20 PM
Good info, thanks. All of my manuals are still in the mail unfortunately. Looks like Ill have to live with the ECC interface for the moment.

Megasquirt would be pretty sweet but it would definitely be a bit of tinkering to make it work well with the 864. I could of course disable the 864 feature but the novelty of an '81 with DOD makes me want to keep it until it drives me nuts.

The 864 on my last 81 worked pretty well... most of the time. It was great getting 25 mpg but every now and then it didnt want to switch back to 8, which generally meant a lot of chunking at the first stop after the off ramp. Ahh.. memories.