[fleetwood96]

OK gang, I have the wiring figured out! With the help of the service manual, I was able to figure out that one of the two wires at the transmission has nothing to do with the 3rd gear switch to the ECM, rather, it is a "kick-down" switch that's attached to the gas pedal which feeds +12v to the transmission when you have the gas pedal at (or near) the floorboard. That part works fine, but the Ground wire out of the transmission when it is in 3rd gear mode wasn't working (and still isn't working). I take it to see what's wrong you would have to drain the transmission & remove the trans pan and filter to see what's going on. I also discovered another problem, someone had cut the same wire at the ECM (under the glove box) to disable the 6 & 4 cylinder modes.

So... what I decided to do is attach a relay to the dash cruise control switch. With the switch ON, ground is fed to the ECM (like the 3rd gear switch mode would). When crusing around town, etc, with the cruise switch off, I get 8cyl mode all the time. Not a bad compromise, in my opinion...

One thing I noticed about the 8-6-4 operation, around 35mph at steady speed or small accelerations around town (and the system ON), the computer wants to switch back and forth between 8 and 4 cyl modes and won't even use the 6cyl mode. This makes the car feel "jerky" at these low speeds when it switches modes. Around 50mph or so, the computer will take the car into 6cyl mode and then eventually 4 cyl mode, which is less noticable, but like another member has stated, the 6 cyl mode definitely feels "nervous" (could it be because one side of the engine has all 4 cylinders going while the other side just has 2, therefore it's unbalanced?). Anyhow, I can tell when it's in 6cyl mode just by the feel of the car, without even looking at the MPG readout.

Another thing that's pretty clear is that 4cyl mode has next to no power whatsoever. It works fine if you're cruising along level at 55mph with the cruise set, but anything above 65 or so, or with any sort of wind and you're constantly back & forth between 4 and 6 cyls (or 6 & 8cyl depending on wind, speed, and going up hills) with the cruise set.

Anyhow, that's my experience so far.... I'm still glad I got her - she's been a blast to work on and drive!! I've also heard that GM is definitely going to try this "Displacement on Demand" technology on some 2005 (and beyond) products, so it will be interesting to me how they do with it 24 years since the '81 attempt! Doug