1987 Chassis Buick Service Manual vol.1, page "6E3-A3-90 Driveability and Emissions - Fuel Injection (Port)", is trouble shooting the EGR page when you get a code 32. Even if you don't have a code 32, it has very useful diagnostic info to help pinpoint the issue. But from what you posted, you might already be working from this page.
In this link, you want to click on 6-Engine.pdf and go to page # 218.
This gives the overview and circuit description.
There is also another page with the same name just different page number that exists. But it depends on which version of the service manual you have. It's the same info as above. Page #, "6E3-A4-68"
I would start by checking the obvious items, like the vacuum hoses that may be heat cracked or leaking that feed the solenoid, all of your wiring and the fuseable link that powers it. But I'll be honest, I have never had to diagnose an EGR failure or in-op condition on any of the cars I've owned. Typically, this particular system is one of the first things that finds a home in the spare parts box. But I feel your pain. Especially if you are having to deal with emissions and it won't pass because of a mechanical / electrical issue like this.
Maybe someone else can chime in whose had to deal with this before.
Hope some of this helps.
Thanks, and yes I have been through the service manual diagnosis, and even threw an ECM and EGR solenoid at it anyhow, but still nothing. That's why I'm curious about the operating parameters and if maybe one is not being met. I have been unable to find those parameters. I did see one post in here about the wheels need to be rolling (VSS input), but I still see nothing.
Yesterday I did short-test the two solenoids I have by grounding terminal H at the ALDL. Interestingly I did not hear or feel any solenoid function from either. Maybe it is as simple as two dead solenoids, so I ordered another. It will be a real pisser if the new one I already tried is DOA.
Have you tried to tee in a vac gauge at the egr and see if you ever get vac to it? A helper ay need to ride shotgun and monitor. Also the passage may be clogged with carbon. If you move the diaphragm up and down the idle should change, or become rougher.
I brought this up with Eric a few years ago and he said he was looking in to it, but EGR is probably the lowest priority thing for a performance tuning chip maker and a non-chip problem, so not terribly surprised it ended up falling off his to-do list. Note the last entry and the date: