A New Formula In Our Stall

[TopNotch]

No power -- like it's in "limp mode".

[GTRS Fiero]

Do we know if it ever ran correctly?

[Fierofool]

Yes.  It was Lee's preferred vehicle.  He ran many RFTH's with us.  His girlfriend said that it always had the check engine light on.  I don't know if that was from the inception or just long term. 

[GTRS Fiero]

So, the ECU, wiring, sensors, or voltage, or the transmission can all cause limp mode.

Of course, limp mode can cause the transmission to behave oddly.

There is the old disconnect a sensor to see if things change trick.  Likely the MAP sensor or TPS.

[TopNotch]

I ordered another ECM from Ebay, from a Buick Park Avenue, with the same number on it as the one in the car. The seller claims it's good. We'll see what happens.

[GTRS Fiero]

Is is currently believed that the problem is with the ECU itself, rather than the chip or a sensor input?

[TopNotch]

It's a "Let's see if this helps."

[GTRS Fiero]

Did you ever hear back from Ryan?

[TopNotch]

Did you ever hear back from Ryan?

Nope.

[TopNotch]

I got the "new" ECM I bought from Ebay. It had no ROM, so I used the one out of the old ECM. The car runs exactly the same.
I found a broken (chewed) wire coming from the firewall connector to the ECM, and soldered it back together. No change in performance, but all the gauges seem to be working now. I honestly can't remember which gauge didn't work before, but they all work now.
You may recall that I had replaced the throttle position sensor, but it still seems like it isn't working. I'm trying to find a diagram of the ECM, so I can check the continuity of the wiring between the TPS and the ECM.
Edit: I found a diagram online. It shows the TPS going to pins F1, E5, and E6 of the ECM. I just have to figure out where those pins are.

[GTRS Fiero]

So, the ECU itself isn't the problem.  The programming wouldn't have changed, and used to be OK, so not that.  If the stick itself was bad or not being picked up, it should give an error.

I read somewhere that the ECU will run in limp mode without that module.  If the module was unplugged, would there be a change?

I'm curious how the plugs look.  Do we know that it's running on all cylinders?

[TopNotch]

The plugs and wires are new.
Actually, the ECM/ECU is called the Powertrain Control Module in the diagram I found, so I guess we should call it the PCM. It controls both the engine and the automatic transaxle (which this car has one of). I will attempt to check the continuity of various wires this weekend.
BTW, the diagram I found is for a 94-95 Buick, Oldsmobile, or Pontiac with a L36 engine (3800). Sounds like the correct one to me.

[Fierofool]

It is a Park Avenue engine.  I think it's a 94.  There were handwritten notes inserted into the factory shop manual that detailed the engine, along with the VIN number as I recall. 

[GTRS Fiero]

Then there are the injector fuses, the fuel pressure, and the MAP sensor.  Of course, compression.  Still, it'd be interesting to know how the plugs look.

[Fierofool]

Pat installed new wires and plugs early on.  Heidi said the car always had the SES light on, but the car was still Lee's daily driver, preferred over his other two vehicles.  It's my understand that it only got parked due to Lee's declining health.