Hi. New here. I have a '94 SSEi that I got at 100k miles, now at 142k. It seems from what I have read that I am getting too much boost. The gauge reads +1 or so at idle +2 with a/c on. It jumps to 5 or more when i touch the gas, and it maxes out at 1/2 throttle or so. At idle, the rod in the BCA is almost fully extended, down by the supercharger bolt. Removing the top vac hose extends it just a bit more. removing the bottom brings it all the way up. In either position, I see no change in the boost reading at the gauge. Could this be the BCS?
I also have a SES light, only once the engine is hot and when I let off of the gas. Once on, it stays on, with a p1640 code, or so I'm told. (don't know if the boost is related to the light but it might be a clue).

If removing the bottom makes the rod go all the way up, the BCS is bad. It'* fairly cheap and easy to replace. The fact that the boost needle responds to throttle input, means the MAP is working, but maybe not properly. If you turn the car on, but don't start the engine, where does the boost needle settle?

Thanks for the reply. It settles at +10 with the ignition on, engine off. As for the BCS, will I have to go to a dealer to buy one? Or will any auto parts store have one?

I can't remember if parts stores will have the BCS. And if your boost needle settles at +10, you need a new MAP sensor, most likely. It should settle at or near 0.

Thanks a bunch. Very helpful.