When I purchased my next cobalt, the kid told me I can unplug this sensor that’s located right next to the oil cap. There’s a second one next to it which he said if I plugged it in I’d “go faster”. And when I asked him what this is, he just said “oh it’s for the supercharger ya know”. I haven’t plugged it in, any ideas what sensor this would be and how it’s going to affect my car?

 

Pictures? I'm guessing the second sensor he's talking about is that boost pressure regulator thing that the LSJ Cobalts have. It controls (along with that vacuum actuator) the boost. So in case of knock or whatever, it can pull boost. Don't do it lol.

 

I’m not home now but here is a picture off the internet of someone else’s. It’s right in that location. So I’m assuming I’ll be “going faster” by raising when it cuts off boost or something? And I don’t plan on doing it, I just would like to know what goin on under my hood at least.

 

That's what I thought. So that little canister here:


...has a diaphragm in the middle hooked to an arm. This arm operates a butterfly valve in the supercharger to allow air to bypass. Basically when under low load, there is vacuum on one side of the canister. This opens the bypass and allows you to effectively bypass the supercharger, getting you better gas mileage. When you floor it, it does the opposite and closes the bypass allowing you to build boost. That is controlled by the hose going directly to the supercharger. The other (lower) hose goes to the box you mentioned. It is a solenoid valve that basically allows/disallows that same vacuum to hit the other side of the canister. If the solenoid opens, it allows that vacuum to fight the vacuum on the other side, effectively opening the bypass, preventing boost. It is used for controlling max boost levels, boost by gear, and sudden need to dump pressure (knock/catastrophic failure).

I may be getting the vacuum thing mixed up with pressure, but the principal is the same regardless.

Hope that helps!

 

I got home and checked it out more. I also got access to the dealership info for it and along with ur reply I got a much better understanding of what’s goin on. Thanks!

 

the boost bypass actuator is help open(zero boost condition)by manifold when manifold vacuum drops (normal acceleration or wot) the bypass actuator is forced closed (bypass actuator is spring loaded) allowing you to build boost. under wot condition if the pcm see's and over boost/over temp the bypass soleniod is activated or opened to port manifold pressure to the bottom port on the bypass actuator to blow it open to dump boost