Charge Control Acuator quesion
 

OK, what is the proper way to test this thing? It has a vacuum and a pressure port right?

If I apply 6" of vacuum to chamber A on the diagram, the rod moves in and stays in until I release the vacuum.

What happens to chamber B to cause it to open (which I assume is the rod being out of the actuator) and allow the second turbo to come online?

If I apply vacuum to chamber B while still holding vacuum on chamber A, the rod moves out, but won't stay out, it comes back in after a second or two.

I'm trying to troubleshoot a second turbo not coming online (boost is 10psi solid on the primary) at 4500, I hear a fluttering type sound, and no boost.

TIA for any info.

The CCV spring will push out the rod (and open the butterfly valve in the Y-pipe) if the pressure at port A and B are equal. Chamber B (if that's the one on the firewall side) gets primary boost. Chamber A is connected to the charge control solenoid which supplies a vacuum until 4500 and then secondary boost. If everything is working properly at 4500 primary will be ~10 psi and so will secondary, so the door opens.

In my case, chamber A wasn't holding a vacuum...I think there was leakage between the two sides actually. So it would sort of intermittently work, but I would often not get proper primary boost, as the door was open allowing most of the primary boost to escape via the CRV and possibly the secondary turbo and intake. When that part did work, I would also sometimes get that fluttering sound with low boost...so I think you're on the right track. However, I think chamber B leakage is OK...at least the good one I checked wouldn't hold it steady either. I'm guessing it leaks out around the lever arm. I don't think it matters because under boost that port is getting a constant feed of 10psi, more than enough to keep that chamber pressurized.

Note that all comparisons to my situation are suspect as I haven't really proven anything yet. I'm pretty sure I'm right, but I f***ed something up when I put it back together so I can't test it properly yet.

jds