Some of this has been discussed in other threads, but let me ask specifically for your thoughts. I understand and can trouble shoot the sequential system pretty well. . .after rebuild (including good break-in period) and new BNR Stage 3 (sequential) I can't get more than 11 - 12 psi on secondary (primary is fine, all solenoids/check valves/actuators etc. are fine and working properly).
All is working fine except charge relief valve is only holding about 2 psi when tested with mityvac (aha, I think! I have found the problem). Just received new ($120) CRV from Ray and tested it before install and it too holds only 2 psi! Interesting that neither the A or B side hold pressure, but both hold vacuum
[I have also noted before that the instructions in http://www.autosportracetech.com/RX-...leshooting.htm for testing the CRV seem to be backward when they say "With nothing connected to port (A), verify that port (B) can hold 15 psi of pressure and/or that port (C) can hold 30 inHg." It seems to me it must be port C that should hold 15 psi?]
Finally -- the question: Am I testing something incorrectly or are there juat new bad CRV valves floating around? Should I have Ray send another or just try to substitute an aftermarket BOV for the CRV? Does anyone know of one that works well and is easy to substitute?
Sorry for the long post. . .
--Jeff

 

Yes, it would seem Derek got the B and C ports switched around there. If you read the FSM you'll notice that part of the test is not specified by Mazda, so anyway.

If you can't get port c to hold pressure when there is vacuum on port A you have a bad valve. (Or if you prefer vacuum, 30inHg on Port B when there is vacuum on port A). It's odd that you might have two bad ones, but maybe it's possible(?)

How are you doing the test? I would connect a short run of hose to port A and then a check valve. Now use your Mityvac to draw 10in Hg and the check valve will hold it. Now connect the Mityvac to Port C or B and test the pressure/vacuum. If you have a spare boost gauge tee that in between port A and the check valve to ensure it's not bleeding down.

Dave

 

First, thanks for responding Dave. I have read many of your helpful posts and actually have your twinturbo.pdf stored as a "favorite." (will these cars make you crazy or what?) Anyway, if I understand the CRV (Charge Relief Valve) correctly, when there is vacuum to the "A" nipple B and C should be wide open (and they are). So i have been checking whether "C" holds pressure with nothing on "A" or "B".

 

I just wonder if your test setup is the issue.

Since performing this test and generating 15psi on a 3/4" hose so technically difficult, try running the car with the CRV disconnected from the airbox. You should hear it quite clearly, and really it is the ultimate test of success. If it's making noise above 4400 (4500 for certain) then it's a problem.

Dave

 

Good point. I could also hook up a pressure gauge on the "B" side of the CRV and theorectically see exactly when and at what RPM's it is venting while driving (although the car should boost fine if i do that because I would be blocking the "vent" path).