HELP: Backfiring in the intake and 20 PSI of boost

[Tim Penasack]

The subject line says it all and I think that they are related:

86 4ktq Rally car
 - running a 1987-88 5k MC-1 engine with a single knock sensor
 - running the Charlie spring at 1 bar.
 - stock ECU
 - MAP sensor is grounded
 - I have not wired a light to read the diagnostics.
 - 5K bypass valve plumbed through the 3rd opening of the IC and into the
down pipe
 - brand new cap, rotor wires and plugs

There are no other engine modifications.

I installed the waste gate frequency valve last Thursday night and took it
for its first long test drive today.  Here is the problem(s);
- It sounds like I am getting some back fire into the intake manifold
- I am getting 20+ PSI of boost (my gauge max's out at 20)

When I disconnect the WGFV I don't get the backfire into the intake.

With our without the WGFV I get more than 20 PSI of boost - while this is
fun its not practical I will eventually blow the turbo.

Questions:

- How come the WG is not opening up after I exceed 1 bar? (WG diaphragm bad?
WGFV plumbed incorrectly? are there issues running the vacuum for the bypass
valve and for the WGFV off of the same fitting? (it comes after the throttle
body)

- Is chipping the ECU going to the resolve my problem or will it just
correct the fuel/air mixture to reflect the environment  due to the stiffer
spring?

I need to get it running smoothly very soon since I need to install a turbo
restrictor due an upcoming race in Canada.  I would like to get these issues
resolved prior to installing the restrictor (less variables to contend with)

Thanks I am open to any ideas
-Tim