You're stuck in base boost. Lots of posts on this... do some searching!

 

Whats the problem? 2/3's in the orange on the turbo gauge does not sound like a problem to me...especially if its an auto. A "stock" manual T16 FPT with red box APC(uprated vs black) will just touch the red/go 1/3 into the red on the turbo gauge depending the grade of petrol use.

What grade of petrol are you using? It makes a difference. Try hooking up a calibrated boost gauge and see what psi/bar you are making. You should see about 12-14psi/.8-.9bar at full boost on a stock FPT if everything is functioning correctly.

 

I am running BP Ultimate which is 98 octane - basically the best fuel available. I wasn't aware that the turbo gauge on the auto didn't get to full boost - surely it should if the gear is held in one or two? I have a 2004 9-3 Aero which is also an auto - with paddles tiptronic etc - when in drive this always gives full boost according to the turbo gauge. Hence the reason why I thought there was something wrong - the 900 Aero stops surging in acceleration when it hits 2/3's in the orange - which is why I thought there was an issue with the boost level. I will see if I can get a hold of a boost guage to test - where does this need to be fitted on the engine to do so - and can the boost pressure be tested with the car stationery - or does it need to be hooked up and driven as normal?

 

dmgb5 is right... base boost should be more like 1/2 through orange, if that...

An interesting test would be to pull the APC fuse or disconnect the electrical connection from the APC solenoid (next to ignition coil, has 3 vacuum lines running from it) which would certainly force base boost, then go for a drive and see if you get less.

You could also check your ignition timing, which should be set to 16 degrees BTDC with the vacuum line from the throttle body to the vacuum advance removed and the hole plugged.

 

I agree with Jeff above. Pull the solenoid plug and see if you get less boost which should be half way through the orange at base boost. If the boost reduces it suggests you are getting more than base boost with the solenoid connected. Prime targets for low max boost, provided you have decent gas in the tank, are over advanced ignition or dizzy retard capsule faulty or not operating (hose disconnected). Or a long shot; failing fuel pump or FPR.

BTW, I have always found the boost gauges to be very consistent in their readings; The orange to red boundary is 10psi, half orange is 5psi, full red is 20psi.

 

Dizzy vacuum capsule a great guess, peva!