Power FC showing 2bar of boost with just ignition on?!

[PDale]

Hi everyone, had my FD for a couple of months now, love it!
 
Had a few problems with it though recently:
 
Car has a single turbo, Apexi Power FC, GReddy Profec B 2, etc and boost has been set to 1bar. Basically the car won\'t start (fires up and then dies immediately) I noticed the Power FC controller was showing 2bar of boost with just the ignition on! Boost controller was showing zero boost. I read somewhere that you get fuel cut if the boost exceeds 0.25bar of the set boost. So I\'m guessing thats the reason the car won\'t fire up properly, cos the power fc is telling the car its overboosting? Stupid question, where does the Power FC get its boost reading from and why would it show boost without the engine running?
 
I don\'t know if any of my other problems are related, but here goes:
 
Car idles fine when fully warmed up, steady as a rock. When I am driving up to a roundabout for example, as I approach the roundabout and put the clutch in, sometimes the revs fall past idle and the car stalls and sometimes it will fall past idle to about 500rpm and bounce back up to idle (1100rpm - ported).
 
When at a standstill and holding the revs at about 3000rpm for example (as if to move off quickly, lol!) the revs can hunt between 2500 and 3000, even though at idle there is no hunting!
 
Sorry for the mini-essay! Thanks in advance, Paul.

[Carl]

Could be the MAP (Manifold air pressure )sensor which is on the firewall passenger side of engine bay behind the throttle.
A good used one would be not much money.
As for the rest of the issues it is hard to tell,but I would check for any vacuum leaks and get a compression test.
Regards
Carl

[PDale]

Cheers for the reply Carl :Thumbs-up
 
Turned ignition on today, commander was showing about 1 bar of boost, thought it should start if only showing 1 bar of boost, turned it over and it started (although running super rich, commander showing 47% injector duty on idle! Obviously the car thinks i\'m driving with 1  bar of boost!)
 
Turned car off and had a fiddle with the connector to the MAP sensor (GM 3 bar map sensor) and the commander was showing vacuum like it normally does with just the ignition on. Therefore I think its the connection to the MAP sensor thats a bit suspect and going to try using new connectors.
 
Question - When disconnecting the MAP sensor the voltage on the commander was showing about 4.87V with the sensor highlighted as being bad (because its not connected) I would have thought that the voltage would be zero as theres no return voltage when the sensor isn\'t connected. Is it a safety thing to stop you driving the car without a MAP sensor and blowing up the engine because the ecu would think there is no boost if the voltage was showing as zero?

[Carl]

The car will not run right at all without the MAP sensor connected so it is a safety thing yes.Good to know you have found the problem for that anyway\'s.
Regards
Carl