whats the factory boost gauge ran though?

[spocks90talon]

ok so i thought my ecu was bad in my 91 gsx but i was fiddling around in my car today i noticed that when i turned my key the to run posistion the factory boost gauge didnt go up to zero like it used to when the car ran. i got to thinking and rememberd that the factory boost gauge is ran thought the ignitor or the power transister or whatever you wanna call it so i thought if my factory boost gauge isnt working that must mean the ignitor is bad which is why my cars not getting any spark right? am i right? i may be wrong but i looked up the wiring diagram in my haynes and that what it looks like please tell me im getting close to figuring this out because i dont wannt have to drop $200 on a ecu when i really should be buying a new blow off valve with that money

 

[spocks90talon]

ok i did a little research here and it looks like if my boost gauge isnt moving than my ecu is bad right?

 

[Defiant]

The needle is run by the ECU, after it determines from five or six or so sensors what the boost should be running. When you put on a real gauge, you will be surprised at how well it does its guessing.
I don't know if non-zeroing is an indication of ECU problems.