Stock Boost guage out of control at 1500 rpm

[scuba5904]

hey guys, bare with me, i just purchased a 90 gst that has boost issues or so I thought. The car is stock except for a HKS intake and a 3" Dynomax muffler. The problem that i have is that the car runs fine when it is cold but after it warms up when i try to give it gas, even when the car is sitting still, the boost guage hits 14 lbs at 1500 rpm and the engine flusters and starts flooding out, I have already fouled plugs because of this. Is this a computer problem or what, the turbo seems to be fine and even when this is happening the turbo isn't really doing what the stock guage is saying but the computer thinks that it is. I know that if you unplug the MAS that the stock guage doesn't work so I replace the MAS with one that I knew worked and it still does the same thing. I put a MBC on the car thinking that I could control this issue but even with the controller set at mininum boost it still does the same thing. I need help, I know very little about dsm's and tubocharged cars but I know how things should operate. I have been a V8 guy all these years and now i am a newbie in the dsm world. please have pitty on me and help me out......thanx guys

 

[megadeth2118]

A MBC won't allow you to reduce boost it will only let you raise it. I would say check all of your vacuum lines, but if it runs fine while cold then that's not it. Check your o2 sensor maybe? I'm still not sure why your boost gauge would jump up that high unless it's defective.

 

[scuba5904]

thanx for the input, I have talked to some guys on the phone that seem to think that it could possibly be in my ecu, being the car runs fine when cold means that it is running in open loop mode or crank up mode where it doesn't really use sensors it runs off of a set mode that is preprogrammed for cold starts but when it reaches a certian temperture it goes in to a closed loop mode where it uses the sensors in the car to monitor everything. they seem to think that in this section of the ecu that it could be defected but i really dont i just hope that there are other people out there that have run across the same thing...