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Low boost issue not related to BBv help please

S

Smikey

New member
I have a 99 gt that has been top swapped it's got a mild cam and a 3.2 pulley and a customs tune the issue I'm having is the car only makes 2.9 lbs of boost (religiously) at wot with about 3 k.r. The BBv has already been bypassed so I know it's not that a few questions I have are how do I test the boost actuator? Is there anything else that can limit boost? (Car hits 2.9 almost immediately at acceleration but stays there) Any help is appreciated, and I'm sorry if I'm missing any important info new to the Grand Prix community.

Thank you
 


It's an aerospace interceptor but that may be possible it's as if the guage is limited to 2.9 before anything under 2.9 it seems to function regularly
 
Does it feel like its lacking? When I went on first drive with mine the solenoid was limiting me to 3 lbs, and I could definitely tell. Does the bbv move when you throttle it by hand?
 
It doesn't feel at all how it felt before but that's on the butt dunno. And yes the actuator moves when the car is reved. the plunger rests on th intake manifold while the car is off. The plunger is fully inserted at idle and when I rev it drops instantly about half of its full travel distance but comes right back up.
 
Smikey said:
It doesn't feel at all how it felt before but that's on the butt dunno. And yes the actuator moves when the car is reved. the plunger rests on th intake manifold while the car is off. The plunger is fully inserted at idle and when I rev it drops instantly about half of its full travel distance but comes right back up.
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"The plunger is fully inserted"... My mind=gutter.

But yeah, dunno man. Maybe belt is slipping? Just bypass it closed so you are in boost all the time and test it? Never tried but it should work. Least you'll eliminate the BBV.
 


how do you bypass it? is that the ziptie trick? i tryd that today with no change. at all zip tied open or closed i did notice it will spike to 3.2ish while the tranny is in between shifting not sure what that means
 
No I'm not scanning not at that point yet but looking into the process the car has a map wired in but I believe it's a 1 bar no markings on it except a 1k20 stamp? But it's small and square looks like a 1 bar map.
 
Yeah that's a 1 bar map. I could be mistaken here, but the aeroforce reads off the PCM, and the PCM uses the MAP sensor to read boost, if you hook a mechanical boost guage up I bet you'll see a lot more.

EDIT: Or, get a 2 bar map, and make the necessary pcm changes, and it'll show on the AF.
 


I do have one of these



i will install later today, but the car does have a custom dyno tune, could it be a running issue or computer issue?

Also purchasing a mechanical boost gauge today

Thank you again for everybody that's helping me this far
 
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You can't just install the 2 bar, you have to go into your map folder and change the max kpa so the pcm will read the higher values.

Edit: stick it on and see what happens actually, the pcm might be set up for the 2 bar, you'll know if it is or not when you compare the mechanical guage readings to what the AF says.
 
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