Boost!?

[Moriarity81]

Alright i think i posted a thread b4 about this but i just bought my gtp its a 98 and my pillar guages the boost was only reading 0 when i floored it and the vac was like 20 at an idle? Well come to find out it was hooked up wrong so i went to auto zone and installed a new t for the boost guage and everything now at an idle the vac. Is about 10psi and holding the throttle wide open going down the road the most i can get is about 3or 4 psi of boost? I was told it should be reading about 7 or 8psi? How do i fix this? Also the stock boost guage go's about half way maybe a notch past half but no more so i think somethings up.

[txslow6]

Check you lines to the BBV sounds almost like the sensor came unplugged. Where did you t for your boost gauge?

[Moriarity81]

I have no idea what a bbv is or where it woukd be lol i was told where to hook it up and thats infront of the motor there is a T on the fron of the suppercharger to the left that has a line running from under the s/c cone and the t is pluged into a little nipple thing then another line runs from the t maybe 8" to the right then plugs into another nipple thing i hooked the new t between the old t and the last nipple thing.

[blueguy]

That's why...it needs to be "T"d in after the LIM and before the MAP sensor on the back of the supercharger.

[Moriarity81]

what exactly does the lim and map sessor look like? i hooked it up behind the supercharger and still only get 3 psi lol

[Juanmiguel]

conect it to the vacuum line that goes under the supercharger snout (the end with the pulley and belt).

[SDGTP99]

Google a vacuum line diagram.

[Moriarity81]

thats where its connected yet im still only getting 3psi of boost max and about 18-20psi of vac. when im at an idle

[01gpgt01]

Sounds like the BBV valve isnt closing the whole way

[Moriarity81]

what exactly is a bbv valve? whats it do and wheres it located so i can check it out

[KeithGTP03]

This is the bbv


And this is the shaft the opens and closes it. Use your hand and see if you can move it up and down.

[Moriarity81]

yes i can move that but at idle its all the way up and when i hit the throttle it opens and goes all the way down.

[matt5112]

was the car modified when you bought it?

[Moriarity81]

nothing major its got a aftermarket intake and i believe its programed bc its alowed to rev to 5g's in park and neutral but other than that nothing else i know of

[Scottydoggs]

1998's dont have a rev limiter.

[Moriarity81]

well that dosent help me either way bc even while going down the road i cant push any more than 3 psi and the stock boost guage on the dash only goes about half way. what i was told is it should read around 7-8 lbs of boost when its to the floor

[dsmuts]

1998's dont have a rev limiter.

Yes they do

To the op: you most likely have a vacuum leak somewhere, spray some carb cleaner or starting fluid around the motor until you hear a difference in the idle and where you sprayed it is your vacuum leak.

[matt5112]

how do the vacuum fittings look? Vacuum level suggests no vacuum leaks, but its still very possible.

Pull off the rubber connectors and see if they fall apart.

If you have access to another car or a ride to the parts store that is.

[Scottydoggs]

Yes they do

mine dont, i could floor it till it blew up, in park.

[matt5112]

mine dont, i could floor it till it blew up, in park.

to 6000 rpm?