booooost

[YZ250rider]

So, I've had my '98 GTP for about 3 weeks now, and I was wondering about my stock boost gauge. When I step on it, the gauge only goes to about half way. Is this normal? or should I be concerned with something being wrong?

 

[Iceman6669]

It will only go half way when you FLOOR it and hold it there??

 

[YZ250rider]

Yeah

 

[Iceman6669]

Then yes something is prolly wrong. I mean it could just be the lights are burnt out.. BUT it sounds like you have a VAC leak or your BBV is not working right. You are doing this in DRIVE not in Park right.

 

[YZ250rider]

Yes. This is as I'm either driving or going from a complete stop

 

[Iceman6669]

Ok. Just wanted to make sure.. I would start by looking for a vac leak.

 

[YZ250rider]

I just looked and the vac line under the supercharger looked like it wasn't broken or leaking anything.

 

[Iceman6669]

The best way to check is to have the motor running and spray carb cleaner or starting fluid on the vac lines. IF you have a leak you will hear the RPMs spike.

 

[YZ250rider]

just sprayed carb cleaner on the vac line under the s/c and the other t-fitting and rpms stayed the same

 

[fri3dchick3n]

How about your SC belt, is it squeaking any? If it is, replace it.

 

[Iceman6669]

Did you do ALL the vac lines??? Including the one that runs from under the snout to the MAP sensor on the back of the motor?

 

[YZ250rider]

just sprayed all three and there was no rpm rise. if my belt is squeeking then i cannot really hear it.

 

[Iceman6669]

sounds to me like your BBV or your BBV solenoid is bad

 

[YZ250rider]

What is that and what can i do to check?

 

[BoostenGTP]

Unplug the boost bypass valve, its in front of the throttle body. Unhook the wire harness from it and see what happens. If you get full boost back, the BBV is shot, just unhook it, you don't need it. Drive the car, see what happens.

 

[BoostenGTP]

Here I made a diagram for you.

remove the RED painted vacuum line, just remove that T and hook it up to the top of the fuel rail there. The Blue circle is the electrical plug for the bypass valve, its under that harness. Just remove it. The green is the boost bypass valve, just unplug the red vac line from that, let it stay open on the BBV plug, don't cap it off. I had the same issue and THIS fixed it. Hope this helps.

 

[YZ250rider]

which one is it?

 

[YZ250rider]

so can you color me a picture of where the vac line goes and exactly which harness to pull?

 

[BoostenGTP]

I did... the red vac line goes BYE BYE, same with the Vac T on the fuel lines, just hook it into the fuel rail. Just look under your hood and you'll see what i'm talking about. behind that harness there is an electrical plug for the boost bypass valve.

 

[silvermistgt2002]

so can you color me a picture of where the vac line goes and exactly which harness to pull?

you sir...are a retard.