boost gauge issues

[hellraiser456]

So i tried searching and nothing really applied to my issues...and i tried googling for a bit but that didn't go so well ether.

I installed a boost gauge to me car today and it is all over the place.

when i start the car it will remain at 0psi and only pull a vacuum while driving...no more than -10 vacuum. No i know i have a boost leak and am aware of that. under boost it will goto about 5 psi and then when i let of the gas(right off) it will drop to 0psi then jump to 5 and then slowly go back to zero

My conclusion is that my bov is messed. Now my boost leak is from cracked hoses to the BOV and from. I have a new assembly on the way...but im just wondering if it would just be the BOV not doing its job. and causing the weird issues...or i hooked my boost gauge in the wrong place.

It is hooked to he hose that goes to the bov.... It is spliced about midway in between the intake and the hard pipe that leads to the BOV. is there a better place i can hook it up?

 

[Spiv]

It should be hooked up to a source off the intake manifold, as in between the throttle body and the engine itself. Everything else is prone to surge a little (as you're seeing on the gauge), is no idication of what vacuum is being pulled, and doesn't represent what's going to the engine. Basically where you hooked it up, I would expect it to sit at or around zero vacuum until you mash the throttle- go a little negetive, then boost up when the turbo spools. No suprises there.

To know what's going on in the pipes, you can tell by the sound. The stock BPV(BOV that vents back into the system) shouldn't allow the turbo to surge much at all (sounds like the turbo 'stutters'), but likewise it shouldn't be stuck open or anything. If you suspect your BOV is going bad, pull it out and test it (I think there's a good procedure in the manual). In short you put a hand vacuum pump on the vacuum nipple and start pumping till it opens- too little pressure or too much pressure to make it actuate is a bad sign, or one that won't seat/seal without vacuum is no good either.

Fix your known boost leaks, sometimes it can be hard to tell if other things are going on when you've got issues like that masking them, especially right near the BPV/BOV. That and plug the vacuum line into somewhere behind the throttle body, and you should see what's really going on.

 

[futeki_supra]

yea you have it hooked up incorrectly,

find the vac. source for your stock boost gauge,
( small box with a vac. line going in one side and wire coming out the other )
right by the DS shock tower

 

[hellraiser456]

wicked found it and got it working...thanks guys