I was looking at my boost gauge needle and it is shaking alot, while not in boost. But it shakes while getting into boost too and looks like it doesnt hold very well any more. Any ideas?

 

you need to tap into the f.p.r. vacuum hose.. that is the most stable vacuum source.. if you still have that problem buy a new gauge..

if the problem persists, search, there are some good threads on this subject..

my 03 did not shake, my 05 did till i moved to the f.p.r. line.

 

What type of gauge,stock?

 

oh sorry its a greddy gauge, but it just started doing it today

 

funny thing is mine is ding it too i have the defi bf's and i was wondering about it too. All of a sudden i wasnt able to boost past Wg pressure so I did a boost leak test and i was leaking from my hallman took it apart cleaned it up and i was able to hit 22psi again but I could still hear the leak from it. So I would suggest to make sure ur Bost controller is tight

 

Where were you leaking from your boost controller? I'm sure you know about the bleed hole, right? And you don't want to crank down those nipples too tight, or you'll ruin the gasket seals. Other than that, I doubt they would leak. Anyhow, a leaking boost conroller would cause overboost, not underboost. The air would be diverter away from sight of the WGA, therefore not opening like it should.

 

Unless you mean the mbc leaked from inlet to outlet where the ball and spring should be holding it if adjusted to the correct boost level.

 

yea know about the bleed hole but i think my boost controler seized up because as soon as i cleaned it t i was able to boost again

 

alright i'll check the mbc

 

why was your mbc hooked up during a boost leak test? it will leak...You should disconnect the lines to the mbc and plug them before the test

Also the needle on my gauge did the same and i had a really bad boost leak that was coming around my bov line at the nipple and it went away when i installed some nice silicone tubing, the rubber line just didnt hack it with the heat.

So your first step before replacing parts and checking to make sure your mbc is working correctly is to do a leak test and then go from there....

 

alright, i took apart the mbc and clea and tighten evrything and its working better and the needle doesnt shake anymore

 

i had my mbc set to 27lbs and it was working for a while btu lately my gauge is only showing like 20-23psi and im wondering whats wrong ... whats the f.p.r. ? im using the vaccum line that comes from the intake manifold i have both the boost gauge and smc controller hooked to that line

thanx

 

What's the advantage of hooking up to the FPR line?