I was messing with it one day cause i was boosting at over 25psi. I then tried to adjust it back to 21 and now it wont go over 16 - 18 psi on any gear pull..The MBC knob is turned all the way out...what can be the problem...?

 

Check for a boost leak which may have developed after you over boosted

Also - as a way to diagnose the MBC - pintch the line to the MBC closed shut and watch in 2nd gear of the boost spikes up higher - just let it shoot up qucik do not hold a high boost

 

Something is messed up if it's all the way out and is 16-18psi. It should be at the minimum of 11psi if it's all the way out. When you turn it all the way IN, it will go to max boost.

 

lol thats the reason...i thought it was all the wayout for max boost..i will try that and see what it does

 

to let you guys know when al tuned my car he found a boost leak..but the car has been holding 21 psi good...no problems..

 

Doesn't your MBC have arrows on it with a plus and minus sign showing which way to turn it?

Again, if it's all the way OUT, it should only show 11psi. There's no way it can show 16-18psi when set to minimum boost, so that's another issue.

 

all the way out it was showing 13-14 psi...that 16-18 was in a a little bit..then I turned it all the way in and the turn it out a little..spiked it to 28 - 30spi...just made some adjustments pulling it out..got it holding 21 psi again steady

 

Ok, well that was easy. Glad I noticed your slight mistake. I wouldn't have recommended turning it all the way in like that...try turning it up steadily next time. You don't want to spike to 30psi on pump gas.

 

yeah i was worried...i havent gotten the boost leak fixed and i was worried that was causing the problem like it got worse