I've searched

[phil_long]

I've been looking for explanations for my issue, but have yet to find one.  I havent touched anything(settings, etc) within my chip.  During all my testing and tuning the car ran great.  It still runs good, but if i stand on it from a dead stop, the car only makes approximately 12 lbs of boost or so.  When i ease into, it might make about 15 lbs, but if i push all the way down to the floor during the "easing into it' it drops back down to about 12 lbs or so.  Pissing me off seeing that I haven't been tampering with anything.  Thanks for any advice or suggestions.  I have intentions to buy a billet vacuum block too, because I like the way they look, and I'm eliminating any possibilites of leaks. 

[Steve Wood]

are you using the stock wastegate solenoid?  If so, pull the hose off, step on the gas and, if the boost shoots up, take your foot off the gas instantly before the boost gets too high.

[phil_long]

I suppose I am.  Lol.  Everything is stock to my knowledge.  I'll take a look and see if i can find that hose you're referring to.  Should be the only hose running to the wastegate puck right?  Correct if wrong. Thanks

[earlbrown]

There's actually three hoses....     and you NEED to replace them yesterday!!!   Those little things can send your head gaskets into the stratosphere when they get old enough.


There's one hose that runs from the compressor housing to a plastic wye fitting.  From there you have a hose that runs to the wastegate and one that runs to the boost control solenoid.   The science behind the circuit is two fold....

 Boost pressure opens the wastegate to dump exhaust energy around the turbo.  As the boost comes up the wastegate opens proportionally to slowly vent boost until you're at full pressure and the wastegate has found it's 'happy place' (hi-tech engineering term)

The solenoid acts as a 'signal dump' and holds the wastegate closed (or at least more closed-er) until the last second then lets it fling to it's happy place.  The benefit is you put more exhaust energy into the turbo during spool up.

The other is that it allows the ECM to vent signal and raise the manifold pressure above the wastegates spring tension.


Notice during spool up, the solenoid is in dump mode. After that, it drops down to a preset PWM signal. 

If it were me trying to shake down that system, the first thing I would do is run a brand new hose between the compressor and the wastegate.  (search term: "tuner style". Don't forget to safetywire or ziptie the ends) and see what the boost does.  Then reintroduce solenoid circuit and observe the changes to boost levels and spool up speed.

[earlbrown]

Oh yeah, the rule of thumb with vacuum hoses is.....    If you rub the hose and your finger turns black...  replace it yesterday!!


Never a bad idea to blow/suck through the check valves too.  giggity.

[Steve Wood]

the hose that connects to the wastegate solenoid...tho ught I said that

guess the translation did not come out right 

[phil_long]

I'll check the hoses and their condition. I thought they were ok when i visually inspected them, but it was all visual.  Im sure black will come off of them seeing that the turbo is passing oil and its a bit messy around there.  Lol.  And, from what im reading, only one of the hoses will be connected?

[earlbrown]

Yes. Run one piece of new hose from the turbo compressor's brass outlet to the wastegate.

Then see what your boost is and how fast it spools up.

[earlbrown]

the hose that connects to the wastegate solenoid...tho ught I said that

guess the translation did not come out right 

Your method is scary and I wanted to use pictures! And through out some solenoid tech while I was at it

orrrrrrrr.....    I was on the couch with the Buick's laptop and did feel like getting out from under the covers!   (it's one of those two )

[Steve Wood]

nothing scary about it...if the boost goes past the 12-15 psi point, take your foot off the gas....

then either find another solenoid or put a manual controller on it.

If it does not go up as it should, then we look for something else

[phil_long]

Makes sense.  I'll check it out.  Unplug the hose that runs to the solenoid. Floor it, hopefully it goes to 17lbs. 

[Steve Wood]

Stop, you did not read what I wrote!  It might go to 30 psi because there is nothing left to control the boost!!!!!!!!!!!!!!!!!!

I said take your foot off the gas immediately if the boost goes beyond 15 psi!!!!!

[earlbrown]

Stop, you did not read what I wrote!  It might go to 30 psi because there is nothing left to control the boost!!!!!!!!!!!!!!!!!!

I said take your foot off the gas immediately if the boost goes beyond 15 psi!!!!!

told you it was scary

[Steve Wood]

LOL...only if one does not follow instructions!  If people would only take the time to understand how stuff works instead of googling for similar problems, it would be a lot easier!

[TURBOPOWERED68]

LOL...only if one does not follow instructions!  If people would only take the time to understand how stuff works instead of googling for similar problems, it would be a lot easier!

A lot easier--YES
But less Fun.