yeah do a boost leak test and see what you find.

 

The harness might be the problem, and that's why none of us have had the problem it's a new harness.

 

yeah it could be a stg1 issue. i have had the same symptoms with a boost leak....couple lbs short of what you should be boosting and crappy gas mileage.

i would do a boost leak test first....rule it out if anything. it only takes like 5 minutes and if that isn't it then you can dive into all the stage 1 bullsh*t

 

How do I do a boost leak test? I have seen them for sale but I don't know the proper size to buy or where to install it for testing.

 

2.5" or you can make one. you can do it from two different places....first from the intake inlet of the turbo. take off the stock intake and pipe that run to the turbo and connect the tester to the turbo inlet. pressurize the system to 6-7 psi....DO NOT GO OVER THIS OR YOU RISK DAMAGE TO THE TURBO!!!!!....and spray soapy water all over the intake area where you attached the tester, all over the charge piping hot side and cold side and over the intercooler end tanks and inlet/outlets. if air is leaking the soapy water will bubble up as the air escapes. some boost leak testers come with a pressure guage so if air is leaking the pressure will go down on the guage.

the second way to do it is to disconnect the hotside piping from the turbo and connect the tester to the hotside pipe. if you buy one then you more than likely need to do it the first way or make an adapter out of pvc piping (a tester that you buy will come with a coupler that you clamp to a pipe.....in the second way with the stock charge piping you would be attaching a coupler to a coupler which obviously wont work so a piece of pvc is needed to connect properly. now in this way you pressurize the system again but so much care isn't needed in how much psi you go...here you could do 20psi or so. now same deal spray with soapy water and watch for bubbles.

 

Pimphand.....I am having the same issue. I've checked everything so now I'm waiting on ic piping to see if that cures my low boost issue.

Also I've been thinking that the ones who claim they are getting 22-24psi may have the pillar mount boost gauge. I have the rpd which is electronic. So my question is....are some of you seeing 20-24 psi on the rpd display ( with Gmstg1). I am thinking it may b just because of the gauge itself.

 

the rpd and the autometer guage are both electronic and get their reading from the ecu so i don't know if one would differ from the other.

 

There is more you have to do than just pressurize the system. I did this and ended up having oil pushed into the exhaust and took a while to burn it all out. Have you do.e this yourself?

 

i am assuming that you used the first option i described. if oil went in the exhaust too much pressure was used and pushed oil out the turbo seals. that is why you should only do 6 maybe 7psi

 

Yep ur right I did go directly onto the tubo inlet. I thought I effed my car up when I started it and it filled my garage wit smoke.
The second problem I ran into while testing for boost leak was once I got to about 10-15 psi, air started coming out oil fill cap.