only making 20psi no matter what tune

No matter what tune its only showing 20psi max on the CTS. Does the cts show max boost or only what the map sees and if its programmed to only go so high will that affect it? If there was a 6.0 van turbo would it not make boost like a truck turbo? We checked for boost leaks and the IC was blown. Replaced it, no more leaks, and still only makes 20ps.

Garrett

No leaks and 20 PSI sounds like a possible VGT problem. How does your oil look?

Oil is fine, just changed some injectors then last week changed the oil cooler. He says it also runs the same on every tune from street to race, just more smoke. It was either on the canned performance or street tune today and seemed to run pretty good to me. Mind you, I haven't driven a stock sized tired truck with a tune in forever. Turbo lites right away, just peaks at 20 and pretty quickly too.

Garrett

Just a guess but the map sensor could be bad or as previously stated a vgt problem

I've heard of the CTS gauges maxing out before the actual boost came up, but I could have sworn it was higher than 20...

i was thinking it would be maxed at 26 or so but wasnt sure. what is the map voltage supposed to be? id give him mine but i dont know if mine works or not since ive always been analog. didnt use my commander to monitor boost either.

Garrett

Is this just flat footing it, or if you roll into it will it show more boost? Most of my race and extreme tunes run around 20 psi under full throttle, but if I'm in OD and roll into it, I can peg my 35psi gauge.

Even with a trailer and rolling into it so it doesn't downshift it still won't go past 20.

Garrett

Does the truck seem like it runs ok though, other than the reading on the gauge?

Yeah, like I said, I haven't rode in a stock-sized tired truck with a tune in it for a while(3+yrs) but it seems to get it pretty good. I've been spoiled with 500+hp trucks and my truck has been out for a while so I have nothing to compare it to. I'm just trying to figure out if its the edge or there is an actujal problem.