On my Scan Gauge I am only seeing 19lb of boost max under WOT. I have removed all the hot and cold side boots and inspected for leaks and they were all good. Looking at VGT readings they are around 68 at ideal and around 35-38 at WOT. I have also notice that while is park at idle it is sweeping the vains as it goes from 84-0 then back to around 68. ICP reading are also in spec as I had read that could be the problem.

I will add that the truck is running great and had I seen the boost number I would have never thought anything was wrong. From reading the forum it seem most are in the 25-28lb range at WOT. Any ideas or maybe just the way my truck is?

 

I will also add the before I had the truck on 5/30/12 the turbo had the unison ring and VGT valve replaced. I have the Invoice and those were the only 2 parts listed plus the 4 hours of labor.

 

Sounds like you don't have the SG2 programmed correctly for your altitude.

Josh

 

Check codes in scan gauge and they are all correct for altitude and boost. Actually found a different one than I had in there originally and changed it (Bismic listed it). Took it for a spin and only got up to 17.9lb WOT.

 

Ok, did the VGT reset procedure and then test drove. No change saw 18... lb. Pulled MAP hose and sensor and it was free and clear no clogs or debris(read that might cause and issue).

Out of ideas at this point.

 

Exhaust leak? Mine's leaking pretty bad around the manifold to head and I'm getting 20-21 maximum.

 

I checked that. Found nothing

Could it be a dirty EGR valve stuck open and bleeding off boost? IF that was the case wouldn't throw a code of some kind?

 

Pulled egr valve and it was dirty but there would be no issue with function. Pulled the exhaust back pressure sensor and cleaned out the passage. It was all clear and appeared to not have any issues. Still seeing low boost. I am out of ideas at this point.

 

Do you have a fuel pressure gauge or have you updated to the blue spring?

 

Do not have a fuel pressure gauge but do have the blue spring installed. Fuel filters are relatively new but this condition has always been present just finally realized it was not correct.

 

03 relies on BARO and MAP and MAF for turbo calibration

Post BARO & MAP at KOEO low idel and high idel (2500rpm)

then Put it in 3rd Gear and go WOT this will Load Engine It and see what you get for Boost

 

First thanks for the help. I am stumped.

BMP 14.7 KOEO
MAP 14.4 KOEO

BMP 14.7 LI
MAP 14.3 LI

BMP 14.7 HI
MAP 15.0 HI

BMP 14.7 WOT
MAP 30.1 WOT
Max Boost seen 16.3lb WOT 3rd gear

 

Could a dusted turbo or clogged air filter be the problem? I've heard that someone had a birds or rats nest in the intake of the filter. Just a long shot guess.

 

Had that all apart as recently as last night. The air filter is good acording to the gauge.

 

Well it looks like the Map and Baro sensors are Good


Post the Boost Code you are using for the SGII



When you checked for leaks did you check the Exhaust Uppipes from the exhaust manafold all the way to the Turbo??????

I would check when truck is Cold By starting the truck and then feel around each exhaust joint and the Flex joints and see if you can feel air blowing out the uppipes
The flex joint is a Common spot to develope a Leak

Also sprat CAC Boots with soapy water and check for Bubbles at Idel