help! 04 6.0 has me stumped

speedracer1000 · Nov 3, 2012

got a 04 6.0 with high miles that i just did hg's studs, egr delete, the whole 9 yards. never drove the truck before we did the work my buddy bought it and i just towed it to the shop, had a blown oil cooler didnt wanna drive it too much. anyways i did all the work got it runnin took it for a ride, has no power under load and coughs back through the intake like its over boosting, which it is, has plenty of boost but i keep getting a code for turbocharger underboost and exhaust pressure sensor. so i try loading a steet strategy tune to see if it changes anything, and it doesnt, so i check the usual connections, maf, ebp, vgt, ect. but i notice that when i first started the truck i could hear the vgt cycling and now i cant, it just doesnt sound right while driving, also i have a snap on modis scan tool, and i can command vgt duty cycle from 0-85% and when i do that none of the values, ebp, map, ect doesnt change. so at this point it looks the turbo is sticking. but if so y no power? its got all kinds of boost so you would think it would have plenty of power still, so does the pcm defuel in the event the turbo vgt doesnt work?

Derek@Vision Diesel · Nov 3, 2012

speedracer1000 said:
got a 04 6.0 with high miles that i just did hg's studs, egr delete, the whole 9 yards. never drove the truck before we did the work my buddy bought it and i just towed it to the shop, had a blown oil cooler didnt wanna drive it too much. anyways i did all the work got it runnin took it for a ride, has no power under load and coughs back through the intake like its over boosting, which it is, has plenty of boost but i keep getting a code for turbocharger underboost and exhaust pressure sensor. so i try loading a steet strategy tune to see if it changes anything, and it doesnt, so i check the usual connections, maf, ebp, vgt, ect. but i notice that when i first started the truck i could hear the vgt cycling and now i cant, it just doesnt sound right while driving, also i have a snap on modis scan tool, and i can command vgt duty cycle from 0-85% and when i do that none of the values, ebp, map, ect doesnt change. so at this point it looks the turbo is sticking. but if so y no power? its got all kinds of boost so you would think it would have plenty of power still, so does the pcm defuel in the event the turbo vgt doesnt work?

Well if the vanes are stuck closed it spool great but build all sorts of back pressure and "choke" itself to put it simply.

Sure the vgt actuator is actually doing its job?

Sent from my DROID BIONIC using Tapatalk 2

hawgdoctor · Nov 4, 2012

Don't know what strategy code it has, but is the ebp sensor, and tube clear? Vgt plugged in good? Unplug the vgt, abd see if it changes pitch in the exhaust too. Map hose clear? Lots of little things......

sent from the shop making things fly.....

speedracer1000 · Nov 4, 2012

derek that makes perfect sense tt me now, almost acts like thats wuts goin on, how do u test it to see if the vanes are stuck or if its the actuator? is there a way i can bench test the actuator?... i will also pull the ebp and tube off and check that out, wost case scenario ill pull the ebp off my truck and put on it jus to try it u guess

Gary · Nov 5, 2012

Sound like classic VGT veins/unison ring sticking, if so you need to take apart the turbo and clean it up. It will probably have P0299 code

speedracer1000 · Nov 6, 2012

will be pulling the turbo apart this evening and checkin it out. i unplugged the vgt solenoid while running and nothing happened or changed. im thinkin thats where my issue lies