No/low boost

bigfords · Mar 25, 2013

I took a look at a friends 05 6.0 last weekend. He said the truck was only making 15psi of boost. I figured he was just overlooking an intercooler boot or leaking up pipe.
There are no leaks anywhere...he put all new intercooler boots on. There is zero black soot around up-pipes and no leaks. When driving the truck, it will only build maybe 10 psi of boost if you are lucky. The exhaust does sound different, and the noise seems like it is coming out of the exhaust (not up-pipes).

Any help? I am really leaning towards some kind of turbo failure...I really don't think it is the vanes sticking or anything. It is an all-the-time problem, it just won't build boost!

thanks!

svilla · Mar 25, 2013

Is his exhaust stock? in other words does he still have the cat? Maybe disconnect the cat and take it for a test drive. I have never heard of one failing on a diesel truck, but you never know.

bigfords · Mar 26, 2013

That is a possibility...I'll have to check into it. I do think we found the problem though, we pulled the turbo apart and it looks like the ring and vanes are seized up. It must be stuck in the open position. I just didn't think that even in the open position that it would dump so much boost! I thought fully open would still net a big boost number...I guess not.

MUDSTROKIN' · Mar 26, 2013

Veins are most likely stuck. Clean them and the ring real good and clean the posts with sand paper or emory cloth reassemble and viola

Gary · Mar 27, 2013

You said the exhaust sounds different, so I'f check for a exhaust leak at the Y to turbo, up pipes and bellows.

Andrew · Mar 27, 2013

I would start by checking the ebp sensor and tube make sure it's not blocked. Then dies the exhaust change tone at all while the truck idles ? If it does the veins are not stuck if not they are stuck. If it is the same tone all the time you need to pull the turbo and clean the veins and unison ring. If the oval hole on the ring is egged out at all the ring should be replaced. Coat the ring and contact sides of the veins in a thin layer of nickel based antisieze and reassemble.

jdeeg4276 · Mar 27, 2013

same with mine just no boost.

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bigfords · Mar 30, 2013

Well we got the turbo all cleaned up and reinstalled...still the same problem! I told him to unbolt the cat and drive it again...sure enough it ran like a champ! I haven't seen it before on a diesel yet..but I guess the cat is plugged. At least we now have a functioning VGT turbo