Very loud under load

Well so far you guys have pretty much solved every problem that myself and my shop couldn't so I'll go back to the well one more time!!!

Unit: 1997 Western Star with a 3406E

Problems: VERY underpowered, and consuming more fuel. VERY VERY loud when the manifold pressure (according to the gauge on the dash) goes anything over 15. By 30 you can't even stand it anymore. It sounds like you are right beside a jet engine as it winds up.


What it is not:
air to air. The air to air is neither plugged nor leaking. We have pressurized and sprayed it. We actually changed it at first because the old one had a few bubble leaks and we though maybe they were enough to be causing our problem.

Any kind of exhaust leak: checked the whole thing, and it's excellent.

We have also sprayed along the whole air to air system at places like clamps and all the hoses etc and can't seem to see a leak but in the shop (and even outside) we can't get the manifold pressure high enough to really do a propper test. I can't really have a guy stand in the engine compartment while we fly down the road loaded so I'm too sure what step to take next.


Could it be the turbo? If so how do I diagnose that?

Any ideas or diagnostic help would be appreciated. The only shop here that can work on these says it is 2 weeks before they can get to it, and I can't wait that long.


Oh there is one more thing worth mentioning. When we start the truck it runs like garbage for about 30 seconds and smokes like crazy. Also if you leave it on low idle for say 2 minutes and then floor it, it burns very blue for 30 seconds or so and won't accellerate past about 1500 until the excess fuel burns off. I am assuming that it is unrelated injector leaking issue since I've seen that before (I plan on fixing that while it is in at the same time) I only mention it in case someone thinks the two could be related.

Thanks in advance.

 

OK I checked all of the above and didn't find anything BUT I discovered the waste gate was stuck in the almost completely shut position. Would that be the problem perhaps?

Fuel pressure is great and steady but I'm sure I have a leaky injector soemwhere we'll dig into that next.

 

I took both "covers" off. I see some slight makings on the intake wheel right on the face of the blades but I don't see where it is hitting the sides at all. There is no real play in the bearings either.

 

Dyno? I'm lucky if I can find someone around here that carries fuses.

No I wish I had somewhere with better diagnosics or else another dealer I could go to. I like my Peterbilt shop but they are always heavily overbooked and I can't wait 2 weeks to get it looked at.

Back to that faulty waste gate. I had to pry the living daylights out of it to get it to open and now it opens with the expected amount of pressure. If it was closed all the way though I would think I would have MORE power than less correct? Maybe I have 2 problems.

Would the closed gate be the cause of that insane whistle I'm hearing under load?

 

Part of the frustration is that I don't know. You can only hear it under load and so you can only hear it from the drivers seat and from there it is so loud I have no clue which side it is from. If I had to guess I'd say Turbo side but that's a guess.