I did a full delete(egr,cooler, throttle valve) about 5mos ago and have been chasing a boost leak ever since. No noticible loss of power, sounds like it's on the positive side. Louder in the cab than the engine bay. Service air filter has been going off but it only has 10k miles on it. I'm going to be making a 5k trip soon with 2 vehicles in tow and I'd really like to get it figured out before then. Ive taken everything apart one time and put it back together.

 

Just keep looking. Look at everything that you messes with. Obviously everything on the pressure side of the air path

 

Can you cap off these turbos and pressurize the system like the non vgt's?

 

I capped off the turbo and pressurized the system(probably more than I should have) and could not get it to make the sound.

 

My guess is it's not a boost leak but an exhaust leak at the rear cooler block off plate.

 

That would make sense in this situation. It's been a while since I've checked it so I'll look into it.

 

Might see soot seepage at the back plate. Back the bolts off slightly then retighten.

 

It's not the block off plate. Definetly seems like it's coming from the positive side towards the back of the engine. What could possibly be leaking back there?? Again, it only does it when it starts building boost. I'm getting desperate and asking around for shop suggestions. Heading out next wk for a cross country trip.

 

Try installing an extra washer under the nut on the rear block off plate stud closest to the engine block. On a couple of engines I've found that the stud is not threaded into the block far enough and the nut goes thread bound, so the nut is tight as it's run out of thread on the stud so it's not pulling down the block off plate far enough, it's close but not close enough.

 

Wouldn't there be soot marks if that was leaking? On the plate or the gasket?

 

yes there would be if it was leaking all the time but like I said it's very close to being sealed all the time but under acceleration it opens slightly and if the gasket was any other than metal it probably would blow the gasket. I'm not saying 100% sure that's the problem but there is no cost to it and now the cooler is gone it's fairly easy to get to.

 

I wish that would've worked but it's still there. I'm not sure if this is related or not but I've recently lost 4-5mpg. I put on new tires an inch and a half taller and a new air filter but I wouldn't expect that much of a drop just from that.

 

That's too bad it didn't fix it for you. I'm sure you reused the metal gasket with the block off plate? Did you do the CCV delete? If so did you use a clamp on the plug? Did you replace the down pipe or keep the factory one, if you replaced it could the exhaust be leaking at the turbo.

 

Had a nightmare experience with a shop but it's fixed now. Apparently there were a couple small pieces of gasket material left on the intake horn where the throttle valve meets and that's where it was leaking. Thanks for help!

 

That's good you found the problem, we replaced the entire intake horn with an after market one so no need to take off the valve.