I'm begining to believe that my waste gate is opening and the gasses are melting the insulation on the (is it the firewall?) firewall between the engine compartment and the cab. The insulation is clearly being 'melted'/blown away vs. torn away, as a few plastic parts around the missing insulation show signs of melting too. Is it the waste gate releasing gasses or might it be something else?

Perhaps related, while towing a 14K lb trailer up grades I can, rather easily, set off the check engine indicator. This has happened ~8 times and each time (except once) the indicator light will reset itself the next morning. The one time that it didn't reset I took the truck into a local GM shop - not a dealer. They said that they "couldn't tell for sure but thought it was something to do with the waste gate".

The only mod I have on the truck is a Juice/Attitude, towing in level 2. Max boast shows only 22.

Any ideas?

Hard to say but it sounds like the waste gate may be stuck or not seating properly or an actuator problem. It should show up at a high boost (WOT) run. You should be seeing around 26 PSI @ WOT with the stock turbo.

The wastegate bypasses exhaust gasses withing the turbo housing - no exhaust is vented to the atmosphere. Do you have a pre turbo EGT? Sounds like the turbo housing is hot enough that the heat shielding can't protect the insulation.

Sounds like your turbo is getting HOT!! I had split plastic loom tied to the A/C line running over my turbo and it melted it like a hot knife through butter. Keep in mind that this is at least 8 inches above the turbo!

Get a pyrometer if you don't already have one!!!!

I do have a pyro. The sensor is tapped into the manifold and connected to the Attitude. Max on EGT shows 1360 (high I know) but that would have been a spike. I don't let it run over 1300 up a grade.

I had the heat over the turbo melt the wire loom on my pyro wire and boost pressure tubes. I've since tied them off to the top of the AC hose running over the turbo heat shield. It looks like the turbo can produce some pretty high heat levels in that area in spite of the installed heat shield.

Unrelated to the heat you're seeing but if you run enough load to see + 1300 your engine should be seeing more than 22 PSI manifold pressure.....

Unrelated to the heat you're seeing but if you run enough load to see + 1300 your engine should be seeing more than 22 PSI manifold pressure.....
Was thinking the same so I've reset the record of the boost and also set an alert if the boost goes over 21. That way it shoudl call my attention to it as it goes above.

It is probably just your turbo getting that hot. After I got my turbo replaced they must have got some oil on that insulation and at my next pull it actually started the insulation on fire. Melted my pyro wire some and burned some insulation off, it went right out but that is pretty darn hot to do that.

At 6000' of altitude, or more, I run hotter EGT and max boost will actually fall below 20 psi. Boost is as read by the ECM.

Didn't know altitude would have such a large impact as I live about 12 feet above sea level and see around 27+ boost on hard pulls with about 1300 EGT. Amazing enough though. Or maybe it's my waste gate thats not working/opening. :confused:

When I get down to Dallas/Fort Worth or into California, I see 26 psi and have a hard time getting EGT over 1050. I was shocked when I saw that the first time, but it is absolutely the same every time. I guess lack of air density is the issue.

I could fashion an additional heat sheld. Is there any reason that I shouldn't do that?