Well that didn't turn out like was planned

 

Im sending my injectors off to be cleaned and tested, to see if that was in fact the problem. Hopefully I will have the 5.3 back in this weekend.

Just my general theory.... something makes it past the fuel filter clogging the #8 injector, goes lean under boost and high rpm, causes detonation and melts piston, crankcase pressure goes out the wazzu because of that and dipstick blows out and forces oil through the exhaust to the turbo...the ac busting and blanket catching fire was a separate issue

 

who did ya get the injectors from? FIC?

 

The fire was probably the oil on the manifold catching. Just as you sometimes see transmitions over heating and they spew fluid out the dipstic. A big ball of flames and it goes out rather quickly.

Maybe this was your thery too but seems like what happened to me.

 

What about cylinders 5 and 7?

How do the other pistons look?

 

I've had these injectors for about a year without issues. I haven't pulled the other head, ill do that when I have the engine out.

 

Of course there was knock right before your fire, you just didn't hear it. I am interested in the results of the injector flow test, and I like 1slow01Z71's theory about too little ring gap. It seems that if rings have enough gap to put up with 20 psi, there is going to be a lot of blow-by, and customers don't like that in a brand new engine. But I have to re-question your knock sensor sensitivity, again using my reoccurring KR as a reference. In my mind, I would have not gone WOT at 20 psi again until I figured out why it was too lean (12.5 AFR) for safety, but in actuality I would do it anyway.
I don't mean to sound insensitive, I do feel your pain, having recently done a rebuild because of a wiped out cam.
I hope you do find the cause so you can put it back together and proceed with confidence.

 

According the the build sheet, top gap was at 0.024 and 2nd ring at 0.026. I never went WOT with the 20psi spring in there, I could tell it was overboosting with just 60% throttle so I drove it easy until I got the boost reference line hooked back up. The most boost I saw at WOT was 15lbs.

As far as knock pickup I never touched those settings, maybe my sensors need to be replaced anyway?

 

I guess we have different tables. I have four tables: three under "knock sensor level", and one called "knock sensor global gain". The higher the numbers, the less sensitive in mine. What does 65% mean? You multiplied the whole table by .65?
I am just focusing on knock sensitivity because you melted a piston and say there was no knock. Does that mean no knock retard, or no audible knock?

 

Both. No retard and no audible knock. Hell I drove it around the block with the hole in the piston and not so much as a code or vibration, just a ton of oil smoke.

I've already made up my mind I'm done modding this truck. Too much time, money, and effort to end up with no dd at the end of the day. Once I get the 5.3 back in I'm putting the sofest spring I can find in the wastegate until I find a stock ypipe to connect to the factory manifolds and the turbo is coming off.