put new DAP injectors in last summer. Have been fighting High EGTs and black smoke since. Didn't think +50 injectors would cause this much trouble. MAP 48 when pulling hard. Is  there ANYTHING in the VP44 that can make it overfuel with no codes? 

stock turbo

Still baffled by the lack of boost. 

 

Drive pressure leaks (crack manifold or blown exhaust gaskets)

Wastegate malfunction (wastegate rusted/stuck open)

Boost leaks...

 

Another dumb question? Do you have an exhaust brake? Is it stuck closed? This could produce seriously high EGT's and lack of boost pressure. 

 

The fact there is that much EGT's you've got the fuel but are you getting the drive pressure to the turbine to spin the compressor.

 

I've seen several photos floating around the Internet of turbos with broken shafts. Damaged turbine wheel or damaged compressor wheels.

 

Look for wheel damage. Chipped fins, rub marks where it's made contact.

 

Wastegate seen here.

 

It might be worth pulling that turbo to look at both sides. So you can inspect the wastegate and the turbine wheel. 

After boost leak repairs i am getting 25lbs of boost. Had the turbo off when I did the big exhaust and all seemed well.

Another stupid question. When you turn the switch on what does your EGT  gauge read? My tranny temp gauge is out of whack and sometimes reads 150+ * on a cold tranny. Cruising down the road empty it will show 210*. Yet I can still put my hand on the tranny. Just a thought.

Power on...cold engine...zero. Engine off, hot, pyro agrees with a temp gun taken at the probe

Waiting for my Quadzilla. I'm sure you guys will have plenty of help for me when I install it. Pulled the race trailer Friday eve. Made some REALLY hard pulls with it and each time the smoke cleared up a little bit more. Boost was up to 34 at one time. EGTs were still high but it would NOT peg the gauge. Easy question. When I let off the throttle too quick there is a loud, sharp, wooshing noise and my boost gauge bounces dramatically. I have heard that noise many time at the tractor pulls but never from this truck before. What is that noise?

It is called turbo bark. When let out fast under hard throttle the boost you are produce trys to go the other way since the engine can't use it. Very harsh on the turbo as understand it, trys to turn the turbo backwards. I am sure someone can explain better than me.

Thank you! I quickly learned to let off slowly?

42 minutes ago, dripley said:

It is called turbo bark. When let out fast under hard throttle the boost you are produce trys to go the other way since the engine can't use it. Very harsh on the turbo as understand it, trys to turn the turbo backwards. I am sure someone can explain better than me.

 

Close enough...

 

Dave is right. The boost pressure is built up in the air intake system and when you drop off the throttle the drive pressure drops away from the turbine. So now the pressure attempts to leave the manifold the easiest way it can by blowing back out the mouth of the turbo. Since there is no drive pressure on the turbine the boost pressure can spin the shaft backward as the air rushing out the mouth of the turbo. This is harsh on the turbo and possible to break the turbine shaft. 

 

Not a Holset turbo but you get the point...