Need help COMPOUND TURBO EGT'S

[chadmax]

I bought a 2008 dmax back in may. When I bought the truck it ran consistent high 12's low 13's and my EGT'S usually ran around 1400-1450 degrees at WOT on stage 5 dsp. Now it feels sluggish all of a sudden. My injection rates are normal and it runs smooth but I'm now running 14's in the quarter and my EGT'S are running up to 1700 degrees before it goes into reduced power mode (if I don't let off or dial the EFI live back). Air filter is clean and I have already checked for boost leaks. It has done this with several tanks of fuel and also after filter change. What else would cause it to do this out of the blue? It is a mildly built duramax with a compound s475 over stock turbo setup with stock rod, stock injectors, and stock intercooler.

 

[chadmax]

This is what the truck has in it

 

[mike diesel]

You need to data log it. Scan for codes also.

 

[N2BRK]

how's trans temps?

 

[NC-smokinlmm]

Maybe bad boost sensor, the ECM will command maximum vane postion if it dosen't see a boost reference number. That would make for some toasty EGT's...

 

[JoshH]

What code is putting it into reduced power mode?

 

[zf>allison]

Fuel filter?

Ah I see now he changed it thought he was talking about the air filter when he said he changed It.

 

[chadmax]

It's not showing a code when it goes to reduced power. It just goes reduced and stays there until I restart the truck while going down the road and everything is back to normal. My Trans temp is good.

 

[plowboy_lbz]

Lift pump?

 

[chadmax]

It has a brand new air dog on it with a fresh filter change

 

[Bonestock]

How did you test for boost leaks? The factory y bridge on Lmm are prone to blowing the orings which will give you the exact problem you are describing. Just to make sure if you can un hook compressor side intercooler pipe and hook up a boost test grommet and put a regulated 40-50 psi on it. You will hear / feel if its leaking @ bridge. I know you said you tested just make sure cause I have seen this many times.

 

[Bonestock]

I have a welded y bridge if you wind up needing it.

 

[hondarider552]

holy shit 40-50psi will blow the test cap across the street and hit the neighbors kit on his tricycle...

FWIW I found a lot of leaks as low as 10psi.

 

[Cknight199]

holy shit 40-50psi will blow the test cap across the street and hit the neighbors kit on his tricycle...



FWIW I found a lot of leaks as low as 10psi.

I've been at 75 psi and it was scary lol. It gets unnerving when you watch all the silicone boots expand HA. That being said, I found all the leaks I had at 10 psi like Brian said. I just wanted a pic with my boost gauge pegged

 

[blitzin247]

Brian you always make me laugh! :hug::spit:

 

[Bonestock]

holy shit 40-50psi will blow the test cap across the street and hit the neighbors kit on his tricycle...

FWIW I found a lot of leaks as low as 10psi.

Lol never had an issue @ 40-50 psi. Actually required that for my def ass to hear. I could see if there were not any leaks but hell compound trucks run by 40-50 all day.

 

[S Phinney]

That is why you use lower pressures and spray it with soapy water. I found way too many leaks on place that you would never expect with the water. Things you could not feel or hear that were really bad.

 

[clrussell]

Does it come up and say change fuel filter everytime you run it hard and you have to reset it?

 

[Harbin_22]

I had a leak that would only leak at 10#'s or lower.

 

[danzick]

I cant image testing with that kind of PSI. I would test mine around 22 and the rubber boots were already rock hard at that point!