Turbo/boost or ecm issue

WVRigrat05

Wound for sound
Jan 1, 2011
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French Creek, West Virginia
Trucks done, runs and sounds good, but... at 1500 rpms in all tunes the turbo canes are shutting all the way and making way too much boost, if you hold it at 1500 rpms it comes and goes like its doing a vane sweep, I’m stumped.
 

Chevy1925

don't know sh!t about IFS
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Oct 21, 2009
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Trucks done, runs and sounds good, but... at 1500 rpms in all tunes the turbo canes are shutting all the way and making way too much boost, if you hold it at 1500 rpms it comes and goes like its doing a vane sweep, I’m stumped.

put the stock tune in it and see if it still does it. if so, hard part issue. if not, tune issue. the unison ring may have rusted up some from sitting and is now sticking a bit
 

Chevy1925

don't know sh!t about IFS
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Oct 21, 2009
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probably an exhaust leak. that would not help the surging issue either. look for soot around all exhaust gaskets. pulling the up pipes and looking at the gasket for any soot coming out between where its suppose to seal will tell you right away too. most of the time the leak is at the up pipe gaskets somewhere.
 

JoshH

Daggum farm truck
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I have found a squeal under load is typically a driver pressure leak from an up-pipe gasket.
 

Bdsankey

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probably an exhaust leak. that would not help the surging issue either. look for soot around all exhaust gaskets. pulling the up pipes and looking at the gasket for any soot coming out between where its suppose to seal will tell you right away too. most of the time the leak is at the up pipe gaskets somewhere.

Problem with pulling the gaskets is 9/10 (in my area/experience) the bolts break off in the manifold.
 

Chevy1925

don't know sh!t about IFS
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Oct 21, 2009
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Problem with pulling the gaskets is 9/10 (in my area/experience) the bolts break off in the manifold.

hes already had the top end off. if they break off now, its cause they cross thread and never fully tighten so regardless, he will have a leak. hot engine, soak of penetrating oil and a wrench get them out every time for me but i dont deal with the back east rust bull shit.
 

Bdsankey

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hes already had the top end off. if they break off now, its cause they cross thread and never fully tighten so regardless, he will have a leak. hot engine, soak of penetrating oil and a wrench get them out every time for me but i dont deal with the back east rust bull shit.

Yeah, everything here is rusted to hell. Friends 2011 LML broke 5/6 lower up-pipe bolts @ 112k miles when we were trying to change gaskets.
 

WVRigrat05

Wound for sound
Jan 1, 2011
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French Creek, West Virginia
It’s definitely a boost leak close to the cab, I took it out and it got worse fast, those up pipes are an sob with the cab on, guess I’ll tear back apart. I used new gaskets and even torqued the bolts.
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
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Phoenix Az
It’s definitely a boost leak close to the cab, I took it out and it got worse fast, those up pipes are an sob with the cab on, guess I’ll tear back apart. I used new gaskets and even torqued the bolts.

its not uncommon that the "new gaskets" didnt seal... i actually reuse the factory up-pipe gaskets if they are in good shape still
 

WVRigrat05

Wound for sound
Jan 1, 2011
3,081
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French Creek, West Virginia
Passenger side up pipe and manifold was loose, I’ll not torque used rusty bolts again, good to go now. No soot anywhere until I pulled it apart and looked at the gaskets like you said James.