Engine/Transmission (1998.5 - 2002) Where's the boost?

[easleyj1]

I have noticed lately that when my truck is under load WOT that I am only showing about 14 psi of boost, was showing 20 under the same conditions. It seems to be as powerful as ever and is making no black smoke. I have checked the boots on all the turbo plumbing, cleaned the MAP and IAT, checked the turbo for wear, checked the gauge tubing and fittings and inspected the air filter for restrictions. So far have found no reason for this condition. I am trying to find another pressure gauge to double check my gauge reading. What other steps should I take before I get to the serious work of pulling turbos to check the waste gate and trying to pressurize the induction side to look for leaks. Thanks



Jonny

 

[Cummins724]

I would do the leak test now..... it will tell you if the wastegate is sticking or if a boost leak is detected.

 

[easleyj1]

Is there a simple way to do the leak down test. I have thought on it and can't come up with one.



Jonny

 

[Cummins724]

Is there a simple way to do the leak down test. I have thought on it and can't come up with one.



Jonny

I came up with a real HillBilly contraption for leak testing. I got a 4" rubber fernco & 4" threaded style cleanout cap [schedule 40 PVC] from my local Hardware store plumbing section. I drilled a hole in the end of the cap & screwed in a air chuck to fit my air hose..... then tightened down the cap into the fernco & the other end of the fernco tight on the turbo inlet. Set my air compressor regulator to 7psi & found leaks easily. It is a little Redneck, but works well for finding leaks.

 

[easleyj1]

Not so redneck, I was thinking about the black rubber air bladders that plumbers use to leak test their pipes.



Jonny

 

[Cummins724]

Not so redneck, I was thinking about the black rubber air bladders that plumbers use to leak test their pipes.



Jonny

Good One!..... you sure you ain't a little Redneck? :-laf