cat 3406e low boost??

i have a 99 kw with a cat 3406e, when loaded the turbo boost its around 18-22psi, at 1500 to 1700 rpm it will go to 25psi, on 10th spd no matter the rpm, it will not boost more than 22psi.... on any hill, even an easy hill, it will lose power, and as the rpm declined, so its the turbo boost... the turbo has no wastegate, and im thinking its a turbo problem... what do u guys think? had an overhead done last week, intercooler check for leaks today.

 

Have you checked for an exhaust leak at the manifold?any check engine lights come on?.how does the turbine look on the intake side of the turbo?

 

Yes I have,.. everything seems normal.... even if the truck its empty, that's all the boost I get, 22psi....what about the computer?... can it limit the boost?

 

Have you considered the boost sensor?

 

If the boost sensor is bad, woul the computer detect it??... where is the boost control located?

 

The boost sensor often slips through the cracks like cam position and engine speed sensors can do. They malfunction without setting a code or check lamp. The sensor is on the left front of the engine in the cylinder head above the air compressor.

 

Ill, take a look at it... so do I need to replace it?

 

It's a very common cause of your issue and since there's no practical way of testing it, yes, we replace them with a known good part, a new sensor.

 

do u know like how they cost?

 

Not off the top of my head, but I can check on it. Well, I can't get you a price. You can call a dealer with your eng ser # and AR # and they will give you a price.

If your boost is decreasing only in top gear you may have a fuel issue causing the problem.