Please help Paccar

Do you have a Exhaust temp gauge?

 

Cac leak, boot leak id look there first.

 

Itll increase, just it isnt going into the engine. Expanding psi can stretch open a small crack/leak into a big one. a pyro gauge will tell you if its getting suddenly hotter, which would tend to indicate lack of cooling air into the engine.

its cheap to check boots and cac before you dig deeper.

Also, if you have it tuned, but are using a stock turbocharger, you may be making more boost at an ineffective range/ higher psi but with not enough volume. Idk what turbo paccars use, or what the effective boost range is. A baby could breathe thru a straw, a grown man would slowly run low on o2 saturation of the blood breathing thru a straw. But a grown man would be pushing n pulling a higher psi through a straw than a baby would.Bigger demand for air may require a (larger) different charger.

 

Get it on a laptop, it most likely has codes that wont show on the dash.
Replace the exhaust manifold pressure sensor and remove the tube and clean it. Leave the sensor out and run the motor to verify exhaust flow to the sensor.

Remove the linkage from the bpv and wire it open.

 

Intake manifold pressure reads at the head, if a charge air boot/cooler was leaking it will drop in pressure.