paccar px9 engine brake not working?

Any check engine lights? If so what are the codes?

The engine brake works by closing the vanes on the variable vane turbo.

No exhaust brake may be the 1st sign of the turbo or turbo actuator going bad.

 

Is it an exhaust brake? It might be working and you just can’t tell. If it is dragging your feet might be more effective. They used to put those Blue Ox brakes on 3406’s to help out the lazy Jake’s on those engines. They made it sound like a tree branch smashed a stack closed on you but that’s about all they did.

 

Pretty normal for exhaust brakes. Even with a Jake, we used to turn the fan on manually at times.14 or 15L engine you get 30-40hp worth of braking effort out of the fan. Exhaust brakes trap heat in the engine when they,re on so they trip the fan. They can use the extra brake effort from the fan too as they’re pretty weak to start with.

 

Yes it's normal for the engine fan to kick on with the exhaust brake, this is the main reason I really don't use the exhaust brake in our box trucks with PX-7 and PX-9 engines. It takes a couple of seconds for the engine fan to kick back off after you get back on the fuel, which I find highly annoying. And with the automatic transmission it's really difficult to control how much you slow down.

There are a couple steep hills with stop signs at the bottom that I use it for but that's about it.

Is this a manual or automatic transmission truck?