While climbing a mountain pass or stepping on the accelerator I hear a strange "burping" sound coming from the passenger side of my Cummins 305/555...It seems exhaust related like around the turbo area...Is this normal or could a sleeve or part of the exhaust be loose?

If I step on the gas and let off it does it but more so when the truck is going up a steep hill and I let off...

 

Does this sound familiar to anyone? I'm just wondering if lots of people have this happen or I'm driving it wrong up the pass with my Auto. I have to slow down for the curves as the HO Cummins seems to charge up the hills. Would an Edge EZ or TST box lessen the effects. I guess if its not harmfull I won't worry about it.

http://dodgeram.org/tech/dsl/FAQ/turbo_faq.htm

When my throttle snaps closed, there is a brief whoosh or whistle sound from the air filter area. What is causing this?

When the engine is loaded, very high turbine speeds are required for the turbo charger to provide intake manifold boost. When the fuel is suddenly cut off, the exhaust volume collapses and the turbocharger rapidly spins down. As the turbine looses speed, it looses it's ability to sustain the manifold pressure and compressed air rushes backward from the manifold and through the turbocharger. The momentary airflow reversal is not harmful and produces the short pSSHTT sound.

 

From what I have heard, "turbo bark" can be quite harmfull to the turbo so try to avoid it!

It makes sense that it barks going up hills more often because there is more boost pressure when the engine is working harder (you can hear the turbo easier going up hill).

I don't know how to prevent this except trying to let off the throttle slower maybe? Good luck with your troubles. I know I've heard about others having this problem so you should get some good responces.

 

Every time the turbo surges, it unloads the compressor impeller blades. When the turbo starts compressing air again, the compressor impeller blades are loaded. On larger turbos, the cyclic fatigue resulting from surge is a major cause of impeller failures. The smaller turbos on our trucks are somewhat more forgiving, but only because the blade thickness is large relative to blade height as compared to the larger turbos. That notwithstanding, I would suggest avoiding surge as much as possible.

Rusty

 

The 600 engines seem to idle down slowly on their own to avoid this.

 

Correct, my 600 is almost impossible to "bark" while two friends of mine have 555 engines, and they do it constantly. One has 40k miles and the other has 60k. Neither has had any problems and neither one is stock by any means...

 

Is there a Service Bullitin on this for folks with the 305/555...seems like you could flash the engine control computer to behave more like the 600s do and idle down slowly. Maybe a setting that can be changed with the DRM tool.

Randy

 

My 600 does it and was getting ready to take it to the dealership. It started about 3K miles ago in 5th only now it does it in 4th and 5th. Not all the time, mainly under heavier acceleration I am now at 28K miles