I've got pretty decent power in 1,2, and 3. (auto) I know I need to get a boost guage yet but I can tell you what its doing right now. I've got a nice whistle while accelerating up to about the point where the TC locks in 4th gear. Then I get a pshhhhh sound like the wastegate is open, then it goes back and forth between a nice whistle and that pshhhhh sound... like the wastegate can't make up its freakin mind. Any ideas guys?

 

Tell ya what I think Rex,

When your trans is in OD and the convertor locks, you are loading your engine for the first time since taking off. Because you load the engine, the turbo is making good boost and you simply hear the boost.

When I first starting making changes to my truck, I noticed the same thing. You could take off from a stop and not make a lot of boost until you locked the convertor in OD.

Because you are not making much boost in the lower gears, the wastgate is not opening. Only when you make enough boost (under load) will the wastegate operate.

I hope that helps.

Ronnie

 

This is my 3rd Cummins... and the other two don't do this... it really fluctuates ALOT! I can hear the wastegate dump on my other trucks but I think I just plain need to buy a boost guage and install it in this truck. I hate it when money is tight.