04 CUMMINS when its under a load like pulling my fifth wheel it starts Turbo surge so bad I have to downshift into tow haul or just pull over!!!! The truck is totally stock exert for Smarty ssr 5inch ex and cold air. No codes and still does it with programer off.

 

Is it like someone is pressing on the pedal even though you aren't?

I get that sometimes with my '03, as soon as I let of the pedal it goes away. Been fighting with it for 3 years now.

 

No its the Turbo surging like when under a load and letting off the pedal too fast. Alot of people complain about it in that way but mine is
Doing it under heavy load with the pedal mashed!

 

Do you have boost, low side & high side fuel pressure gauges?

These would help to determine what is exactly surging.

For example, my truck surges a bit when empty on the highway on cruise control.
I can see the rail pressure going up & down a bit on the gauge which of course causes the boost to vary slightly.
It turns out this is completely normal with a modified FCA in the CP3.
I have the Arson kit in my CP3.


Have you checked out your turbo? Shaft spins easy, end play?
How about the basic stuff too? Air filter clean? Recent fuel filters?

 

Yes its the turbo . The boost guagestarts bouncing like crazy! As for air and fuel filters they are new. There is a lil play in the Turbo both directions.

 

Is yours and 04' truck or 04.5'? First thing to do is check for a boost leak. Is the compressor wheel rubbing the housing?

 

Another thing to do is clean the MAP sensor in the intake. See if it has trash all over it.

 

Its an o4 n the wheel isn't rubbing the housing. I will check the map sensor.