I was towing my 7000# travel trailer last week and I noticed that the engine seem to have and unusual amount of exhaust noise. I noticed that my boost was very low around 3 lbs. and the truck was shifting down on every small grade. The boost would come up only when the engine RPMs went up with the down shift. this lasted for about 10 miles, then the boost returned to what I think was normal for towing which is about 10lbs on a level, and the exhaust nose was gone. the condition didn't happen any more with about another 100 miles of towing. Any one have any thoughts as to what might have caused this situation. the truck has bout 97000 miles on it.

thanks

 

What year is your truck and do you have gauges that read live data like scan gauge II or one of the smartphone apps like dashboss for IOS devices or torque for Android?

 

Sounds like a small (for now) leak in one of your CAC tubings..... check 'em for pinholes..

 

It sounds more like your turbo vanes are sticking open. This would most likely be caused by soot or corrosion inside the turbo, a failing VGT solenoid, or a bad connection in the wiring.

 

I agree it sounds like sticking turbo vanes. You may be fine now that it's back to normal. I agree 10 lbs to 20 lbs is normal for towing, depending on if you are on a hill or not, but you should be able to downshift under a load (like on a hill and punch it) and you should see the boost pop up to 28 lbs.

Brian

 

X2 on the vanes mine is in the shop right now for the same issue and only would happen in od scan gauge would go to 85 for vgt powermax turbo is in route

 

Ran into that same thing right after I bought my 04. Cleaning the vanes fixed it. If I ran it harder than I guess the other guy did, it would stick. Hwy pulling a hill/towing. Almost no boost, lots of black smoke. After some driving it would free and boost came back. It also starting sticking close and run boost high just before I tore it down. I could hear it from the cab. Mileage should have also been pretty bad on that run.

 

You can verify the turbo vanes sticking by installing a scangauge II and monitoring VGT right?

 

No, it only shows the commanded position, not the actual. If you unplug the VGT actuator and it acts the same you can assume they are stuck open, VGT actuator has failed, or there is a harness issue.

 

Get a code reader and see if you have a P0299 code. I had that and it didn't throw a cel. You can get that code for under and or over boost

 

How you can monitor vgt with a scanguage is to watch the vgt and exhaust pressure. Kinda guess work but you can see the vgt change to maintain exhaust pressure. It is the unison of the two to watch for.

 

Thanks for all you input I guess I will see if it happens again, it has been working fine now.

 

Interesting that I came across this...I was towing my boat last weekend and power felt really low. I am now wondering if I am having this issue. I can hear my turbo spool and then it goes quiet and I can hear the engine roar over the whistle. I didn't know what boost pressures I should be running at the time. Now I know and will be towing this weekend and will pay attention to see if it runs from 10-20 psi. My last 6.0L was an 03 and it pulled like a damn tank. I pulled my boat and 20 ft trailer loaded and would never even know it was back there...this truck feels like a gasser towing unless I get somewhat deep in the throttle.

 

A ScanGauge ll is still a good ins. policy for the future health of ypur engine.

 

I had this same issue a few months ago pulling our TT. 7500lbs dry 9K total. truck was running awesome! all of the sudden power started dropping off. like there was another 9k added. smashed the go pedal more and nothing improved. actually got worse. Boost ran up to 20 or more then dropped down. wouldn't go over 5-6 lbs of boost. Check engine light came on. Pulled over. ran codes. PO229. erased code. downloaded new tune. same thing. I reloaded tow tune and nursed it about 20 miles and all of the suddened power came back. Ran like before. set my scan gauge to VRT and watch the operation. Turbo varied between 42 and 62. Everything points back to the turbo and or VRT solenoid. I was on a 2500 mile trip so I couldn't just turn around. decided to run the pants off it. after about 1k. I noticed truck got more responsive and in climbing hills better. VRT/Turbo started cycling down to low 30's and up to low 70's. Now, a month later I've watched the turbo now vary between 23 to 85. Haven't had the light back on since our return home. I'll be taking the turbo off and cleaning it. More than likely this needs to be done on yours also. Vains are sticking. Just my .02 cents.