I am trying to figure out if my turbo is operating as it should. This is my first diesel so I have nothing else to compare it to. I recently had to replace my oil cooler so while I was in there
I broke open the turbo for cleaning. Found the unison ring was seized to the body. Well after finding that I was expecting to see a big difference in performance but I see absolutely none.
I have Forscan and according to that it's making boost. The VGT% runs in the 40s - 50s while driving. Will drop into the 30s when I put foot in it. At idle its around 70. When hard accelerating (3233 rpm) I have recorded a 19.9psi difference in BARO,psi and MAP, psi. I have also previously used ODB fusion and that has a PID with an actual Boost gauge. That showed boost as well. This was before I even cleaned the turbo.
I am concerned because of couple reasons. I don't see how it could have been working properly prior to my cleaning and if it wasn't why don't I see and feel a notable difference in performance. Second is I can't hear it at all. Not under the hood. Not at the exhaust. Not in the cab with my foot on the floor. And lastly, I used it to pull my 28" camper a few weeks back. It was just a short trip but honestly I wasn't impressed with it. I didn't feel this 6.0 pulled any stronger than my F150 with 5.4. I thought that was odd from the get go but after I found the unison ring stuck I just figured I had found my issue. Maybe there isn't an issue and everything is fine but I'm just curious. Besides what parameters the gauges I listed show how would one go about verifying proper function of the turbo?

 

if you did not do a "re-learn" procedure after the work you did, doing that might help. Google "6.0 re-learn" it's been posted a lot. Also while doing the re-learn the turbo vanes will be commanded to various position through the full range of operation. During this you should hear the turbo make some noise, whistling and changing to deep exhaust note occasionally.Also the VGT numbers you have monitored sound like they are inline with what is expected, but these are commanded numbers, not actual VGT position. So, doing the re-learn you can at least verify that that vanes are moving and not somehow stuck,

 

Unplugged my VGT solenoid and tried to drive it. That was a no go. It didn't have enough power to pull over, which told me that obviously my turbo was working. Plugged the solenoid back in and after driving home did the re-learn process. Watching my VGT% I could hear a tone change with each % change as it was going through the sequence. So while I can't notice a huge "seat of the pants" difference I am now at least confident the VGT is working as it should.

 

What are you seeing for max boost numbers?
It's an 03, so if you still have the stock 10 vane turbo you should hear the whistle like a Lear jet doing a run up before take off.
Something is amiss if it's only as good as your 5,4. That 6.0 should run circles around any 5.4

 

now that you have at least verified that the vgt is working (that would have been too easy) you will have to dive in deeper. non turbo issues maybe the cause of lack of performance. first you could verify that the fuel side of engine mangement is within the expected range. With forscan get numbers for ICP mainly hard acceleration, the ICP should be about 3600 psi and the IPR around 70-80%. of course this is just to see that you have the control pressure available to inject the desired fuel and doesn't confirm that is taking place. but that is the usual starting point.
some of the finer tuning is done by temperaturee sensors, EOT, ECT ,IAT (1&2) so at cold soak temp al of these should be within a couple of degrees of each other and ambient. Pressure too, MAP and baro should be the same and about 14.7@ sea level. These are all KOEO. One common issue that shows up KOER and during acceleration is MAP issues caused by plugged nipple in intake or hose or cracked or broken hose. (passenger side of intake) take hose off and insert something or the other, to clear or verify nipple is clear. You could post all these numbers if out range. The more info you provide the more help you will get.
So if none of this finds any issues there could be an exhaust leak or boost leak, then pressure testing and more inspection, you can google that for "how too's". 19 psi boost is not what you should get, it seems that more like 26 is expected. however some say otherwise, saying that 20 is all it should be, but mine only get 20 and I know that it doestnt run as strong as it used to. Another thing, most people jump on EBP, particularly the sensor and connection tube. the 03's were re-flashed during an early recall to delete the EBP for the fuel/air management equation.
And one more thing, you truck should have had plenty of boost with vgt disconnected as it is supposed the default to open. It would struggle hard at first but if you are patient and coax the rpm up some the boost should have gone on up after the air catches uo to the fuel, so to speak.

 

Attached are two logs I recorded. These were done prior to the “relearn”. The first one is cruising about 60 and the 2nd is during a hard acceleration i need to set up an IPR.
As far as the comment about it eventually catching up without the VGT connected...I held it at about 3K rpm and it took it about a 1/4 mile to get to 55

 

only thing that jumps out is MAF, that should be a lot more, like, maybe 14-15lbs/min in the cruise shot and at least into the thirties or maybe 50 lbs per min? at hard accl 3200 rpm, since the pcm does't do numerical quantities and just voltages, and since this looks out of whack, look at MAFv. The voltage is 5v reference and the hard accleration v should be possibly as high as 4.2-4.4v (aprox), and as low as 1.5v at idle.

 

Can you go back to the beginning? did the truck run this way when you got it? how long have you had it? does it run any different than it did before the engine work? You can forget the EBP, since that is an inferred number, however, if that is what is inferred, 30 would be low. however any more than that I would be out of my depth and someone else can go there. Mine is also a low inferred number and I have wondered if EBP is ignored and the inferred number is low, would that have the same effect as low EBP on a non-inffered year model? Usually the EBP has a big part of the VGT calculation , or at least that is how I understand it to be.
About the turbo re-do, did you look at the u-tubes that explain the tooth engagement of the gear rack on the piston? a properly working vgt that is not engaged correctly could offset the real vgt. Your 31% WOT and 42 cruise look a little low. not sure if that means anything.

 

I juts got the truck in December. Truck was left to my wife by the passing of her father. I know nothing about the trucks history. The coolant/oil temp deltas were too high so I changed the oil cooler. While I was in there I cleaned the turbo. That brings us to today. I just set up a MAF % PID. Didn't drive it but while idling its 1.50.

 

I think you should use MAFv. That is the most meaningfull.

 

Check each and every exhaust joint between the manifolds and turbo.
One leaky joint alone can rob 2lbs of boost or more.
Knotreel gives good advice of other things to check in that earlier post.

Also, inspect closely the hot and cold side CAC boots for any tears, etc.