Hey guys,
I've been searching and reading for 2 days with no luck, so I'll start a new thread:

I'm having issues with my EBP/ Vgt on my 2005 F-350 6.0, I'm using torque to monitor.
EBP reads same as Baro/Map at KOEO, (12.9 in my case, high altitude) about 18 psi at idle, but rises very quickly. (18 idle, 20-40 at low acceleration, sticks at 53.0 when cruising, moderate accel)
I've gone through 3 new EBP sensors, last 2 have had the same pattern(using motorcraft). New pigtail is installed, tube was cleaned thoroughly. Checked ohms/voltage at pigtail with my cheap multimeter, I believe it's fine (5V, 0.5V, 0.4V ground, 56k, 300, 300 ohms).

VGT at startup is 60%, then progresses (over maybe 10 sec) down to 15%, where is then stays UNLESS I get out on the highway then it will suddenly occasionally lurch up to 50% and back down to 15%. This seems important, like a loose connection somewhere? Any thoughts? The whole time it will run like crap and occasionally roll mass amounts of coal.
When I unplug EBP (it defaults to 6.3 psi) and drive around the VGT stays between 40-60% but still runs like garbage and blows smoke.

Turbo was rebuilt a couple months ago but has worked fine until now. I'm sure the unison ring must have been cleaned as the guy who did it is a 6.0 expert. Hasn't shown any signs of sticking that I've noticed.

It would seem my VGT is fine, my EBP sensor is new, the pigtail shows voltage and continuity fine, and I'm lost and angry because I want to go hunting this week.
Help?

 

codes ?

 

P0046
P0472
P0478

A couple for my kill switch and missing compass

And I tried unplugging VGT, that's probably the P0046.

 

Maybe someone can help me more with my pigtail testing? Starting to suspect I may have missed something there, followed the tests I found online.

 

Did you check the MAP sensor, hose and nipple for leaks/function? EGR valve and air filter clean? The VGT connector is prone to breaking one or both clips. Might be loose.

 

For now I will assume that P0046 was trying to start w/ the VGT unplugged.

P0478: Stuck Turbo, bad EBP sensor, slow responding (bad) VGT sensor, stuck VGT valve, bad PCM.
This code is set when EP_G is higher than EP_DES by 260 kPa or 37.7 psia for greater than 30 seconds.
A stuck turbo can give EGR codes, but a bad EGR can not cause turbo codes!

Maybe P0478 is also from the connector being unplugged, but am not 100% sure.

I believe that P0472 is your main issue.

P0472 is an electrical code ONLY. It could be the EBP sensor OR the wiring to/from the sensor. Also, it could be an issue with the "signal return" circuit (which is a sensor ground circuit to the PCM) that is shared with several circuits ...... or it could be the "signal" circuit itself. It could even be an issue with the v-reference circuit - which could be caused by issues at the EBP sensor or possibly another sensor on that circuit. The EBP sensor v-reference circuit also supplies the EGR valve and the ICP sensor (Brown wire with White stripe). The signal return circuit is a Gray wire with Red stripe and is common to the same three electronic components (EBP, ICP, EGR).

 

Problem appears to be solved.

Tested VGT solenoid with ohmmeter and it tested perfect (~4 cold, ~6 hot) so I had tentatively ruled that option out but after chasing many other options we swapped in a new solenoid and it appeared to fix the problem.

My codes were reading EBP high and EBP voltage low(maybe just from unplugging while truck was running), no turbo codes at all, but my VGT was just stuck in "tiny-turbo mode" so exhaust was over pressuring and then it couldn't deliver enough air at higher RPM. I never did see a P0299 though.

If you have this issue, don't be afraid to find another solenoid to try because even though mine tested fine it appears to be working with the new one.
Hopefully it stay that way.

Thanks for the help guys.

 

Woohoo, nothing like the feeling of a truck running again. I've not done this before; does swapping that solenoid require taking the turbo off the truck? Any other reason to give the rings and vanes a good cleaning as well? Is this the issue where the vanes can stick wide open as well, kinda one or the other randomly?

 

Yeah no kidding,
turbo stays on the truck.
This is one situation where the vanes can stick open but if its caused by the VGT solenoid, unplugging it should let them relax and close for an easy test (I think I got that the right way around)
Could also be stuck unison ring.