Update.....I pulled my camper 80 miles or so this weekend, rolling terrain some moderate pulls temps where good ( both ambient and deltas) truck ran great with the exception of an alternator problem (on another thread) hooked up and headed back home over the same trail and 30 miles or so into the return and the CEL comes on, checked codes and it's the dreaded PO299 again, soon after that I stopped, cleared it and continued on the rest of the way back home and it never did it again.....I had cleaned the MAP hose and nipple and the EBP tube and sensor prior to this trip because of the same reason and it had not bothered until now.......I do have the faint smell of exhaust from time to time in the cab but I have yet to find out why other than that IDK where to look from here....any suggestions?

The turbo seems to be sweeping like it should and I never see the boost above 27 or 28 so I don't believe an over boost is doing it......but IDK

The total trip was 160 miles or so and the terrain is equally hilly both up and down in both directions so the engine gets the same workout going either way.

 

When I pulled that same code a couple of years back, only while towing, it'd also get up to 27-28 psi.
After checking the turbo, the unison was completely stuck.
After the repair, I could only get up to 26 psi max. I also saw a reduction in acceleration power, as the turbo vanes worked properly and didn't allow for overboost, even though it originally pulled an underboost condition.
Good luck.

 

I thought p0299 is under boost.

I'd pull the turbo and clean it since everything else is cleaned.

The VGT is desired, not actual.... and since it's under boosting, means it's not working like it thinks it should be or what your seeing on the gauge.

 

I'm confused....so the dash gauge and scangauge aren't really telling me what the actual boost is? only what the engine/PCM wants it to be?

 

VGT desired is what the VGT solenoid is being commanded to do, not necessarily what it's actually doing. The VGT solenoid moves the vanes of the turbo.

The MAP sensor reads how much boost is being produced by the turbo in the intake manifold and reports it to the PCM. The dash gauge and SGII just read what is being reported to the PCM and convert it into real world numbers that are easy for us as users to read.

The PCM looks at MAP and EBP (with Baro as a baseline) and commands the VGT solenoid to open or close the turbo vanes according to the demand of the engine. The PCM also compares these values to the parameters programed and produce DTC's if parameters aren't what the computer wants after a certain period of time.

 

For a simple answer, yes they do.

 

Thank you for the explanation.....if I understand you correctly you said that the gauges are telling me what the turbo is actually doing, which is sweeping from nothing to approximately 26 to 28 psi. If that is the case what else could throw the PO299? or do I just have to bite the bullet and remove the turbo and clean it just the same? sorry if I appear to be somewhat thick headed but it's more than just an appearance I get no turbo fart or anything else that would lead me to do that other than the code it just seems strange that in 160 miles of towing up hill and down that it would only set one time and when cleared it didn't come back. Thanks again for the help.
for
....or does the turbo still do what my gauges say it's doing even when it's sticking? if that is the case it will clear up a lot of confusion for me.

 

Hope this isn't a stupid question. But what exactly is a turbo fart. And what causes it. And how does one fix it.

 

This is borrowed from Dieselmac in another post over on the DieselStop Maybe he'll see it and chime in with more info..Quote:
In a properly functioning turbo, excess pressure is relieved to the intake. When you let off the pedal you should here one whoosh of pressure relieving. Kinda sounds like a regulator dumping pressure.

What you don't want to here is multiple whooshes. Kind of sounds like thwat, thwat, thwat, etc.... This is usually a pretty good indicator that the turbo is sticking. What happens is the vanes on the turbo don't open up when you let off and it briefly keeps making boost. Thus the multiple "dumps". end quote.

Cleaning the turbo is how you correct it...or so I'm told

 

That's what I was afraid of. I've noticed mine makes that noise. But it only does it with in the first few mins of operation. Once the truck has been running for a few mins it clears up.
Sorry. Not trying to Hijack the thread.

 

P0299 is under boost and sets a DTC if pressure is 4psi or more less than desired and for more than 5 seconds.
Why your seeing it only under load and only towing, because the long hill. Most guys mash the pedal and then let off pretty quick because the tires are screaming, but not towing... you hold the throttle and get the under boost for more than 5 seconds of under boost condition because it's waiting for it to happen and it never does.

VGT is like they explained above. MAP reads the pressure, PCM commands the VGT to a certain setting and when it's reached.... based on feedback from MAP, VGT is relaxed. If pressure never gets high enough, MAP is still asking for more and turbo can't get there.... code set.

Turbo farts, I want farts when I let off fast from a quick throttle stab, it's the relief of pressure. You say yours doesn't? If the vanes are moving freely, the commanded VGT and solinoid movement should respond accordingly and pretty fast. Just the fact yours never farts says to me, it's not relieving pressure as fast as it should.... it should fart to get rid of the pressure, where else will it go... into the motor, out the intake or blow a boot off. Motors already said it wants no more because you let off, more air without the correct fuel is a lean condition and bad. It needs to dump it to the intake quick, Ford uses the VGT valve, Dodge uses a blow off valve..... you should be able to make it fart and if it doesn't, somethings not working correctly.... sticking vanes.

 

That I can understand, thank you and it looks like a turbo cleaning is in my near future. If I don't need any internal parts what do I need on hand when I do this? I have an 07 so I believe the oil lines are good to go but probably gaskets and anything else? and Thanks again for the help.

 

Same exact symptoms for me, after troubleshooting and rebuilding the only thing that solved the issue was a new turbo. No problem since.
By the time you buy an install kit, rebuild kit, VGT solenoid, unison ring, etc, you aren't very far from a new OE turbo.

 

OK, So I towed my T/T fifty five miles today in the
heat, up hill and down.......no codes and no issues. However I did watch the VGT numbers and when pulling hard they dropped to 14 and the highest I see was 84 anyone tell me what this means? I cleaned my EBP tube a while back when I started this thread and it was totally plugged, the weed wacker line I used was not as large as the inside of the tube so it obviously didn't clean it completely out, could this cause this and my issue mentioned in some of the past posts? I ask all this because I haven't pulled the turbo to clean it yet and I'm hearing now that it may be just as economical to swap it for a new OEM turbo.....I'm not looking forward to that if it could be something much simpler to correct.

 

The higher the VGT desired number the less boost the PCM is asking for. The lower the number the more boost the PCM is asking for. Remember that's a DESIRED number and not the actual position of the VGT/unison ring since there's no position sensor on the VGT.

AFA cleaning the turbo, you're looking at about $10 for a gasket kit. There's nothing that indicates a bad VGT solenoid or anything else at this point. I'd pull the turbo to clean it and go from there.