I have mentioned before that I can see ~35 psi of boost while towing a hill when the truck downshifts. On the flip side, many times while cruising at hwy speeds ~65 while towing, my boost level will drop well below normal and I get a dead pedal unless I punch it to force the truck to downshift. This is all while towing ~11k fifth wheel. Not towing, the truck runs perfect with max 26 psi of boost. Not sure if posting the youtube link will work but lets see....maybe admin can help me here.
Mods: EGR cooler delete, I removed and cleaned turbo last year due to sticking. Any suggestions from the experts?? Thank You!!!

The first video is all gauges towing 11K at ~65 mph, had dead pedal feel upon trying to accel. Also, as boost drops, EGT seems to rise.

YouTube - Psd

The second video is about 5 minutes later still 11k ~65 mph...this seems more normal. Note the lower EGT despite same speed and terrain.

YouTube - Psd

 

Cheezit...... M-chan..... bismic..... I need the pros on this one

 

your turbo's unison ring is getting hung up for whatever reason (yes, it's sticking again) after 15-30 seconds you should find boost levels slowly rise and go back to normal, and yes, you are experiencing significant EGT's the longer you mash the go pedal in this condition.
Are you running a tune?

 

No tune. Could this also be the vgt solenoid? Is there a reason I only see this while towing? Boost is consistent while not towing during fwy speeds. How much material can you take off the housing while cleaning it up? If I remember, mine was pitted.

 

the solenoid might be working fine but you won't know unless diagnosed. You'll have to find out the reason the unison is having trouble turning.
By using 3M coarse pads you shouldn't have to worry about anything.
You can also check the Tech folder under Turbo Rebuilding for pictures and ideas if you're going into it again.

 

Any idea how to diag a vgt solenoid?

 

You can unplug it to see if it replicates your problem but chances are it may need to be cleaned.
The solenoid valve is very sensitive to contamination. Check for coked on oil which will make the valve sluggish to respond. If you find coked on oil you may need to replace the turbos' oil feed tube. (It's the flexible braided feed line) change it to the larger solid type.

To clean the VGT actuator; your work area must be clean before starting this procedure. Do not allow contamination to enter the valve ports, cam follower, or turbocharger housing. Handle the VGT actuator by the solenoid body only. Do not attempt to wipe oil off the valve. Do not let the valve come in contact with materials that could contaminate the valve mechanism.

Use only Carburetor Tune-Up Cleaner PM-2 to spray the actuator valve. Brake cleaner or other solvents may damage the actuator valve so be careful when you clean it.

 

Can anyone explain why the truck only does this while towing. You would think if the turbo is sticking, I would see it all the time.

 

a more heat
b more load.
c partly pluged exhaust maybe. I would have to play with the truck for a little bit to figure that out for sure.
I also wonder if the boost gauge is accurate.

 

Off topic, but what brake controller are you running there...it looks neat.


Also I'm with Cheez on this one, those turbos will do funny things while under load. I had almost the same thing going on after the dealer cleaned it. It would only happen while towing my GN. They had to replace the center section on the turbo cause the unison ring was siezed. They added some grease to the new one and I havent had a problem sice.

I dont drive the truck every day either so I would notice it/have problems sooner than most. It sometimes will sit for a month before it gets driven, but when it runs I drive it hard and for long periods of time.

Sarge

 

Any way I could check for plugged exhaust issue? I am thinking of taking the cat off, could that help?

 

If the cat was plugged I would think you have high EGT's all the time, also the truck would bog down and run poorly too. You can remove the cat f you want but if you live in an emissions state where they test you, visually of if they run a sniff test you will fail. MBRP sells a test pipe you can remove and install the cat fairly easily.

Do you have any exhaust leaks in the flex pipes?

Sarge

 

No leaks that I am aware of. No abnormal smells or signs of leaks under the hood. Although it may be hard to see the flex pipe without removing the inner fender.

 

Sometimes you can get a look at it from underneath with a flashlight. If its leaking bad enough you will see soot around the pipes.

Sarge

 

I will check. My brake controller is the prodigy p3 if I remember correctly.