VGT Duty Cycle

[Agjake11]

What does the range from normally?

had my truck sound like a 7.3 for a while at the end of a trip. then when i started it back up after about 20 minutes it wasnt as bad and after driving some it was back to normal. when it was not having the whistle it took a while to build boost and the vgt cycle was around 17-20% vs the next trip was 85% at idle and then down to around 40-60 when driving around and highway. thinking the vanes were stuck open?? truck now has powermax also.

videos.

Saturday

7.3 sound at end of trip

not as bad after started back up

 

[Super08Duty]

Wouldnt be a bad idea to pull it and check the vanes, as well as the actuator. Any turbo codes?

 

[Agjake11]

didnt check for any codes but ill see in the morning if it has any. it was running normal again after a few minutes of driving.

gonna see how it does tomorrow but if it happens again ill have to pull it and possibly pick up my 03 that i left at PSE.

 

[kingranchstroker]

How long ago did you swap turbos?

 

[Agjake11]

they were swapped technically about 3 weeks ago but truck wasnt running until friday. before that the powermax was off for a lil while but i think dorian went through it before it went on.

 

[Dieselcraft]

Sounds like a sticky unison ring or worn unison ring

 

[chappy]

My pmax is doing that crap when I go to accelerate hard and downshift. For instance passing someone. Only does it on a couple of the bigger tunes. I tore mine out and no sticking vains but a pretty worn unison ring. The turbo probably has 15k at the most on it and it was worn baddly where the actuator rides in it. Almost looked like it wasnt set in correctly from the factory and worn just one side really bad. I can say though that you need to check the wiring for chaffed spots. I found a chaffed wire where it had melted on the turbo oil supply tube and it was a map sensor wire. Was sending wrong signals I assume and don't know but ended up having my accelerator pedal fail shortly after. It still likes to stick on the hot tune but way better now that the other stuff is fixed. I assume mine is sticking due to the unison ring wearing funny on mine but yours could be a wire issue somewhere. I spent weeks trying to research and come up with what it could be.

 

[java]

How did the turbo sound driving around at higher rpm when it sounded like a 7.3?

 

[Pizza pig]

this truck was just apart yeah? My vgt duty cycle has always been odd after having all the keep alive memory cleared from having the batteries disconnected. Its always had to learn again, food for thought.

 

[Super08Duty]

sounds to me like the vgt is sticking or what weston said, sticking unison ring.

 

[chappy]

Just fyi the duty cycle is whats being commanded and not necissarilly what the turbo is doing. The computer could ask for 85% and only get 50% for instance if the vains are sticking. Also the duty cycle at wot is 35% I believe. The lower the number the vains are open and the higher the number the vains are closed to act as a smaller turbo which makes the hair dryer sound or whistle on the pmax. I believe the highest it will ever go is 85% and the lowest 35% but not sure on the lowest. I know it cant open all the way(lower number) or you would have vain and turbine blade contact as they would open into each other. As I said not sure on the lower number being 35% as the lowest.

 

[Agjake11]

My pmax is doing that crap when I go to accelerate hard and downshift. For instance passing someone. Only does it on a couple of the bigger tunes. I tore mine out and no sticking vains but a pretty worn unison ring. The turbo probably has 15k at the most on it and it was worn baddly where the actuator rides in it. Almost looked like it wasnt set in correctly from the factory and worn just one side really bad. I can say though that you need to check the wiring for chaffed spots. I found a chaffed wire where it had melted on the turbo oil supply tube and it was a map sensor wire. Was sending wrong signals I assume and don't know but ended up having my accelerator pedal fail shortly after. It still likes to stick on the hot tune but way better now that the other stuff is fixed. I assume mine is sticking due to the unison ring wearing funny on mine but yours could be a wire issue somewhere. I spent weeks trying to research and come up with what it could be.

I'll have to check out the wiring on it and see. Also when accelerating when it shifts from 4-5(from cts reading) the turbo will let off without me letting off the pedal. Im thinking this is just a tuning issue though

How did the turbo sound driving around at higher rpm when it sounded like a 7.3?

It started doin it after I got off the freeway after cruising for about 30-40 minutes. It would not have whistle and take awhile to build boost and then the whistle would come back at higher Rpms. It did that for the 4 miles from the hwy to my folks house. Then maybe another mile after we left there but the whistle came back a lot sooner.

this truck was just apart yeah? My vgt duty cycle has always been odd after having all the keep alive memory cleared from having the batteries disconnected. Its always had to learn again, food for thought.

Maybe this as well. Truck wasn't really running until Friday night and I drove it home quite a ways on the hwy the. Sat around town some but mostly traffic and the. Today this was the longest it's run about 45 minutes to the airport then some idle/traffic inside the. 30-40 home before it started the issue

 

[Agjake11]

Just fyi the duty cycle is whats being commanded and not necissarilly what the turbo is doing. The computer could ask for 85% and only get 50% for instance if the vains are sticking. Also the duty cycle at wot is 35% I believe. The lower the number the vains are open and the higher the number the vains are closed to act as a smaller turbo which makes the hair dryer sound or whistle on the pmax. I believe the highest it will ever go is 85% and the lowest 35% but not sure on the lowest. I know it cant open all the way(lower number) or you would have vain and turbine blade contact as they would open into each other. As I said not sure on the lower number being 35% as the lowest.

That makes sense. According to my cts though I was getting some 17-20% readings at idle and low rpm when starting to accelerate which sounds like that would be stuck open. And make sense why it took a while to build boost

 

[PowerStrokeEnginuities]

we reconditioned the turbo, im thinking that vgt is sticking from the turbo sitting so long.

 

[Agjake11]

no turbo codes. had EBP malfunction code. cleared them all and ill see what comes back tonight when i get home

 

[kingranchstroker]

Could be a bad ebp sensor causing the computer to keep vains open and act funny when driving.

 

[LiftedBlackHD]

Were you at a higher elevation when the issue occured?

 

[Agjake11]

Could be a bad ebp sensor causing the computer to keep vains open and act funny when driving.

Think they just got stuck from the turbo sitting for as long as it did. Haven't had any issues since in the last 100 miles with it. Cleared the codes Monday and all I have now are my egr code and my software incompatible with ficm code

 

[Agjake11]

Were you at a higher elevation when the issue occured?

If going on a freeway exit ramp over a freeway interchange counts then yes haha. Houston is flat for the most part so don't think elevation was an issue

 

[U235a4]

since you had a EBP code have you checked the difference between BARO, MAP and EBP during KOEO to see if they are within .5lbs of each other. That is if you have access to something that will show all three.