Ongoing problem that has been happening for a month or so now. Our pulling truck had a Danville performance stage 1 turbo on it, and suddenly one day I was driving it on the road and the vanes went completely open thus, no boost and lots of smoke. It was still driveable, just acted like a truck that didn't have a turbo. EVERY morning when the engine was cold, the turbo vanes DID actuate correctly, but after maybe a mile of driving it was back to the same thing. We swapped the vane actuator and did voltage tests on the actuator controls and still the same things happened. Changed the boost pressure sensor, same thing happens.

Took the turbo off and sent it to Danville to have it upgraded to a stage 2 2.6, get it back and everything had been hooked up it seemed to work fine, keep in mind the truck had been not started for a couple of weeks. The next day we finished putting the wheels and tires on and pulled it out of the shop, less than a minute later it was back the wide open vanes and no boost, no spool

The only parts of the new turbo that are the same as the last is the center chunk. And the only part that hasn't been changed is the vane position sensor

possibilties as to what could be wrong, vane position sensor? Programming (very doubtful, truck has EFI and DSP5)? Bearing in the oil feed line could have rotated to block oil flow to the turbo?

Please help!!! Thanks

any thoughts?

Mine does that once in a great while.

I've found two reasons:

The unison rings can get a crack on the inner diameter at the end of the vane slot. When this happens, the ring catches and will not release. Tap the turbo with a hammer, and she will free up. Common if you get your turbo real hot then cool it fast. Fixed that a while ago.

The other reason I have had recently it the new oil pump makes way high pressures when the truck is cold and jams the vane mechanism when the engine does it's system check. Hammer time again..

My charger seems to do the opposite. Seems like the vanes are fully open on cold start up, no boost. Once I get to the top of my driveway, about 100 yds, it seems fine. Has gotten worse with the cooler weather.

A new ecm fixed mine

That sucks... guess I'm glad I don't have to worry about that pesky little issue on mine :)

Mine does that once in a great while.

I've found two reasons:

The unison rings can get a crack on the inner diameter at the end of the vane slot. When this happens, the ring catches and will not release. Tap the turbo with a hammer, and she will free up. Common if you get your turbo real hot then cool it fast. Fixed that a while ago.
Did it with old charger and new charger so I know that isn't it. Happens almost exactly 2 minutes after cold start up. Nothing has changed setup wise and has been running the same tuning all year and this just started in the last month or so. I haven't seen the truck in person to see it with the Tech2 to see what the sensor readings are doing.
The other reason I have had recently it the new oil pump makes way high pressures when the truck is cold and jams the vane mechanism when the engine does it's system check. Hammer time again..
He has high oil pressure but nothing like yours I am sure but it is the same as it used to be so that isn't it either.

Larry,
What was wrong with yours that a new ecm fixed it? This might be something to look into.

my vanes were froze at 99% closed, swapped an ecm from a used truck on the lot and all was well and working properly again, put the old ecm back in and vanes froze up again.

We got the truck fixed today.Tried a used ecm and had it reflashed at the dealer to gm stock specs. Truck started right up and the charger sounds sounds great. On the stock tune it boosts up to 40 psi. Be glad to get Mark at DP to get it properly tuned.Thanks to Mark and Larry at Danville Performance for thier help.

You say stage 2 is a 2.6 charger. Mark do ya'll offer a 2.8 charger yet or is that in the works or am I just that far behind the times??? lol.

Good to hear that fixed it David! When you get a chance to drag that beast up here I will get it dialed in for that new charger! It should run really good...

You say stage 2 is a 2.6 charger. Mark do ya'll offer a 2.8 charger yet or is that in the works or am I just that far behind the times??? lol.

I actually have three different versions of the stg2 chargers, 2.5, 2.6, 68mm. I do not have a 2.8 version yet but you never know what the future will bring!

We got the truck fixed today.Tried a used ecm and had it reflashed at the dealer to gm stock specs. Truck started right up and the charger sounds sounds great. On the stock tune it boosts up to 40 psi. Be glad to get Mark at DP to get it properly tuned.Thanks to Mark and Larry at Danville Performance for thier help.

Maybe this is a dumb question but, I thought on the VGT trucks the boost is entirely controlled by the ecm? Meaning no matter what mods are done to the turbo, only an altered tune can create higher boost levels.
Doesn't a stock LLY or LBZ only make something like 22psi?

Maybe this is a dumb question but, I thought on the VGT trucks the boost is entirely controlled by the ecm? Meaning no matter what mods are done to the turbo, only an altered tune can create higher boost levels.
Doesn't a stock LLY or LBZ only make something like 22psi?

Hehe, good point buddy but when you have the parts that he has it will make 40psi even with the stock tune file no matter how hard the computer tries to only produce the 22psi. VGT's are great!:D

Hehe, good point buddy but when you have the parts that he has it will make 40psi even with the stock tune file no matter how hard the computer tries to only produce the 22psi. VGT's are great!:D

10-4:thumb:

I actually have three different versions of the stg2 chargers, 2.5, 2.6, 68mm. I do not have a 2.8 version yet but you never know what the future will bring!



Mark, When you come out with the 2.8 charger later what is it going to be 71.what? thanks

We got another problem ,we loaded a ppe hot plus 2 program to try out the new charger.The truck had a lot of smoke,I think the 60% injectors are wrong for the tuner.So we took the tune out and returned to the stock file.Now the truck will not start.If we take the ppe and load a stock tune the truck starts right up.I think we will have to have it reflashed and take it to Mark to dyno tune.Any one seen this before.The tuner has current upgrades and works fine on my son's lmm.

The same problem is back! Drove the truck a couple times and the charger seemed normal.Then after driving about 1 mile the charger went away.Whistle and driving boost is gone.WOT will boost up to about 30psi .What could be doing this?Had already changed the boost sensor,maf sensor and put another ecm with stock gm settings:thought that was it.Now back where we started.Any ideas where to start? Please Help.

did you use that ppe 2(same unit) on it before, and then started acting up. wonder if any pins going to ecm might be loose and moving around or bent over. just some thoughts.

check for boost leaks