LBZ: vane position all over

[dylon333]

I'm having some problems with my truck. At first I thought it was tuning related but have tried multiple different tunes but doesn't seem to make a difference.

The vane position is all over the place. During WOT run it jumps from 50-60% to 0 back up to 50%. But truck seems to keep pulling and building boost. But every time I let off the throttle it goes to 0% and soon as I touch throttle is comes right back up to wherever it is commanded.

One other issue ive noticed. When I shut the truck down I hear a buzzing sound from under the hood, I'm thinking from the turbo area.

I'm leaning towards the vane position sensor. But after some research it seems like I would have signs of that in the idle but this only seems to be an issues during normal driving.

 

[2004LB7]

In the scan tool, Can you Command the vanes to 100% and 0% and what do actual show?

 

[dylon333]

I will try that when I get to work tmr.

 

[Dozerboy]

Sound normal to me.

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[dylon333]

I'm new to the duramax but this doesn't seem normal. the vanes are bouncing all over which cant be good for them, not to mention, the buzzing sound. But I don't have anything to compare it to other then my logs from few weeks ago, before I started noticing this, and the vane position never hit zero like it does now

 

[dylon333]

oo one other thing I cant for the life of me get my tow tune to work anymore either. where I command 98 % it just does whatever the hell it wants, and it worked fine when I put the tune together few weeks ago

 

[IOWA LLY]

Vanes are stuck


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[dylon333]

That's my fear. guess ill find out tmr when I hook scant tool to it

 

[dylon333]

They don't use vane position for shift defuel do they?

Dozer boy hit me thinking. maybe it is my tuning. After watching the edge insight I'm thinking maybe it's hitting the desired boost and opening the vanes to bleed pressure. Correct me if I'm wrong on my understanding that the vanes act as a waste gate?

Of course I didn't bring my computer to work today so can't chant abutting till tonight

 

[jpowel29]

Under normal load (steady rpm) do the vanes still fluctuate? A faulty vane position sensor can cause problems similar to what you are describing. Do you have any drive pressure (exhaust leaks)?

 

[Dozerboy]

They don't use vane position for shift defuel do they?

Yes. Think about it vanes are based off of fuel and rpm. So when you have shift that defuels and drops rpm it’s going to to fallow. My vanes also go to 0 when I let off the throttle. Post a picture of your logs showing the change in your vanes and maybe we can Give you some insight if you have a problem.


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[dylon333]

They don't fluctuate under steady load that I have noticed. I'll pay closer attention.

I'll post pics tonight. Of the vane log.

 

[Chevy1925]

put the 100% stock tune back in and log it. if it still does it, its vanes sticking. if it dont, its tuning

 

[dylon333]

I think I found my issue. So some how in the learning curve here I deleted my egr, but managed to some how turn it back on, so it was using the egr on tables. At least I think.... Man I'm struggling learning this duramax tuning haha. I appreciate you guys being so understanding.

 

[dylon333]

Turning egr off.... Again. And playing with desired boost tables seems to have fixed the issue. Now it pulls really hard all the way through. Now just got to figure out the shift defuel. Some times it does it, some times it doesn't and feels like it slips. Usually under wot it shifts good but then just cruising it seems really soft and mushy

 

[Dozerboy]

I think I found my issue. So some how in the learning curve here I deleted my egr, but managed to some how turn it back on, so it was using the egr on tables. At least I think.... Man I'm struggling learning this duramax tuning haha. I appreciate you guys being so understanding.

That happened to me. Once we had a cold spell that turned on the EGR and I could only make 25psi of boost.


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