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Think I've got a bad vane pos sensor

Made an appointment Friday morning, thanks for the info Joe.

I don't think the VNT is jammed because it was cycling open and closed like mad at idle (the exhaust kept changing from rumble to hissssss) before I replaced the vane pos sensor and I generally don't drive miss daisy.
 
saratoga said:
Made an appointment Friday morning, thanks for the info Joe.

I don't think the VNT is jammed because it was cycling open and closed like mad at idle (the exhaust kept changing from rumble to hissssss) before I replaced the vane pos sensor and I generally don't drive miss daisy.
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Okay, then thats a good sign. Your also probably right about the code, the egr is calc based on maf flow, with the resonator off it will get most of its air through it and not the maf, so the maf reading reduces so much it thinks the egr is overly efficient.

On a side note, when was the last time you changed your fuel filter?
 
stacks04 said:
Okay, then thats a good sign. Your also probably right about the code, the egr is calc based on maf flow, with the resonator off it will get most of its air through it and not the maf, so the maf reading reduces so much it thinks the egr is overly efficient.

On a side note, when was the last time you changed your fuel filter?[/QUOTE]

Oh man...That would really suck if all it needed was a filter.:eek:

Actually, I can see this happening to me with my filter experiences and all.:D
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One bad batch of fuel can ruin a brand new filter. Good luck Friday Grady, wonder they'll charge you..
 
The control valve could also be bad. What happens is the valve operates and it gets bound up or goes to far, the sensor then commands a small change and it gets a big one. So its constantly going to run the test trying to find its limits and or the desired position. I wish i caught this before you ordered the sensor. They are very easy to test.
 
*Supposedly* it's all set.

The tech took about 20 minutes to talk with me on the phone about my concerns this afternoon which meant a lot. He asked me about the PCV re-route and I'm thinking "Oh boy, here we go..." Actually he wanted to know where I got the fittings to do it because he wants to do it to his own truck without the jerry-rigged plumbing parts that he had seen online. He told me that blocking the EGR and getting the crankcase vapors out of the intake is the best thing you can do to keep from having EGR problems.

He did a re-learn on the vane position, said that they command open and closed completely with the Tech II, re-flashed updates to the ECM because it was 2 or 3 updates behind, checked the balance rates (all good), rail pressure is good, vacuum is showing less than 3" after the fuel filter and test drove it. Told me it runs like a scalded pig.
 
I am concerned why it did not feel right after you did the sensor. Have you driven it and noticed a difference since the dealer had it?
 
It's back to normal after they reflashed it and did a relearn on the vane position. Plenty of power again, but it smokes a little at WOT now.

The way the tech explained it to me is that the relearn procedure needed to be done after the sensor was replaced because what the sensor tells the ECM is 0 or 100% may not acutally be so until you use the tech ii to command the vanes to both extremes to set what the min and max actually are.

He said that's why the boost was low and it kept throwing the P0402 because the turbo vanes were closed too far at idle causing too much backpressure.
 
saratoga said:
It's back to normal after they reflashed it and did a relearn on the vane position. Plenty of power again, but it smokes a little at WOT now.

The way the tech explained it to me is that the relearn procedure needed to be done after the sensor was replaced because what the sensor tells the ECM is 0 or 100% may not acutally be so until you use the tech ii to command the vanes to both extremes to set what the min and max actually are.

He said that's why the boost was low and it kept throwing the P0402 because the turbo vanes were closed too far at idle causing too much backpressure.
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Make sense then.
 
Hmmmm, ok. as long as its running better then i am happy for you. Thats all i care about. The lbz/lly ecm must be more sensitive to having it replaced because i did my sensor twice, once because i had a new turbo installed, and then because a dam squirell ate the dam harness, and never had the issues like you described. I am yet to do just the sensor on an lbz, turbos, yes.
 
My uncle has an LBZ and has had 2 turbos installed!!! and he still gets black smoke at about 3/4 throttle, wide open it smokes worse than my chipped cummins!! Dealer says its perfectly fine!!! so you might watch out!! NOT saying that your dealer is wrong!!
 
searstractorfan said:
My uncle has an LBZ and has had 2 turbos installed!!! and he still gets black smoke at about 3/4 throttle, wide open it smokes worse than my chipped cummins!! Dealer says its perfectly fine!!! so you might watch out!! NOT saying that your dealer is wrong!!
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It seems to be okay, boost goes up to 21-22 psi no problem.

Kind of leads me to believe that the reflashes are the reason for the black smoke.

God I wish I had EFI to see more of what was going on!!!
 
I have the code for the position sensor along with a maf code, Is it true that if I replace the sensor I have to have it recalibrated by the dealer?
 
It's best to have it calibrated, but the ECM is supposed to do a relearn every so often. Several have replaced them without a relearn without any issues. Just drive it easy for awhile until it relearns on its own.
 
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