High EGT's, lack of power, black smoke, poor mpg

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domeniccurulla

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Jun 1, 2020
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I have a 2006 ext cab long box Duramax, tuned, deleted the egr smog stuff, 4" exhaust, upgrades the downpipe, no cat, tires are just 265's. Before I could hammer it & no smoke, took off hard & egt's would take a longer than I needed to pass (or race) anyone I tried. Now the more I push the accelerator the more smoke comes out to where if I gun it the thing looks like I have a dump switch just about. When I gun it the EGT's jump crazy fast sometimes in a second or 2. Climbing Snoqualmie Pass before I could do 80mph with my EGT's barely moving now I have to keep it at 65mph or less. It gave me a turbo vane positioning sensor code. I am pretty new to Duramax's & diesels in general. Has anyone had this issue or any ideas?

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Bdsankey

Bdsankey

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domeniccurulla said:
I have a 2006 ext cab long box Duramax, tuned, deleted the egr smog stuff, 4" exhaust, upgrades the downpipe, no cat, tires are just 265's. Before I could hammer it & no smoke, took off hard & egt's would take a longer than I needed to pass (or race) anyone I tried. Now the more I push the accelerator the more smoke comes out to where if I gun it the thing looks like I have a dump switch just about. When I gun it the EGT's jump crazy fast sometimes in a second or 2. Climbing Snoqualmie Pass before I could do 80mph with my EGT's barely moving now I have to keep it at 65mph or less. It gave me a turbo vane positioning sensor code. I am pretty new to Duramax's & diesels in general. Has anyone had this issue or any ideas?

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Click to expand...

How many miles are on the truck? If its throwing a vane position code (either bad sensor or vanes not at the desired position) then its possible that there may be an actuation or sensing issue causing the vanes not to properly function. If the vanes in the turbo don't function properly you can have the exact issue you're talking about.

How clean is the air filter and what type (OEM paper, oiled, dry etc)? Have you cleaned the MAF recently? Another good step would be to check for boost pressure leaks just to make sure none have cropped up.
 
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domeniccurulla

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Jun 1, 2020
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Bdsankey said:
How many miles are on the truck? If its throwing a vane position code (either bad sensor or vanes not at the desired position) then its possible that there may be an actuation or sensing issue causing the vanes not to properly function. If the vanes in the turbo don't function properly you can have the exact issue you're talking about.

How clean is the air filter and what type (OEM paper, oiled, dry etc)? Have you cleaned the MAF recently? Another good step would be to check for boost pressure leaks just to make sure none have cropped up.
Click to expand...
Just over 300k miles she has a K&N air filter that I have cleaned 2 times since this issue started. I have not cleaned my MAF (not even sure what it is to be honest). I have a CTS2 controller but it stopped working. I am mailing it in today for repair. The CTS2 shows boost if I am not mistaken. What should my boost be?
 
Pure Diesel

Pure Diesel

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First off, dump that K&N filter and either put in a dry type air filter or the factory one. Clean the Mass air flow sensor(MAF). If you've oiled the K&N twice, you probably have over oiled it . Then it gets on the MAF and cannot read correctly.
 
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domeniccurulla

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Pure Diesel said:
First off, dump that K&N filter and either put in a dry type air filter or the factory one. Clean the Mass air flow sensor(MAF). If you've oiled the K&N twice, you probably have over oiled it . Then it gets on the MAF and cannot read correctly.
Click to expand...
When I say oiled the K&N twice I meant cleaned & then oiled it. What is the recommend way to clean the MAF?
 
Pure Diesel

Pure Diesel

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How much oil did you put on it? There is more air being pulled through because of the turbo and the oil can get on it. Go get some MAF cleaner and follow the directions. Only use MAF cleaner. The MAF is on the intake tube after the filter housing. Two T-? screws usually hold it in place.
 
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domeniccurulla

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Pure Diesel said:
How much oil did you put on it? There is more air being pulled through because of the turbo and the oil can get on it. Go get some MAF cleaner and follow the directions. Only use MAF cleaner. The MAF is on the intake tube after the filter housing. Two T-? screws usually hold it in place.
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Ok I will go grab some & try to get that done when I get home. Will I need to unplug my batteries to reset the CPU after?
 
Bdsankey

Bdsankey

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domeniccurulla said:
When I say oiled the K&N twice I meant cleaned & then oiled it. What is the recommend way to clean the MAF?
Click to expand...

I say to clean the MAF because over-oiling the filter will cause excess oil to be sucked through the filter media and onto the MAF (mass airflow sensor) and cause it to read incorrectly.

domeniccurulla said:
Ok I will go grab some & try to get that done when I get home. Will I need to unplug my batteries to reset the CPU after?
Click to expand...

No, just make sure the truck is off. Unplug the MAF, unscrew the MAF, clean it/dry it (follow directions on the can of MAF cleaner), reinstall the MAF.
 
JoshH

JoshH

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A dirty MAF sensor won't cause excessive smoke. I would be looking into the vane position code and looking at how much boost you are seeing.
 
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domeniccurulla

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I sent off my CTS2 yesterday & will be at the shop Saturday. The guy said it's a 5 minute job so I should have it back by next Thursday so I will have to wait until then for the codes since I don't think my scanner does diesels

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Dozerboy

Dozerboy

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JoshH said:
A dirty MAF sensor won't cause excessive smoke. I would be looking into the vane position code and looking at how much boost you are seeing.
Click to expand...
I agree. Stock the vane and boost is aggressive On the low end. If you increased it down low that might be your issue.
 
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domeniccurulla

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It is not giving me any codes right now because somehow my truck lost juice (stereo was wiped too). I remember the code said vane positioning sensor. If we need the actual code I will have to drive it for a while which is ok cuz my metro is down for a couple days
 
LBZ

LBZ

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Nothing wrong with the k&n. I ran one in my lbz for 10 years. Just don’t over oil it.
I’m guessing you’re about due for a turbo @ 300 000 miles and smoke, codes, etc.
 
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