Failed visual test

JAG91761

Member
Mar 12, 2018
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Ontario, California
Did smog check(CA), everything passed except pcv. I do not have the stock parts, but I re routed it back to the intake elbow and it’s smoking like crazy out of the tail pipe. Am I missing something?
 

2004LB7

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Dec 15, 2010
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Do you have the positive crank case release valve installed? If no it will draw in excessive vapors and increase smoking
 

Lennydmaxguy

Just another diesel tech
Nov 8, 2023
48
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Somewhere, USA :)
Actually, that is nothing but a tube with a Y connection. The "Positive" part of the system is a little diaphragm on each valve cover that has a small spring and rubber valve built in. I ripped out the rubber and the spring when I rerouted mine. If the same mod was done to yours, the vacuum from the intake will suck oil into the intake.
 

Lennydmaxguy

Just another diesel tech
Nov 8, 2023
48
27
18
Somewhere, USA :)
pcv-jpg.359841


This is the diaphragm I mentioned. Looks like you can get replacements. https://dansdieselperformance.com/i-30502205-pcv-valve-kit-lb7-lly-2001-2005-duramax.html
 

2004LB7

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Dec 15, 2010
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For some reason I was thinking they changed it on the LLY to that part. I have an LLY and didn't even look 😛
 

Lennydmaxguy

Just another diesel tech
Nov 8, 2023
48
27
18
Somewhere, USA :)
Thanks Lennydmaxguy do you know if I can remove the plate with out removing the valvecovers? I order the parts, do you know if goes gasket spring then cover?
Yes, the plate comes off with the 4 Phillips screws. The picture 2004LB7 attached above shows correct install order. The spring fits into an opening in the valve cover, and the rubber diaphragm goes on top.
 
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