Ok, here's my story, I bought the truck for 1800 with a bad trans, so was unable to test drive before I bought recently found trans and installed, took it to get emissions done so i can get plates... Failed and not by a little bit, opacity limit ( whatever that means ) is 20 and at wot it blew 50.3, i'be seen your posts on what causes black smoke, praying its not pump, talked local shop into letting me use their scanner and found my timing at .60 where you guys say -1.94 is ideal, would that much off cause it to blow that dirty?
Turbo spins freely, waste gate wired open, new air filter
Truck feels sluggish too, I'd bet my s10 would out run it
Any help appreciated

 

does the black smoke ever clear up? when you say timing what timing setting are you talking about? -1.94 is the ideal tdco offset number

 

Yes i was talking about tdco, i read it with a snap on solus, it has light smoke under maybe half throttle, nothing i'd consider bad, but under wot it smokes pretty good through rpm range

 

i wouldnt really trust the snapon scanners for these trucks. the one at school says i have a -2.20 tdco offset. well according to the gm manuals that is very out of spec and it would have thrown a code. well my ip was recently done by the gm dealer so i doubt its that far out of spec and i have no codes. this also happened to another guy on another site so i doubt their accuracy.

your vaccum pump sounds like its shot. you should have a puff of black smoke at first when you take off but it should clear up after that.

 

I'll have to see if I can talk the local dealership into using a tech 2 to see what it says, but doubt it, waste gate is wired shut

 

close your wastegate

 

a tech 2 or autoenginuity or carcode will give you the correct tdco offset and will allow you to change it. in the first post you said it was wired open so which is it? if it is infact wired shut it could be that your timing is way out of wack or you have pissing injectors. thats another thing i would check is the injectors to make sure they are the correct pop pressure and atomizing correctly because if not they can cause smoke too. make sure nothing is clogging the intake manifold too.

 

Yea sorry, in first post i meant wired shut, i'm planning on tackling timing tomorrow, just havent had a chance yet

 

well few months back i had chance to get Snapon scanner so call Snapon before brought it and they told me they do not make scanner to do tdco timing for 6.5 all there will do is check computer timing that what they told me

 

why does your truck have to pass emissions?