Rich idle then stalls

[Coolice232]

Just finished rebuilding the engine all stock , the car starts then throws black smoke(rich) then stalls , checked timing changed many sensors (map , tps , water temp)
Finnaly i bought a scanmaster gague and installed it ,
What i found is that i am having a very unstable readings( switch on engine off) its going crazy up and down in value
Who can help me with that ? Could it be the pcm ?

 

[2500avalanche]

Where are you located? I spent a lot of time this past spring understanding the scanmaster.
What is the build you have (type of map), type of chip, etc.
Hope I can lead you in the right way!

 

[Coolice232]

Everything is stock , got the car with bad piston rings . So i did a complete rebuild , and failed to start the engine , it starts for few seconds with black smoke(very rich) then stalls
Stock map stock injectors stock everything
Now when i installed the scanner i realized that my (tps,boost, air temp) sensors have unstable readings (switch on engine off) i dont think thats notmal
Maybe a bad pcm or short in harrness. I don't know

 

[wildphil]

Is it throwing any trouble codes.

 

[proptop]

Randy,
Make sure all the grounds/contact points are cleaned. Did you put on a fresh coat of paint when the motor out is so that could be it. Back in the day when I replaced the motor in the GN had the same issue. Could be that simple.
Bob

 

[Coolice232]

Randy,
Make sure all the grounds/contact points are cleaned. Did you put on a fresh coat of paint when the motor out is so that could be it. Back in the day when I replaced the motor in the GN had the same issue. Could be that simple.
Bob

Yes i did paint the block ,,, i will check that