Carbon in the intake runners...

[BigBurban350]

What is the diagnosis for carbon build up in the intake runners?

Before the valves and even a little in the intake manifold. Note' This a non-egr engine.

 

[BigBurban350]

Ttt

 

[sled_dog]

valve seals would be my guess. Little oil or oil vapor leaking into intake runner.

 

[BigUglyracing]

If I remember right. It is reversion. Unburned fuel in the intake tracts.
If you need more info i think i may be able to find some.

 

[BigBurban350]

If I remember right. It is reversion. Unburned fuel in the intake tracts.
If you need more info i think i may be able to find some.

I am putting new heads on and actually going to tune the fuel injection system this time (eprom programming). I mean even the combustion chambers were caked with carbon. This engine has only 1,500 miles on it.

 

[BigUglyracing]

What tire size / what gears are you running?
Have you been lugging the engine.

 

[BigBurban350]

35" and 4.10 gears on a big ass suburban. I didn't really tune the fuel injection, just added 454 injectors into the 350 TBI unit. My A/F guage said it need more fuel, although I was only using a 1-wire oxygen sensor at the end or full length headers.

I figure richer is better anyways, we'll see what happens with some new heads and a tuned computer chip.