[Shotimes] Another Stupid Question

[krazgeo@comcast.net]

 -------------- Original message ----------------------
From: Peter Maggiacomo <gtsrider@yahoo.com>
> Are all Gen I and II engines dirty runners?
> My tail pipes are black, while most other cars I see
> in parking lots have a greyish color. 

First of all, there are no stupid questions, just stupid answers.

Back when there was lead in gasoline, a proper air-fuel mixture left a brownish gray deposit on the tailpipe, while a black deposit indicated too rich a mixture.
 
Today, there is no lead, so all pipe residue is black (or various shades of it).  If there is relatively thick, loose black carbon in the pipe, which you can easily rub out with your fingertip, the engine is running rich.  If the residue is thin, and not much comes off on your finger, you have a good mixture.

George