Light Gray smoke

[12 valve owner]

Hi, I have an automatic 96 12 valve with a few mods like #10 fuel plate, four inch exhaust, k/n intake, cfm intake manifold and boost elbow fitting. The problem is when it is warmed up after 20 minutes or so of driving when I slow down to thirty miles per hour and floor it usually black smoke bellows out of the exhaust but lately it has been light gray. I have no EGT gauge yet but I have one on the way. Truck runs awesome with over 170,000 miles and never has had any issues mechanicaly. My truck has never done this Im not sure if I need to make a couple of adjustments since I added The fuel plate.

 

[Mike]

Bellowing black smoke is an indication of way overfueled (which you would expect with a modified pump), gray smoke means that your A/F ratio is more in line with what it should be. Not sure why you are getting less fuel or more air than you were before.

 

[MMeier]

Sounds pretty much normal for a #10 plate. Bumping the timing up to 15.5-16* should help more... get your gauges before you hurt something expensive !!