pwjackson
Full Access Member
Got a NA 6.9 with complete new fuel system. I have noticed when driving that I get nice black coal smoke at low rpm but when I get in the 2500 to 3000 rpm rang and getting on it down the road I have a grey smoke. Could this be that my timing is to far advanced? I have been getting around 15 to 16 mpg so I figured it was timed pretty close. I had a well known shop time it for me, didn't know that if with the low sulfur fuel and the slightly advanced over oem timing would cause the lighter smoke at higher rpms.