Sons 85 Burb 6.2 Smoking

[SteveMc]

After seeing my 87 Suburban, the soninlaw started looking and sure enough he found an 85 with full maint. records and priced right. He was happy.

Now he isn't so happy. Its started to smoke. Not oil smoke, but fuel. I have given him what info. I've seen on this page--CDI valve, timing, air filter, clogged return fuel line, EGR system.

This problem has come on fast and is now making soot on startup. Has 200k miles and uses no oil, 30k on IP.

Any thoughts or similar experiences please let him know as I have talked him into signing up for this page. He should be on in a dayor two.

Thanks SteveMc

[SteveCO]

The color of the smoke can be a clue, white smoke is usually unburned fuel, or cold conditions so combustion is incomplete, black under load is unburned fuel as well but combustion temp is higher, blue is usually oil. What color and under what conditions are the two questions to ask. Regards,
Steve

[SteveCO]

Also, my old 83 1/2 ton had the white smoke at start-up begin suddenly and then worsen over time, eventually the injection pump failed. This took about a month from the time I first noticed the additional smoke. Earned that truck the soubriquet "ol' stinky" ;)

Recently had white smoke show up again but it was a plugged return line and the engine would not run longer than a few seconds. Good luck,
Steve