I noticed yesterday a decent amount of black smoke even at low rate of acceleration. Little wind and not loaded. I also noticed what appeared to be a little less fuel economy? It was also harder to get it fired? Is timing chain stretching? What my possible causes and fixes? The truck is an '84 6.2 by the way. Thanks Brent

Several things can lead to excessive smoking, but you should check the usuals first. Did you check the air filter, how long has it been since it's been serviced, a dirty air filter will lead to less airflow and more unburned fuel leading to black smoke. The fuel system could also need servicing, your fuel filters may be due for replacement, this could contribute to smoking because of a lack of fuel and you compensating with more petal, and can have an affect on starting quality.

Besides the usual things listed you might have a 1/2 ton truck that is equipped with the 6.2. This version of the 6.2 is equipped with an EGR valve and equipment that is very prone to failure. This will make the engine smoke under medium to moderate load and under full throttle if the valve is stuck. Post back, and we'll tell you how to kill the EGR system.

A little black to grey smoke is normal for a non turbo IDI diesel engine.

I looked under the air cleaner and noticed what apeared to be exhaust smoke at idle and it stayed when I idled i a bit. When is it supposed toopen? Sounds stuck, huh? Brent

Unbolt that egr valve and make a block off plate out of some 1/4 steel and say good bye to your problem, or find a J intake manifold and gain some power while you are at it.:cool2: :grd: