White smoke when at low throttle/coast on descents

Michael Alvernaz

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1990 f250 with 7.3 idi, 141k, mostly stock

When going down long and straight descents, I have the throttle very lightly down, just enough to fully engage the transmission and the truck has a lot of mostly white smoke coming out of the exhaust. This will also happen when coasting in gear, but not if I have it in neutral.
If I was coasting in gear, and then press down on the throttle again, if I lightly press it will feel like it’s partial firing, or a little clunky for a couple seconds with some white smoke. if I press most the way down on the throttle there is little smoke and is much smoother.
This is more common at high elevations, I live in the winter at between 7-9k and cold, so some issues due to air/fuel mix being off are to be expected, but I haven’t seen my symptoms details elsewhere.
 

Farmer Rock

just a fella' without a 10mm socket
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With 141k on the original injector pump and injectors they most likely need replaced.That white smoke in your case would indicate they are worn(assuming timing is set correctly)



Rock
 

Michael Alvernaz

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I was thinking of restricting the fuel and advancing the timing to help with the altitude issues, would this be worth doing before I replace all the injectors? Or is 141k past the injectors normal lifespan and should be done to prevent bigger problems
 

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