Is there an altitude sensor? White smoke in Mountains.

[RyTaWaY]

85 6.9 4 speed manual, compression front 5 are 400 back 3 are 380

When towing 8000 pounds above 3500 foot elevation up a grade it starts blowing ALOT of greyish smoke even though I only seem to be giving it around 1/2 - 3/4 throttle in 3rd (4 speed manual).

I am passing big rigs just fine but it got up to 1/2 temp on the dial and the overheat light came on.

And now I noticed that its blowing lots of white smoke when the engines cold especially idling or decelerating and sometimes when giving the gas starting up a little hill after coasting for a while from around the 8000 foot elevation to around the 3500 elevation.

When I get down below 3500 feet its fine and blows little or normal smoke when floored and the smoke looks just like any other diesel. But by that point the engine is at normal operating temp.

I changed the fuel water filter and just reciently had a professional install a new injection pump all new injectors added the 7.3 style fuel water filter with lower threaded bleeder, and all new glow plugs

Thanks everyone...

[RyTaWaY]

The truck starts quickly warm or cold but recently when cold at high altitude it ran fine for the first 15 seconds or so then started idling rough and blowing a ton of white smoke. Thats when i replaced the fuel filter. The old filter did have alot of redish little dots in it. Now it hasnt done the rough Idle and didnt start blowing white smoke until I decelerated or gave the gas after coasting for a while. Dont know if this is related but it doesnt seem to slow down much when I downshift.

[M.L.S.C.]

Hmm, something odd is going on - on your initial question, no, there's no altitude sensor on your truck, so you can rule that out as a potential culprit. I've had my truck blow tons of white smoke and run rough, but that's cause for a few moments she was running on antifreeze and WMO (which is why one should always check their WMO batches). When these trucks are starving for air they usually smoke black as a result of the overfueling, a white smoke is often an indicator of either coolant being burned off, or timing that is way off.

[Joe Mc]

Half temp? I guess that you have the stock gauge and not a real gauge.
For towing I would install 3 or 4 gauges, water temp, oil pressure, pyrometer and maybe a voltage gauge. Voltage in a better way to watch your battery state and the pyrometer is needed with your elevation changes. With my truck at 8,000 feet my exhaust temp can hit 1,200 degrees in a blink, while empty. I like the triple-pod on my A-pillar in my truck so much, I installed a one in my Toyota Camry. Unfortunately no one make a triple or double pod for your 85 or my 86 anymore. But one for a 92 will fit if you cut the top and bottom ends off. This has been written up way back on this site.

Cooling off while idling or easing down a long grade is common with a diesel and will cause white smoke. Check your thermostat, it should be a 192 degree unit from Ford or International ONLY.