GMC 1994 Yukon Owner's Manual page 255

NOTICE:
If there is water in your diesel fuel and the weather is warm or
humid, fungus and bacteria can grow in the fuel. They can
damage your fuel system. You'll need
a
diesel fuel biocide to
sterilize your fuel system. Your dealer can advise you if you ever
need this.
If your fuel tank needs to be purged to remove water, see your
dealer or a qualified technician. Improper purging can damage
your fuel system.
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Running Out of Fuel (Diesel Engines)
If the engine stalls and you think that you've run out of fuel, do this:
First, open the fuel
filter air bleed valve.
If there is air, then you
are probably out of
fuel.
To restart your engine:
1. If you're parked on a level surface, add at least two gallons of fuel.
However, if you're parked on a slope, you may need to add up to five
gallons of fuel.
2. With the air bleed valve open, turn your ignition key to "Start" for
10 to 15 seconds to crank (but not start) your engine. Wait one minute
between intervals of cranking to allow
the
starter motor to cool.
Overheating the starter could damage it. Keep doing this until you can
just see some clear fuel at the air bleed valve. (If, during this step, the
engine starts, turn the ignition off and close the valve before restart.)
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