Be careful when performing
this test. Exhaust gas can
be extremely hot end severe
bums can result.
Put a piece of paper in the exhaust stream for a few
moments with the engine at idle. Then look at the paper
to see if there is any condensed fuel on it. Then smell
the paper to see if it smells like raw fuel. If it smells like
fuel then the engine could be very cold or else it has a
DS level fuel system fault or compression fault.
White smoke for a short time after start up,
especially on a cold day, is a normal condition.
It is caused by incomplete combustion of the
fuel because of low cylinder temperature. It
should clear up in a few minutes. If not you
may have a bed head gasket, cracked block,
or a restricted check valve. Check for
restricted check valve (para. 3-35).