Diesel injectors can suffer from the same kinds of ailments as gasoline injectors including varnish deposits, clogging, wear and leakage.  Beacuse diesel injectors operate at much higher pressure than gasoline injectors, their opening pressure can drop over time.  Up to 300 psi is considered acceptable, but more than 300 psi means the injectors should be replaced or reset back to their original operating specs.

You may find that one or more injectors need nozzle tips.  Replace them with NEW BOSCH NOZZLES, not reconditioned nozzles.  Reconditioned nozzles may cost less, but often do not perform.  As the spray holes wear, spray pattern and fuel atomization are affected as well.  This in turn, can have an adverse effect on fuel economy, noise and emissions.  Used nozzle tips also lose their temper from long-term exposures to operating temperatures, which means they wont hold up over the miles like a new or fully rebuilt injector.

WHITE SMOKE

Dirty injectors will lean out the air/fuel misture, causing a loss of power, rough idle and sometimes, white smoke in the exhaust.  White smoke usually occurs when there is not enough heat to burn the fuel.  The unburned fuel particles go out the tailpipe an typically produce a rich fuel smell.  It's not unusual to see white smoke in the exhaust during cold weather until the engine warms up.  Bad glow plugs or a faulty glow plugs control module can cause white smoke on engine start up.  If white smoke is still visible after the engine has warmed up, the engine may have one or more bad injectors, retarded injection timming or a worn injection pump.  Low Compression can also be a source of white smoke, as can air in the fuel system.

BLACK SMOKE

Leaky injectors will richen the air/fuel mixture and cause black smoke.  Black smoke is usually a signal that there's too much fuel, not enough air or injection pump timing is off.  One of the most common causes of the condition is an air inlet restriction.  The cause may be dirty air filter, a collapsed intake hose or even an exhaust restriction.

BLUE SMOKE

Excessive blue smoke indicated problems from low engine compression and.or worn piston rings, scored sylinder walls or leaking valve stem seals.  The blue smoke is caused by crancase oil entering the combustion chamber and being emitted after partial combustion through the exhaust.