TESTING AND ADJUSTMENT
6. Check the fuel pressure in the fuel system. Fuel
Either too much fuel or not enough fuel for combustion
pressure at FULL LOAD must be 30 ± 5 psi (2.1 ± 0.4
can be the cause of a problem in the fuel system.
To check fuel pressure, remove plug (1) that is just
Many times work is done on the fuel system when the
behind the fuel shut-off solenoid on the top cover of the
problem is really with some other part of the engine.
fuel pump housing. Install the necessary fittings and a
Finding the source of the problem is difficult, especially
gauge to check fuel pressure.
when smoke is coming from the exhaust. Smoke coming
from the exhaust can be caused by a bad fuel injection
nozzle, but it can also be caused by the following:
Tools Needed: 8S2242 Nozzle Testing Group.
8S2245 Injector Cleaning Tool Group.
b. An overload at high altitude.
Burning of too much oil.
8H8505 Combination Wrench.
8H85602 Combination Wrench.
d. Not enough compression.
1. Check the fuel level in the fuel tank. Look at the cap for
5/64" Hex Wrench.
the fuel tank to make sure the vent is not filled with dirt.
An easy check can be made to find the cylinder that is
2. Check the fuel lines for leakage. Be sure the fuel
misfiring, or running rough, and causing black smoke to
supply line does not have a restriction or a bad bend.
come out of the exhaust pipe.
3. Install a new fuel filter. Clean the primary fuel filter if
Run the engine at the speed that gives misfiring.
the machine is so equipped.
Loosen the fuel line nut at a fuel injection pump. This will
stop the flow of fuel to that cylinder. Do this for each
4. Remove any air that may be in the fuel system.
cylinder until a loosened fuel line is found that makes no
difference in engine running. Be sure to tighten each fuel
5. Check the flow of fuel from the constant bleed valve.
line nut after the test before the next fuel line nut is
The flow must be a minimum of 1 pint (0.47 liters) in one
loosened. Check each cylinder by this method. When a
minute at full load speed.
cylinder is found where the loosened fuel line nut does not
make a difference in engine running, test the injection
pump and injection nozzle for that cylinder.
Temperature of an exhaust manifold port, when the
engine is running at low idle speed, can be an indication of
the condition of a fuel injection nozzle. Low temperature at
an exhaust manifold port, is an indication of no fuel to the
cylinder. This can possibly be an indication of a nozzle
with a defect. Extra high temperature at an exhaust
manifold port, can be an indication of too much fuel to the
cylinder, caused by a nozzle with a defect.
CAUTION: Do not test or disassemble nozzles unless you
have the correct service tools.
Before testing a fuel injection nozzle, remove any loose
carbon from the tip of the nozzle with the 8S2258 Brass
LOCATION OF PLUG
Wire Brush. Remove the carbon seal dam. Clean the
groove for the carbon seal dam and the body of the nozzle
below the groove with