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Trouble shooting:

Starts hard:

Verify air cleaner is clean, just because they look clean doesn't mean they flow the correct amount of air, replace it if in doubt. Blowing out air filters does not work the element usually get more packed with debris then what you get out.

Verify cranking speed is sufficient, If cranking speed is not achieved then injection pump will not supply adequate fuel to start.

Start by cleaning and charging battery/s, if battery is good check starter voltage drop, if good replace starter, we can supply most machines

with a OSGR (Offset Gear Reduction Starter) to increase cranking speed and less battery draw.

Verify fuel is fresh and supply is good, check lift pump if it has one and check for fuel suction leaks. Install clear fuel line from fuel filter to inlet on injection

pump and monitor for air bubbles, if bubbles are present you have a suction or vacuum leak in supply hose, keep moving clear hose closer to tank

until problem area is found and no air bubbles are present.

Verify and or change fuel filters, do not assume because you just put a new filter on recently it is good, if you have fuel contamination issues the filter will

be plugged up and need to be replaced and the tank should be cleaned or replaced as well as all the supply lines. Supply issues can be found with above test procedure. You can also install a vacuum T in the fuel supply line and monitor vacuum from tank to filter and filter to pump.

Verify overflow valve is not sticking open, usually when these stick open you will not hear a squeak sound when hand priming. If they open to early then the galley where the plungers and barrels are will return to much fuel back to filter/tank and it will not have enough fuel in galley to complete a full pumping stroke usually you will see the supply pump peak pressure drop if this over flow valve is bad.

If all of the above checks out, verify that your compression is good. Good compression range will very between engines but typically you want to see

400lbs of compression and above for a good running diesel engine. See manual for your engine for suggested rebuild tolerances


Starts Hard Hot:

See above (Starts Hard) if all verify then injection pump may be weak when fuel is hot it gets thin, when this happens worn plungers and barrels leak off pressure easier and do not supply the injector the full amount of pressure until engine RPM is sufficient for the pumping head to have enough RPM to make the pressure the injectors require and then it will run.

Injectors rebuilt and now starts hard:

Same issue as (Starts Hard Hot) Pump may be getting weak and not able to supply enough injection pressure to fire re set or rebuilt injectors.

Low Power:

Verify fuel is fresh and supply is good, check lift pump if it has one and check for fuel suction leaks. Install clear fuel line from fuel filter to inlet on injection

pump and monitor for air bubbles, if bubbles are present you have a suction or vacuum leak in supply hose, keep moving clear hose closer to tank

until problem area is found and no air bubbles are present.

Verify and or change fuel filters, do not assume because you just put a new filter on recently it is good, if you have fuel contamination issues the filter will

be plugged up and need to be replaced and the tank should be cleaned or replaced as well as all the supply lines. Supply issues can be found with above test procedure.

If all of the above checks out, verify that your compression is good. Good compression range will very between engines but typically you want to see

400lbs of compression and above for a good running diesel engine. See manual for your engine for suggested rebuild tolerances

If all checks out then pump may have worn plungers and barrels or leaking delivery valve gaskets

White smoke:

Smoke that is white and burns your eyes is usually signs of fuel supply and or early injection timing, restricted air flow and or low compression, verify air filter is new. On some p pumps we have seen the gear slip on the pump shaft and timing becomes late, re set the timing of the engine and pump by pulling gear off pump and re install with timing pins in engine, brake clean gear and shaft of pump and re install pump gear and torque to spec.

Try advancing the pump on high hour machines, same process as above, lock engine pins and pop gear loose, mark crank shaft balancer by timing finger and back motor up the width of the factory timing line and re test, keep doing so until engine starts runs correct if problem doesn't change then verify supply and fuel quality, if good test compression if good injection pump is weak.


Black Smoke:
Air filter is plugged, Exhaust is plugged, Turbo is not sufficient for amount of fuel and or fuel pump fuel setting is set to high for engine.

Proper set pump and turbo size will have little to no black smoke under full load.

Some p pumps have an aneroid above the governor housing, check to make sure this supply line from engine intake isn't leaking or broken, this uses turbo boost to push down the aneroid diaphragm and let the fuel rack in the pump move further to supply more fuel to the injectors. If all is good verify fittings of the tube/line are not plugged with debris and check turbo boost pressure, if no boost pressure then check turbo for issues. (intake restriction, back pressure to high ect.)