Stanadyne DB Auto Part Advice From Eau Claire Diesel

At Eau Claire Diesel, we offer comprehensive troubleshooting guidelines for Stanadyne DB fuel injection components. Our expert team is here to ensure your diesel engine runs smoothly and efficiently. Read more about your Stanadyne DB injection pump below and discover why we're the trusted choice for diesel enthusiasts. Contact our team today with any questions.

Starts Hard

Verify the air cleaner is clean; just because it looks clean doesn't mean it flows the correct amount of air. If in doubt, replace it. Blowing out air filters does not work because the element usually gets more packed with debris than what you get out.

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

Start by cleaning and charging the battery/s; if the battery is good, check the starter voltage drop. If this is good, replace the starter. We can supply most machines with an OSGR (offset gear reduction starter) to increase cranking speed and less battery draw.

Verify the fuel is fresh and the supply is good, check the lift pump if it has one, and check for fuel suction leaks. Install a clear fuel line from the fuel filter to the inlet on the injection pump. Monitor it for air bubbles, and if bubbles are present, you have a suction or vacuum leak in the supply hose. Keep moving the clear hose closer to the tank until the problem area is found and no air bubbles are present.

Verify and/or change the fuel filters. Do not assume because you just put a new filter on recently that it is good. If you have fuel contamination issues, the filter will be plugged up and need to be replaced. The tank should be cleaned or replaced, as well as all the supply lines. Supply issues can be found with the above testing procedure.

Remove the top cover on the injection pump and look for debris and rust. If you see chunks laying in the pump, the governor flex ring has failed and probably plugged the return fitting in the top cover and return lines. You can remove the fitting and clean it to get the machine to run enough to get repairs made. There is a little plastic ball and spring inside, so be careful not to damage or lose these. Do not continue to operate the unit, as there is no control over the governor weight cage. The cage and pins will bang against each other, causing more metal flakes to be sent through the pump. Remove the pump and send it in for rebuilding.

If all of the above checks out, verify that your compression is good. Good compression range will vary between engines, but you typically want to see 400 pounds of compression and above for a well-running diesel engine. See the manual for your engine for its suggested rebuild tolerances.

Starts Hard Hot

See the above "starts hard" information, and if everything checks out, then the injection pump's pumping head may be weak. When fuel is hot, it gets thin. When this happens, worn pumping heads leak off pressure more easily 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

This may be the same issue as above's "starts hard hot" troubleshooting. The pumping head in the tractor may be getting weak and not able to supply enough injection pressure to fire reset or rebuilt injectors.

Low Power

Verify the fuel is fresh and the supply is good, check the lift pump if it has one, and check for fuel suction leaks. Install a clear fuel line from the fuel filter to the inlet on the injection pump and monitor it for air bubbles. If bubbles are present, you have a suction or vacuum leak in the supply hose. Keep moving the clear hose closer to the tank until the problem area is found and no air bubbles are present.

Verify and/or change the fuel filters. Do not assume because you just put a new filter on recently that it is good. If you have fuel contamination issues, the filter will be plugged up and need to be replaced. The tank should be cleaned or replaced, as well as all the supply lines. Supply issues can be found with the above testing procedure.

If all of the above checks out, verify that your compression is good. Good compression range will vary between engines, but you typically want to see 400 pounds of compression and above for a well-running diesel engine. See the manual for your engine for its suggested rebuild tolerances.

White Smoke

Smoke that is white and burns your eyes is usually a sign of fuel supply and/or early injection timing or restricted air flow and/or low compression. Verify the air filter is new. Try advancing the pump on high-hour machines. If the problem doesn't change, then verify supply and fuel quality. If that is good, test compression, then if that is good, check if the injection pump head is weak.

Black Smoke

Black smoke may occur if the air filter is pluggled, the exhaust is plugged, the turbo is not sufficient for the amount of fuel, and/or the fuel pump fuel setting is set too high for the engine. Properly set the pump and turbo size, and there will be little to no black smoke under the full load.

No Fuel to the Injectors

Check the fuel shut-off solenoid for voltage, and make sure the voltage is not dropping off while cranking/running.

Remove the cover and verify the SOS is moving with power. If it's not moving, replace the solenoid.

If there is no fuel SOS, pull the cover and verify the metering valve under the spindle governor bolt moves freely, and no debris or rust is in the pump. If no issues are found, verify the supply to the pump.

If the supply to the pump is good, check the transfer pump screen where the fuel inlet is to make sure it's clean. If no issues are found, the pump needs to be rebuilt.

Broken Pump Shaft

A broken pump shaft may be from a seized pumping head from poor fuel or the pump is turned up too much for the line and injector size.

Contact Us

Ready to enhance your diesel engine's performance? Get in touch with Eau Claire Diesel today. Our team is eager to assist you with all your Stanadyne DB and other diesel component needs.

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