Frequently Asked Questions

Do I need to use fuel additive with my diesel fuel?

If you buy your fuel in a variety of locations, it is a good idea to use a multi-purpose additive such as Stanadyne’s “Performance Formula.” Make sure that the additive addresses lubricity. If you consistently buy your diesel from the same source, talk to your supplier to find out what additives (if any) are already in the fuel. You may not even need further additives.


How do I know if my injection pump is failing?

In many situations the injection pump is removed before proper troubleshooting is done on the engine. Make sure that the fuel supply is adequate and that there is no air in the system. Talk to someone with a lot of diesel experience, such as an authorized fuel injection repair shop, to get ideas of what to look for. If you are not familiar with the fuel system, find someone who is. There are a wide variety of fuel systems, so each system has to be approached differently. An experienced diesel technician will know what questions to ask you. Make sure to tell the technician about all of the symptoms and any history on the engine and fuel system. Good communication is the key to a correct diagnosis.


My diesel starts up and then dies in the morning. I then have to crank it to get it to start. What is the problem?

This has been a very common problem with diesel pickups, cars, trucks and other applications where the tank is lower than the pump. This problem is usually worse the longer the engine has been shut off. What happens is the system is not tight, and air is able to enter the system and the fuel drains back to the tank. Fix any visible leaks first, if this doesn’t work you may want to pressurize the system. Another quick fix is to add a positive seal one-way check valve to the system. Depending on the fuel system, your fuel injection or diesel specialist will be able to point you in the right direction. Unless the injection pump has an obvious leak, it will seldom cause this problem.


My diesel will not even try to start in the morning, but starts great when the engine is warm. Is my pump going bad?

If you have an engine with glow plugs, verify that the glow plug system is working. Other causes for this condition are low compression, poor cranking speed, incorrect pump to engine timing, poor nozzle atomization, and poor fuel. There are other possibilities, but rule these out first. This is usually not a pump problem.


My diesel starts hard when it is hot, and better when it has cooled down. Or, it starts hard in all conditions. Is my pump bad?

There is a good chance that this will be a pump problem. There are a few other things it could be, such as cranking speed, fuel quality, and timing that should be considered.


How often should I clean my injectors and nozzles?

You can refer to your vehicle or engine manual, but we normally say “if it ain’t broke, don’t fix it.” Normally you will have symptoms such as, excessive smoke, rough running, poor fuel economy, or some other symptom if your nozzles need attention. Nozzles should always be tested if any major engine work is done, or an engine failure has occurred. We would also recommend you have your nozzles tested if the pump is being overhauled.


What causes turbo failure?

There are many causes of turbo failure. Theoretically, a turbo should last indefinitely if it is supplied with plenty of clean oil, debris is kept out of the wheels, it is not abused by overfueling, and is not subjected to hot shutdown. Most failures that are a the result of an incorrectly assembled or defective turbo will occur within the first few hours of operation. After that time period, the failure is usually the result of something other than the turbo itself. If you have a failure right after installing a rebuilt turbo, it is very important to determine the cause of the failure before installing another. If the problem is not corrected, you can look forward to another failure. Your turbocharger specialist can assist you in determining what to look for. A failed turbo will generally tell the story once it has been analyzed. Your original turbo may have lasted 5000 hours but failed in the last 1 hour of operation.