There are some noticeable signs of troubled fuel pump work in diesel systems. You may check them up using the list below.

• Poor acceleration. The worn pump is not able to provide needed amount of fuel with appropriate pressure at the moment of acceleration. So you may feel like car is struggling with the speed increasing.
• Jerks and sputters at high speed. Pump is not able to keep proper pressure at maximum need. So sometimes engine get low amount of fuel in cylinders which causes noticeable jerks.
• Noticeable loose of the power when driving uphill. Under the load the engine demands more fuel to keep up performance. If pump is not able to provide it in time the car will lose its thrust and slow down. 
• Unexpected acceleration. Worn pump may sporadically change the inline pressure in the system even at stable speed. The pressure may drop, but also get a bit higher for few seconds. Then you feel like your car is accelerating though you didn’t change the position of gas pedal.
• Hard start up. The low pressure in the system may be one of reasons of long and struggling engine start up. There might be other reasons, but in combinations with some symptoms described above the hard start is a clear sign of high pressure fuel pump troubles.
• HPFP compound by Atomium is designed to restore worn parts of fuel pumps. It is not a pump lubricant additive or a pump cleaner additive. Other fuel additives should be used to clean up and lubricate diesel fuel system – such as for example SDA additive. In case you assume the fuel system in your vehicle may be heavily contaminated it is reasonable to clean it up first (using two or three tanks of fuel with SDA additive) and then use restorative compound HPFP. Clean surfaces are getting restored more efficiently.
• HPFP compound is safe for diesel fuel injections. It doesn’t disturb shat-off needles or other elements. It also doesn’t contaminate it. On the contrary in case of heavily worn needle the compound is able partially restore it.