Engine FAQ

Q: With the fuel pump on, my fuel pressure gauge shows a different pressure than the original setting. Should I adjust the regulator until the gauge matches the original setting?
A: No, most gauges are very susceptible to damage caused by vibration normally experienced in race cars. If your gauge reads differently now, it’s more likely that the gauge is reading incorrectly. We recommend leaving the regulator set at its original setting. It is helpful to have a “master gauge” that is used to check the pressure at the shop during the week. Compare the reading of the master gauge to the gauge on the car to determine if there is a fuel system problem.

Q: If the fuel pressure gauges fail so frequently, why even use one at all? Wouldn’t it be better just to check the pressure weekly at the shop?
A: The gauges in the cars are used for a diagnostic purpose. If your car loses power under high load or RPM, a quick look at the pressure gauge will allow you to differentiate a fuel system problem from something else. A 10psi or more drop in fuel pressure usually indicates a partially clogged fuel filter or failing fuel pump.

Q: The car loses power at the end of the straights. I noticed the pressure gauge dropping at least 10psi also. How do I know if the filter is clogged or if the pump is bad?
A: A faulty fuel pump is generally identifiable by simply listening closely. If the whine of the pump can be heard over the sound of the engine idling, the useable days of the pump are numbered. A clogged fuel filter can also cause added strain on the pump causing it to emit a loud whine.

Q: I installed a new fuel pump but the fuel pressure gauge displays 0psi and there is no fuel pumping through the return line into the tank. I can hear the pump running. Is it possible that the new pump is faulty also?
A: We find it rare that new pumps are faulty from the manufacturer. First, check that the wires to the pump are connected to the proper terminals on the pump. If the wires are hooked up backwards, the pump will spin backwards. This causes the pump to suck air from the return line and could cause permanent damage to the new pump. The pumps are labeled + for positive from the switch and – for ground. Check the orientation of these wires before sending your pump back.

Q: I cleaned my fuel filters with brake cleaner and replaced a noisy fuel pump but the fuel pressure still drops under high RPM. What else could be the problem?
A: Brake cleaner will not completely clean the 25micron filter element. Ultrasonic cleaning is the only recommended cleaning method. To quickly diagnose a clogged filter, remove the filter from the car and blow compressed air through the filter to clear the fuel from the element. Hold the filter to your mouth and blow into the inlet of the filter. You should be able to do this with little to no effort. If the filter requires more pressure to blow through, it is at least partially clogged and requires ultrasonic cleaning.

Q: How can I tell which fuel filter is the 25 micron and which is the 70 micron?
A: The 25 micron filter has a much finer mesh than the 70 micron filter. By removing the filter cartridge from its’ housing, the difference between the filters can be seen.

Q: How often should the fuel filters be cleaned?
A: With a new fuel system, the filters should be cleaned after every race for 3 races. After that, the filters should be ultrasonically cleaned every 15 races.

Q: Why is it important to have my fuel injectors flow balanced?
A: With flow balanced matched injectors the engine is able to produce an equal amount of horsepower from each cylinder. This enables the engine to run smoother and produce more horsepower throughout the RPM range.

Q: How often should my spark plugs be changed?
A: We recommend new spark plugs every 10-15 races and every time an engine is rebuilt.