Fuel Pulsation Damper. What is it?

A fuel pulsation damper is a device used to regulate the oscillation of fuel caused by the injectors opening and closing and smooth this out. Sometimes referred to as a FPD. At this time I do not have a diagram to show you, so you will need to use your imagination as I describe it the best I can. Sorry.

The damper uses a diaphragm to absorb pulses or waves in the fuel. If you could picture what would happen if you were to have a large beach ball in a pool and “bounce” the ball half under the water, let it come up and repeat several times. Waves would form. The injectors opening and closing against the pressure sent by the pump causes the same waves in your fuel system. The damper’s diaphragm is used to absorb these waves and smooth the fuel delivery.

Many people say you do not need the pulsation damper, other will tell you that you do. The ones that say you do not need it more than likely either heard of someone or themselves had an engine fire due to the pulsation damper failing. The ones that say you do need it may have heard stories of an injector failing because there was no pulsation damper. The failure of the injector was caused by the fuel hammering the injector so hard that it failed. I have never personally seen an injector in this state (remember we se A LOT of injectors) and still feel this is an urban legend. If you happen to have an injector in this state, please let me know. I would LOVE to test and analyze it.

If you are running an aftermarket fuel pressure regulator, more than likely there are dampening capabilities built into the regulator. I know for a fact that Aeromotive regulator use this technology but I am not sure about others. Mounting the aftermarket regulator as close to the fuel rail as possible will eliminate any need for additional dampening. The Aeromotive units will regulate the flow by creating a stable and smooth flow.

In short, a pulsation damper does serve a purpose, but is not “necessary”. Many cars like the Mazda RX7 are equipped with a fuel pulsation damper that is prone to failing and causing an engine fire. If you plan on retaining the FPD you must keep an eye on it. Replace it BEFORE it fails and you loose your car to a fire.