Fuel Pump??

[mattatk]

G'day All,
Had the stethoscope on engine yesterday & noticed a pronounced ticking sound in the brass (?) fuel lines either side of the engine. Could also hear it with stethoscope on adjacent air plenums.
Is that a normal sound in the fuel lines? Or could it be some other vibration (?) that is shaking the engine parts around?
Thanks in advance,
Matt

[JFP in PA]

It's your injectors firing............

[mattatk]

Aha, thought it might've been but being new to this I thought I better check!! Thanks