Pulsating FASS

[CrashCade]

Hey guys, what would cause my FASS pump to have a pulsating return on fuel? Sometimes you can hear the pump making a pulsing sound and sometimes it sounds perfect, but the return the fuel always is pulsing or surging. Before I bug Diesel-Dan again, just wondering if anyone has some pointers.

I do not have a fuel pressure gauge right now.

 

[joefarmer]

It could be sucking air.

 

[kino_fab]

When can you hear the pump pulsate? I know my raptor will surge up and down when I start the truck below 50* outside, but thats because of the grid heater kickin on and off.

 

[homewrecker]

^^ same here.Cold mornings,grid heater cycling,cold fuel makes for alot more noises out of the Fass.

 

[MissouriHooker]

My fass does the same thing, has for almost 3 years now. I tryed to get an answer from them but they did nothing, far as i can tell it has not lead to a power loss but my does it all the time doesnt matter what temp. FP gauge is goin in this wk so i guess well see..

 

[CrashCade]

When can you hear the pump pulsate? I know my raptor will surge up and down when I start the truck below 50* outside, but thats because of the grid heater kickin on and off.

^^ same here.Cold mornings,grid heater cycling,cold fuel makes for alot more noises out of the Fass.

Thanks for the suggestions guys. Mine is not a voltage problem though. Of course the voltage surges on colder morning is because of the grid heater, but this is a pump issue. Just not sure if it could be my CP3 or if it is my FASS. I will have to get a FP gauge installed to see what it is affecting, but my pump doesn't do it all the time.

I have been waiting on Floor-It for quite a while now regarding a new CP3, but this is the first time I have ever had a FASS do this.