Hey guys! I got an issue I could use some help with. Recently I installed rear disc brakes on my truck and while I had the truck out of service waiting on parts I figured I'd finish installing some new fuel lines and AN fittings on the truck. The brakes turned out great! Seems like my braking improved 50%, but the fuel system now has a bad pulse. My fuel pressure gauge started out bouncing between 18 & 20 psi. Once I started driving it started pulsing worse. A little further down the road and it started bouncing from 0 - 60 psi. Oh I normally have about 16 psi before the recent work and its a 2nd gen. piston pump w/ regulator. Anyone else had this issue? Could I just still have air in the lines? I wont be near a computer to reply till tomorrow. Thanks in advance!

 

The bouncing is normal because the pump only makes one stroke every two engine rotations. You weren't seeing it at first because there was a bunch of air in the gauge line damping out the pulses. Get a needle valve or a snubber so you get a smooth reading before you panic. If you were running for a while with no protection for the gauge you may have trashed it, as you can imagine that jumping around i not good for the gauge.

What regulator are you running?

 

I don't know what brand the regulator is. I bought it, the pump, the hose, and some of the fittings from a fella on the forum. It's just a simple black "fitting" with a spring and ball inside it. I knew the piston pump pulsed, but I thought the regulator would smooth it out once it got to that point since its supposed to hold a set psi. Thanks for the clarification and tip on the needle valve or snubber. Who is the best to pick one up from?

 

Your local hardware store will have a needle valve. McMaster-Carr is a good source for a snubber.