Fuel Pressure "Spiking @ Idle and long cruise.

[Gil2264 0]

New fuel pressure problems...I used to have problems with sudden pressure drops, so Installed a Raptor 100 Lift pump. It's worked quite well up until my last 300 mile trip. Now my fuel pressure spikes (up to 30 psi) on long low throttle cruising, and at idle. The electronic fuel pressure sender (Glow Shift) is isolated from the VP inlet by a 16" grease gun hose. Would this seem like enough of a "Snubber", or should I get a needle valve? A buddy of mine has a mechanical fuel pressure gauge. We'll hook it up in a few days and compare readings. I just wondered if anyone else has ever had problems with a Raptor 100 spiking. Idle fuel pressure is set at 15-17 psi.

[Mopar1973Man 6,229 5 Vehicles]

Yeah you need a snubber / needle valve the grease gun hose is not enough to protect from water hammering... Even 10 feet of 1/8 air line running into my cab isn't enough... The electric sender might already be damaged..

[flatbed56 0]

I just received a snubber valve and sending unit from glow shift. I called them, about my gauge back and forth from 18lbs to 30. They said the snubber takes care of the different fuel pressure and that the sending unit is going out. Something about dodges, not sure why. Glow shift was very helpful. I hate to replace the sending unit, I always get diesel on me.

[AH64ID 1,038 1 Vehicles]

Try draining the line by draining the filter bowl. Its what I do when I work on my fuel system and it really reduces the spillage. Good luck and hope that fixes it.