Fuel Pressure Pulsing with Liquid Filled Guage?

[turboman1]

I have put a new lift pump on it and have a summit liquid filled guage and it still pulses the needle on the guage and travels with engine rpm. Around 2700-3000rpm it levels out and holds. Is this natural even with a liquid filled guage or do you think I have a cam lobe wearing out or something restricting the flow a lot?

Thanks
Adam

 

[White Knight]

The valves needs a snubber to dampen the pulses generated from the pumps. A needle valve works great. Put a snubber of some sort on it and see what happens.
And fuel pressure should increase with engine rpm since the pump is driven by the engine, that's normal.

 

[turboman1]

Well i can't really tell with great accuracy the fuel pressure at idle but at wot it stays at 40 psi at about 2700 rpm when the guage stops pulsing.

That is the pressure with the stock overflow spring + a ball point pin spring. Does that seem kind of low?

Adam

 

[White Knight]

Factory specs are 17 - 22 psi at idle and of 25 - 35 psi at 2500 rpm (no load). Its hard to say what ideal pressures would be with a pen spring added as that depends on the condition and rate of the springs.

40psi at 2700 is plenty. Get a snubber and see what it does under load.