Dr. Evil

Could it be your guage??

Clunk

My fuel pressure starts at 14psi idle cold then after the motor/pump/fuel warms up, I'll see 15-15 1/2 psi. The clearances must tighten up as parts warm up.

piperca

That's what mine seems to do. Starts out at 13 and, once I give her a good run, she idles at 14 for the rest of the day. When I first put on my Vulcan system she'd idle at 15 ... don't know why it dropped. Hopefully, it's not the LP, it's only got 6k on it!

Shovelhead

After my latest lift pump replacement a couple of months ago, accompanied by a Scotty Smart Fuel setup, I still see 16 @ idle, 14 @ 2000rpm, and haven't pulled it below 10 psi yet @ WOT

ramtd02

I always try too stress this too ppl....

YOUR GUAGE WILL FLUCTUATE THROUGHOUT THE DAY.....regardless of what the pump pressure actually is. Unless you use electric, the mechanical guages use bourdon tubes. These tubes read pressure above atmospheric. However, as we all know atmoshperic pressure changes as elevation increases, or as weather systems move in.

EX. ATM. = 14.7 psi @ sea level.
rainy day i L.A. pressure may only be 14 psi.
that means visually your gauge is gonna read approx. 1 psi lower pressure than it usually does.

The large fluctuations of pressure ie. 4-10 psi. That is more directly a result of either your pump going bad....or you didnt install the needle valve and the pressure regulator is causing these fluctations.

Just my .02
Jon.

piperca

Mine's electric! No needle valve, I was under the impression that was for mechanical gauges ... am I wrong?

ramtd02

nope...not worng. I am getting ready too install an electric guage. What size fittings did you use for yours?? and where did you mount the sender?

piperca

I have a 99 and was able to take it off the post-filter test port. I think you'll need to take it of the shrader at the VP. I think Geno's Garage has a grease gun fitting you can purchase for that.