txfdr2

iTrader: (5)

My fuel system consists of:

Supra pump (2k miles on it)
New OEM filter
FFE rails
id 2000 sec
id 725 prim
aeromotive FPR (EFI w/ boost reference)
Mechanical gauge on the side of the regulator
-6 lines and fittings in the engine compartment, stock/oem back to the tank.
It is run in a series, the regulator is correctly hooked up. All emissions were deleted off the car during the build.

I just got my engine started for the first time after building it. All fuel components are new. No kinks in the lines. But the gauge bounces like crazy when I start the car. So I try to set my pressure to 43.5 but the gauge just flutters extremely fast between 40 and 45 psi.

Anybody have any ideas? I took the regulator apart, didn't see anything stuck in it. Car idles great. I can crank the pressure up and turn it down, but it flutters no matter where I set it.

Also, When I shut off the engine, the fuel pressure stays constant (no fluttering) and slowly starts to fall off.

RotaryEvolution

iTrader: (30)

pick up an oil filled gauge, it will dampen the fluctuations(which are fairly normal).

cheaper the gauge the more it will bounce.

there should be a FAQ on this already, i see unbuffered gauges installed rather commonly and i hate seeing people waste money/time on them.

vrx8

iTrader: (18)

try to lower the pressure some more. A buddy of mine had one and it will do that if the pressure was to high.

But an oil filled one is the way to go

txfdr2

iTrader: (5)

MS 0-60 PSI Liquid Filled Mechanical Gauges from Marshall Instruments

copy/paste: Silicone Filled for Vibration Dampening Acrylic Lens

Thats the gauge i got. Which one are you having good luck with?

I can fully adjust it low or high and at still flutters.

RotaryEvolution

iTrader: (30)

are you sure it is the liquid version? you should see a tiny bubble of air inside the gauge. i've never seen a liquid filled marshall gauge bounce around like describing here.

if it is damapened(oil filled) then you may have a volume issue with your pump. ie loose seal on the pump allowing fuel to bypass, low pump voltage, blocked up fuel filter or just a crap pump.

txfdr2

iTrader: (5)

I will dig in more tonight after work. Yea, I am positive it is liquid filled. I will start with voltage, maybe I missed a ground somewhere when putting this car back together. Ill start with a voltage check. I just looked at my "first start" video and it was bouncing. I noticed the bouncing about the 3rd time I had started it.

txfdr2

iTrader: (5)

well, slight update. Problem isn't fixed, but I took another look at my gauge. I did not get the part number I ordered. I paid for the one I listed above, but received a non-fluid filled, cheaper gauge. The vendor claims it was a shipping mistake and is taking care of it. Hopefully that will solve this problem.

Thanks for making me question it ... I would have not noticed otherwise.

RotaryEvolution

iTrader: (30)

makes sense, even most issues i listed above will be dampened by the fluid filled gauge.

chaos7

iTrader: (2)

I've had a similar issue before on another car as the fuel pump was going out, aeromotive fpr, walbro pump that was getting super noisy. The needle juping went away after i replaced the pump.