Fuel pressure guage

[madkaw]

I am wanting to install a fuel pressure guage in my car. I thought it would be as easy as picking out one on the Summit Racing site, but I guess I need to be schooled first. I have noticed that some guages are for OUTSIDE installation only. I want to install this in the clock slot, so it's going to be inside the car. I would like to see some other installations of a fuel pressure guage including where you tie into under the hood. I will be using this on my SU set-up right now and then on my Mikuni's.

I want to verify fuel pressure at all times under load----or is that necessary? I have an aftermarket mechanical pump and I question it's ability to supply enough fuel pressure.

[jaltman]

I would say its unnecessary on a permanent basis. Low pressure mechanical pumps for carb systems need minimal pressure, 2-3 psi is normal. Just enough to keep the float bowls full. Absent a bad pump, 2 or 3 psi at idle means its fine. Pressure wont change much, but it might fluctuate some as the float valves open and close.

FI systems, which use a much higher pressure, 36 psi in my FI V8, but again, if the pump and regulator are working, its working. Hi Pressure FI systems have check valves in the pumps to maintain pressure between runs, so you can test for a bad check valve.

I have an external meter, but only use it from time to time, last time to check for a slow leak in my FI car in a hidden area under the plenum on my FI V8. I could smell gas, but not see it. Since pressure fell off when turned off, i removed the plenum to find an injector hose cracked and leaking.

A permanent meter for an FI system might provide a bit more entertainment value, but, ultimately, you have enough pressure and the car is running, or you are sitting on the side of the road looking at your zero pressure.

[Zforce]

You can put a fuel pressure gauge inside the car using an isulator type pressure gauge. The fuel pressure works against a diapham that moves a non flammable fluid through the line to the gauge so no fuel is ever inside the car,autometer makes one.