Whats the difference?
 

Just thinking, pressure is pressure? So what is the difference in a fuel pressure and oil pressure guage besides the name and cost. Could an oil pressure guage be used as a fuel pressure guage on a diesel engine with the same accuracy? Diesel is oil, correct?:s:

I am using a speedway motors oil pressure digital gage for my fuel pressure, the gage and sending unit cost less then most sending units alone. the sending unit has acted up and a replacement is about '$11.00 ED

Yes, pressure is pressure, the gauge dont care how its made or whats making it.

We use 0-30psi mechanical gauges that you would buy at grainger or any industrial supply, plumb them with some hose, easy fuel pressure gauge for about 20 bucks.

But ....I would only use a liquid filled one for oil or fuel.

Theres no difference - nthe intarnals are exactly the same. I ran a mechanical/industrial type pressure guage for quite some time before I got an actual fuel pressure guage. The only real problem was that you couldnt see it at night.

We do use liquid filled gauges now, we had an $5.00 el-cheapo gauge from autozone or somewhere die from the pressure pulses from the injection pump.

I think a good (non)-liquid filled gauge would work fine, but the price differance is only few dollors.