Im going to install the ecs tuning fuel pressure gauge tomorrow and was wondering what my fuel pressure should be reading.. Another question is im running the franken turbo but still on a apr ko3 tune should my pressure be diffrent than stock and should i pick up an adjustable fuel regulator. Thanks

 

stock fuel pressure is 4 bar, so that means youll see 4x14.7 for 58.8 psi at the rail. if your running a frankenturbo, fuel pressure will be the same. the tune has nothing to do with the pressure you see, although a frankenturbo tune may call for a lower pressure. only the fpr will adjust the pressure at the rail

 

Just installed the fuel pressure gauge and a new fuel filter and im reading only 49psi. What would be the reason its running that rather than 58 like you said.

 

Fuel pressure is supposed to be measured relative to ambient pressure. Our FPR (fuel pressure regulator) system is a rising-rate system, in other words it relies on intake manifold pressure to adjust the fuel pressure.

To measure your fuel pressure relative to ambient pressure, simply disconnect the vacuum line from the FPR (pinch the line as you're holding it to prevent a vacuum leak) and measure your fuel pressure. When you're done measuring the fuel pressure put the vacuum line back on the FPR.

Assuming that you don't have any vacuum leaks, when your engine is at idle you should be seeing about 20-21 in HG. This translates to about 10psi. So if your engine is putting a 10psi vacuum on the FPR which should be at 4bar (4 x 14.5 = 58psi), then you should see ~48psi at idle.