CHECK 1, 2–CHECK 1, 2
If you’re at all familiar with the late-’80s to early-’90s Mustang EFI systems, you’ll know that Ford provided a small check valve you could screw a fuel pressure gauge to in order to verify fuel rail pressure. When upgrading to an aftermarket EFI solution, generally it is common practice to install a fuel pressure gauge in the external fuel pressure regulator so you can set your fuel pressure manually on the regulator. With these throttle body–based systems like the Holley Sniper setup you see here, the fuel pressure regulator is built into the unit and is pre-set from the factory, so why would you need a fuel pressure gauge? Right off the top of our
head, the quick answer is to verify fuel pressure from your fuel pump, but it can also be used as a diagnostic tool to show a weak pump, restricted filter, damaged/crushed fuel line, etc. Earl’s offers liquidfilled fuel gauges in both carbureted and EFI ranges (we grabbed the 0-100 EFI, PN 100187ERL) and this nifty AN -6 gauge adapter, PN AT100199ERL. Using the gauge adapter, we can easily install the pressure gauge inline between the supply line and the throttle body for initial startup and testing, and then remove it and store it in our toolbox for future projects or EFI system diagnostics.