I'll apologise in advance if I sound like a newby ( I am!)

I'm in the process of replacing the injectors on my 350 TPI (just waiting for them to arrive). I'd like to know:

Where/how is the best way to release the fuel pressure before removing the fuel rail?

Where/how is the best way to measure the fuel pressure and what should it be? (A previous owner fitted an adjustable pressure regulator, so I want to make surer everything is set up correctly)

The injectors that I have ordered are 22lb.

Hope that's enough info!

 

There is a shrader valve on the rail for checking pressure. You will need the correct adaptor and a fuel injection pressure gauge.

The regulated pressure is 43.5 psi with the vacuum line disconnected. Typically will drop about 10 psi (20 inhg) with vacuum line connected at idle.

Depending on what injectors you ordered, and if you are going to tune or not, you may want to use that pressure regulator to dial in your BLM's if the injectors flow slightly more or less than the originals. Or you can set the pressure to 43.5 and change the flow rate scalar in the tune.

GD

 

Welcome to TGO!

The fuel system shouldn't stay pressurized very long. I don't wanna throw out a time, but if you leave it over night without turning on the ignition, it should be very minimal. What I normally is to have a towel or rag ready, and loosen one of the fitting over by the frame rail, not on top of the engine by the rail. It's just messier. Get it loose enough to turn by hand.....it'll start to drip, and then wrap the line in the towel and finish unscrewing by hand, letting the overflow soak into the towel.

As for proper fuel pressure, you want about 42.5 psi, at idle, with the vacuum line going to the regulator DISCONNECTED. This simulates the vacuum condition you'd see when at wide open throttle, and that's where you want max pressure. Plug the regulator vacuum line back in and you'll probably see mid to low 30's, but that's not what you're testing. You test for WOT.