Working on early Ford (1985) multi-port fuel injection system. Not running engine, testing fuel pressure OK at 40psi. After test, noticed a very quiet ticking sound (never started cold engine). Listening closey, the sound was two part, first a ping, then followed in about 1 second by a tok, ..... ping - tok......ping - tok........and this repeated for about 2 minutes until the fuel pressure guage dropped to 20psi where the sound stopped and pressure stabilized.
At first I thought it was the fuel pressure regulator, but now I'm thinking it is a defective injector.
Is it possible for a bad injector to pop open on its own under pressure?
-Pete, in Tacoma WA USA