Howdy, have a 87 formula 350, has a newer gm turbo syclone high volume fuel pump, 22lbs injectors and around 36 lbs fuel pressure, live were its hot, pump starts to howl after a few miles put on, repaced fuel lines by tank, see a trap or one way valve by rubber fuel lines under tank, when I hear it howl can smell gas, when the I take the gas cap off, lots of pressure coming out, is this normal? What is the purpose of that trap by fuel line? Thanks

 

This isnt the pump, its the pressure relief valve on the side of the tank. The cause is either lack of exhaust heat sheilds near the tank, or a CCP system that isnt working. If the CCP line becomes clogged, or the system otherwise stops functioning, pressure builds up in the tank to the point where teh pressure relief opens, and causes that noise you hear.

 

Thanks, I will look into it, forgot to mention that the engine check light comes on close to when this happens