Loud Backfire and no start. Help requested.

[RhodeStiva]

Getting no where fast. checked relay good
checked fuel pump good
pulled fuel hose off filter and got gas in my mouth check.
got spark good
good battery
no start and loud back fire every once a while like it builds up a lot of pressure and then POWW

[tac]

The relay is controlled by Ignition switch when cranking and VAF when running could be a clue to the problem. The backfiring means intake valve is open when it gets spark. If timing to plugs is correct it sounds like a wiring/grounding issue.

[RhodeStiva]

Got it. Dizzy rotor. Thanks for all the info.