1987 ford E350 460 7.5L backfires

theoldwizard1 wrote:
First, with a fully charged battery, turn the key to ON. Your should hear the fuel pump (typically in the tank; listening at an open gas cap helps) for about 10 seconds. If not, you have a problem with the fuel pump or wiring including the inertia switch.

Second, the the key OFF and check if there is pressure in the fuel rail at the engine. There should be a Schrader valve (looks like a tire valve) on the fuel rail. Remove the cap and depress the inner button and you should get a good squirt of fuel. If not, you have a blockage in the fuel line, a problem with the pressure regulator, or the check valve is allowing fuel to leak back to the tank.

Third, after the engine has not been cranked for a couple of hours, start cranking it for about 20-30 seconds. If it does not start, stop cranking, press the accelerator pedal all the way down to the floor and start cranking again. After about 10 seconds and then start to slowly release the accelerator pedal. If the engine starts, you have a stuck idle speed control (IAC) valve. Sometimes these can be cleaned, but sometime they have to be replaced.