I have a 1989 f150 302 5.0 liter. I replaced the rear tank with a new pump when I turn the truck on I can hear the both front and rear pumps working but it won't start. What should be my next step to find the problem?

 

do you have fuel/ fuel pressure at the engine?
did you replace fuel filter(s)? is a fuel line pinched/ not hooked up? Is the tank selector working correctly/ not plugged?

 

this thread may provide some clues, even though he has a larger engine. seems to be he had a problem with the tank switching mechanicals.

https://www.f150online.com/forums/pr...ml#post5201875

 

Will that selector valve some how prevent fuel from proceeding to the high pressure pump? I got one that will run fine on rear tank but when I switch to front tank it will die. New pump in tank. Or if the dash switch is shot and not sending power to front pump?

 

I'm honestly not sure, there are guys better versed on dual tank set-ups than I am on the forum. I never owned one or had a hand in fixing one so maybe if you post a new thread they will chime in?

 

The selector valve can be a issue that would cause it to not start. I had a truck that I could only run the front tank due to the selector valve not working. I would start by checking fuel pressure. Hook up the tester and turn the key one and see where it goes and watch to see if it drops without you trying to start it.