How to diagnose Fuel pump issue

[Colad]

Hello all.

I am looking for some help. I have a 91 Bronco with a 351. I had an issue with a weak battery and bought a brand new full size die hard Gold. I started the truck and she started running for about 15 seconds and then Died and will not start again. I cannot hear the fuel pump prime when I turn the key anymore. I would like to avoid changing the Fuel pump if I don't have to due to the work and expense naturally. So I am wondering how/where to start trouble shooting? how do I check the relays/inertia valve? I have a computer checker and will read the codes, what should I be looking for. any help is appreciated!

 

[Justshootme84]

Welcome to Bronco Zone!!! Your 91 actually has 2 fuel pumps, one inside the gas tank and one along the driver's side frame rail, under the door. You also have a pressure regualtor, filter, and relays. If you have a Haynes or Chilton repair manual, it will help you to diagnose most problems. You can also go to the HOw-To & Tech articles forum. I have links to a couple of websites with info on Broncos, like Miesk5 HomePage or the Univ. of Maryland. These will help with deciphering trouble codes, and checking voltage to the pumps and relays. IF your fuel pump inside the gas tank went out, it is a real bear to drop the tank. That fuel pump and sending unit are in one assembly. JSM84

 

[89Bronco58]

not being smart, but r u sure u have gas in the tank, it is possible the sender could be bad and saying you have gas when u really dont, i only say this because my fuel pump in the tank was totally taken out and it still ran off the fram rail pump, if you do have gas id forst start by getting your head right under the tank and having someone turn the key on and making sure it isnt kicking on, and if it snot, you may need to replace it

 

[swampthing]

change fuel pump relays..round 15 a piece depending ont he store..should cure the problem...try running a jumper wire from the battery down to the pump see if it turns on but my bet is on the relays

 

[firelt90bronco]

Why not check the inertia switch located on the drivers side under the dash. Maybe it went off by accident.

 

[Colad]

Thank you all for the suggestions, I will be working on the truck on friday, got the whole day set aside from it and I wll start with these! thanks again!

 

[MasterBiss]

i also had a problem with my fuel pump relay, but it was stuck "always on" which was killing my battery. I'd start simple with checking the relay. good luck!

 

[firelt90bronco]

In replaced my fuel pump last week, all the relays and the igniton module and it still won't work.