Fuel Pump

[JBronco]

Hey Guys, I got a 88 Bronco 5.8L and it will not start and i know why. When i turn they key before turning it all the way there is normally a buzz sound that i know is the external fuel pump charging the line. My truck does have the two pump set up with the one being in the tank and one mounted on the frame rail. I also know it is the one on the rail that makes that sound when you turn the key. Funny thing is that I tested the pump with a 9v battery and it still works. I have had this issue years ago and it was a computer relay (the little square one above the driver side wheel well) but when i blew that relay before when i took it off and shook it i could hear the little rattle from the burnt piece inside, when i take off the relay and shake it it doesn't rattle, I know that doesn't mean that it is good but before i get another relay i was just wondering one if there is a way to test those relays (the fuel pump and computer), and also if there is any other things that you guys could think of that would cause that pump to not come on when i turn they key. Thank you for the help.

 

[Rons beast]

Hey JB,

The relay gets power from a yellow wire and feeds a brown wire when it is closed. Then the power flows through the inertia switch. The inertia switch is located behind the drivers side kick pannel, or above the parking brake. It may be tripped. From the inertia switch a pink/ black wire feeds the fuel pump.

Reset the switch and if you still have no volts out of the inertia switch, start checking for power in. Then check for power in to the relay at the yellow wire, and out at the brown. This of course with the key in the run position

If you have power in at yellow and nothing out at brown, check if you have power at the red wire on the relay and ground at the tan/lt green wire. If all that is ok, then the relay is bad.

Good Luck

 

[miesk5]

yo This may help as RON advised;

Wiring Diagram in an 89 5.0, 5.8 & 7.5 from Ignition Switch & Fuse Link N through EEC Power Relay; miesk5 Note; G801 is located on the LH inner fender behind the headlamp & both pumps Grounds join @ Splices S155 & S903

http://broncozone.com/topic/20547-fuel-pump-wont-shut-off

by Seabronc (Rosie, Fred W) at Ford Bronco Zone Forums

and Wiring Diagrams in 89 (INCLUDES BRONCO & Single Tank F 150); 91 (INCLUDES BRONCO & Single Tank & Dual Tanks & Pumps F 150) & 95 F 150 w/Dual Tanks & Pumps

Source: by Ryan M (Fireguy50) at http://oldfuelinjection.com/?p=36