peptech1

does anyone have any idea why my fuel pump will not get power...i have a 86 bronco 5.0 it has the frame mounted high presssure fuel pump got in the other day started it ran about 3 seconds and died and wont start .found i wasnt getting fuel pressure ..checked power to fuel pump and nothing replaced relay still nothing ...relay has 4 wires 1 is always hot another gets power when key is run position ..a 3rd wire will give power to the pump if i jump it .it activates the relay theres no signal going to this wire and that is the problem.does anyone know what sends the signal to this wire on the relay ?...also if i ground that same wire it activates the relay ...does that mean there is a short somewhere?...any help would be great ..i already checked the saftey inertia switch and thats not it ...thanks carter

roofi

The ECU fires up your fuel pump (via the relay) for a few seconds when you turn the key on. If there is no engine cranking detected, the ECU shuts the pump off again. This is by design.

You may have fried your ECU by applying power "in reverse" to the relay, or it may have already been fried. Alternatively you have an ignition problem (no pulses) which is why the ECU is shutting down the fuel pump.

__________________
XF PV EEC-IV
Subaru RX Turbo
Van Diemen RF86
Softride Powerwing