no power to fuel pump..

[baddmove]

This is my post from the Bronco II forums at FTE

Thurs. morning i lost power to my FP, i thought it went bad so i spent most of my weekend replacing the FP..(it's in the tank) when i got done, still didn't work so i replaced the FP relay , still no power to the FP, what else can i try guys? I need my BII to go to work...maybe in the ignition?

o.k. i just put in a new ignition module and still no power to pump....

i am open to any suggestions.....

and yes, inertia switch is closed..that was the first thing i checked....

I checked the Main computer(PCM) by taking the one from the 89" out and putting it in my 86"...it worked just fine...getting cold here so i need to get this thing fixed as soon as possible

there are 3 relays in that box,the box under the big fuses on fender..(plug colors),grey,,orange and green..i checked the grey one...


Well..i took the whole panel to the parts store and it is showing 5 pins on the FP one, the other 2 only have 4 pins..so my FP one is the grey one...

I just checked and there is power the the green and orange one, but not the Grey one..is there a fusible link anywhere that you know of?

The 89" seems to have a lot of differences than the previous years..
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[doorgunner]

and the big fuses under the hood & little fuses under the dash are good????

sometimes I have to clean the contacts to the connector on the fuel pump relay...they get corroded...

check for voltage thru-out the fuel pump wiring circuit....somewhere something is damaged.....that's all i got...

 

[camshaft01]

ca chunck!

you could go hot rodder style with toggles and push button start. but you would end up rewiring everything that way. double check that inertia switch by changing it with a bone yard one. ive seen them go bad and would not reset, even though they click down. tech forums have the schematics, that might help too!

 

[Psychopete]

Do you have power past the inertia switch? Will have to use a test light or analog meter since the computer will prime the pump 2 times for 1-2 sec each.

Could also be computer relay. You got power with the key on Run at the red wire to the fuel pump relay? Do you have fused power (I think it's yellow or yellow/black) to the fuel pump relay? Be sure the computer is powering up, this is what ultimately controls whether or not the pump is on.

You can also ground a terminal at the diagnostic connector (some searching will show which one, think the tech library might have it shown under ECC-IV diagnostics) to supplement the computer grounding function. This would help narrow it down.

Just need to find where it's dropping off and work your way back. Intertia switch would be a good start to see if it's under the hood or further down stream FWIW.

 

[baddmove]

Well guys.. i got her going..i did a search around the battery area and found the main ground had pulled off..then i took off the rear wheel on the drivers side and reached in and disconnected the power to the pump, wiggled it around and hooked it back up and BAM...she started right up...so thanks for all the tips and posts...i'm just glad she is running again....
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