My friend bought and 86 bronco with a FI 302. The fuel pump in the tank (low pressure pump) went out and so I replaced it for him. Now the pumps won't kick in when the key is on. I already checked the shutoff switch on the firewall and it's fine. If I jump the eec-iv under the hood (they have a fuel pump tester on them) then the pumps work fine and I can start the vehicle. I have also pulled the relay on the d/s firewall by the brake booster and it also works when I jump that. I tried a different relay out of a wrecked truck, but it still doesn't work. Anyone have any ideas (other than I got a bad relay)??? It's starting to drive me crazy. Thanks for any help.
Justin

 

Check the inertia switch. It should have a red reset button on it. Bronco894x4

 

When you say jump the relay are you putting power across or are you grounding the relay like the pcm is supposed to do. The relay should have 4 circiuts. pcm ground for control, key power to turn it on when the pcm grounds, output to the pump (may go through the inertia switch, some models the inertia switch in on the keypower side), and fuel pump vpwr from the fuse panel. (thats all off the top of my head but gives you an idea how the relay works.)

 

when I jump the EEC-IV I ground it off, and when I jump the relay, it's the power that runs into the relay (so it shuts off with the key). I just pulled the relay out and ran a wire across the 2 contacts in the plug.

 

Have you done anything with the battery or battery cables? I had this very same problem after I rebuilt my motor and replaced the battery cables. I forgot during the process about a ground connection that came off of the battery it was the direct ground to the computer. Look to see if it is still plugged in there is a single wire that goes into a single connector. I could not get the pumps to come on or anything. I would jump the relay and hear the pumps come on but, still nothing did not try jumping EEC-IV. Hope this helps and Good Luck,

Rick
86 302 EFI, bored 60 over, AOD,
Headman Headers, Flowmaster 40 series,
2 inch dual exhaust, MSD ignition

 

 

Sorry-went to montana for the weekend so couldn't write back sooner. The wire is fine. he had problems with it before-put a big battery in, went offroading and broke the wire. Happened at nite, and I had to tow him home and fix it the next morning. So I know it's not that. Anyone else have any suggestions? Thanks for the help so far.