i posted in the bronco section and am not getting and replies. 86 bronco II, i have two pumps, a low pressure pump in tank and a high pressure on frame rail. i would like to know the purpose of two pumps. is the low pressure pump for startup, idle, low rpm and does the other pump take over when accelerating. i ask because my rig will not start and i trying to diagnose fuel pump problems. i have spark and all that but it doesnt seem that fuel is reaching the cylinders. plugs are dry and don't have any gas smell after i turn the engine over. i can hear the pump in the tank when i turn the key and i have fuel to the filter before it reaches the high pressure pump. i have had problems with the rig dying at low speeds and when stopped. it always started back up no problem. now overnight it wont start. thanks

 

My 92 Explorer, 94 Ranger, and a 90 Ranger that I've since sold, only had a pump in the tank. Is the pump on the frame rail an add-on? I've never seen your set-up...but I'm just a shade-tree guy. Are you carbuerated or fuel injected? There's probably a screen type filter on the pickup side of the pump in the tank. I've seen those plug up as well. Perhaps you could "tee" in a pressure gauge at strategic points along your fuel line, (before and after your filter and frame rail pump) and see if you have a pressure drop somewhere. Just rambling thoughts.....

 

That year had a low pressure pump in the tank and a high pressure pump on the frame rail. I would check and see if the inercia switch is triped. Have some one turn the key on and you should hear the pump in the tank run for 5 seconds the same for the one on the frame rail.On that model you allso have a relay mounted on the right inner fender under the hood. see if it clicks when you turn the key on.the relay may be green in color.Good luck