Fuel pump

[shadow88]

A few weeks ago my b2 started missing when I would go up hills or have to give it a lot of gas, then the other day it wouldn't start, it sat a day then fired right up! Drove it all that day and then the next day it wouldn't start! Put a fuel pressure gauge on it and was getting only 10psi with key on, then no pressure, so I changed the fuel pump, still no pressure, I had a couple fuel pump relays from my two donor trucks and tried them and still no luck, I did do a search on here but didn't get very far, thanks for any input

 

[LIMA BEAN]

Check you fuel pressure regulator.
Edit: not sure if a 4.0 has a reg like 2.3 and 2.9 so the 4.0 crowd will hae to chime in.

 

[basketranger]

I would go to the fuel pump cutoff (the one that trips when in an accident - supposedly), they do get weak, not sure about bII but passenger floor board in behind carpet under hvac box. remove harness plug and insert a 5 amp mini fuse. if problem goes away replace cutoff if not Happy Hunting. just for giggles did you try a fuel filter.

 

[shadow88]

Changed fuel filter also, did swap out that switch with one from the donor I had

 

[shadow88]

So I ran the codes and this is what I got, 57 Intermittent in Park/Neutral/ Switch or Neutral Pressure switch circuit - PNP or Transmissions, is this saying my neutral safety switch is bad? It turns over but I can't here pump kick in and I still have no pressure, again input is greatfull, I need to get this thing back on the road!!

 

[shadow88]

Scratch that, #57 in my book says octane adjust service pin in use/circuit grounded??

 

[broncobuckinaround]

shadow which pump did you change. there are two. rear is only 6psi and the front is like 99psi from what ive heard and read. or it can get as high. idk.

 

[shadow88]

Mine only has the pump in the tank

 

[PanamaExpat]

I was having some strange no start issues with my 94. It would start and run then it would die and not restart. This happened right after I reinstalled my carpeting. The fuel pump was not turning on all the time. Checked the inertia switch and the button was down. Tried different relays, checked fuses, etc. I needed to lift the bed again to aid in installing a new rear bumper so I checked and no 12 volts to the pump. Had voltage at the inertia switch. Smacked the inertia switch with a screwdriver handle. They make some funny noises when you do that. So I smacked it a couple more times just for good measure. Pushed the button back down and now she starts and runs just fine.

I know you said you replaced it... Try jumpering the inertia switch plug and see if she starts up. That inertia switch could be oxidized inside and not making good contact. Another old one could have the same issue. Take it out, shake it real good, trip it a few times, and then throw an ohm meter on it to see if it has near zero ohms and good continuity.

 

[country0001]

I had similar problems with mine and had some bad contact points on my fuel relay.

My donor was a 94 ranger, but I took everything. Check your relays and swap them around

 

[shadow88]

After chasing wires checking for power to the pump, I found a spot where the wires go over a cross member, the power wire to the pump was cut about half way through, spliced and soder and everything works!! Next time I'll chase wires before I just assume its the pump, but the pump was 20 some years old so I'm not that disappointed!

 

[broncobuckinaround]

thats strange. but you should have two pumps.

 

[country0001]

thats strange. but you should have two pumps.

Gen 2 B2's went to a single pump in 89.

 

[broncobuckinaround]

lmao lucky them. lol. but ill remember that one.