93 ranger 4.0 crank no start

[Chasesauce47]

I was driving and my truck randomly lost power like it ran out of gas (I had half a tank), i went to crank it and it would run rough a few seconds then die on its own. I realized my fuel pump wasn’t priming. I’ve replaced my fuel pump, fuel filter, still not priming. Battery, alternator and starter are good, FP fuse and relay are good, what else can cause no power to fuel pump? At this point I’m thinking it’s a wire. Anything helps, thanks in advance!

 

[Brain75]

collision safety switch. Shuts off after a wreck so you don't pour fuel all over the accident scene. Passenger footwell has a big red button you reset. Tend to trip over big bumps, slight curb hits or even just die of old age.
You can check power on both sides to see if it is letting power through.

 

[Chasesauce47]

The inertia switch? It wasn’t tripped when I checked. Can I check the power on it with a multimeter?

 

[Brain75]

If I remember it right (no haynes with me), the inertia switch cuts off power not ground, the relay is supplied ground when the key is turned on (for 2 seconds)... so you should have power at both sides of the inertia switch with no drop in voltage (i.e. a good solid 12v)... any time you are probing around I always suggest 2 tests if you are testing a power lead 1) use the factory ground 2) use a "good" ground (stab the frame to get under the paint or touch a bare shiny screw head in metal etc etc...) what you are accomplishing with this is to see if the factory ground is still good.... if you get 12v from a ground location, but only like 8 or even 0 from a ground wire, then you have resistance/break in your ground loop somewhere.

 

[lil_Blue_Ford]

I’m moving this over to the 4.0 section

 

[Chasesauce47]

Update on crank no start:

I ran a temp wire to power on fuel pump, with a toggle switch and a fusible link. The fuel pump is priming now, but still crank no start. I don’t know what else to do at this point, does anyone have any recommendations? Thanks in advance

 

[Brain75]

Assuming you have one issue and not multiple, what would kill the fuel pump or wiring....
Hmm - any electrical fires, or signs of an electrical issue?

No chance you got a bit of water in the tank, or accidentally topped of with a couple bucks worth of diesel or or...

Some vindictive ex-girlfriend put sugar in the gas tank, etc?


Assuming you have multiple issues...
After getting the wiring to the point where the pump is pumping, standard troubleshooting... do you have good pressure at the rail (fuel filter backwards / clogged), does it catch and try with ether/starting fluid (indicative of a fuel or fuel system issue).

Do you have spark?

Possible you ran the battery too low trying to start it repeatedly.

 

[Chasesauce47]

No signs of fires, and my tank surprisingly looked Pristine when I put new pump in. New fuel filter on correct way, great fuel pressure on rail, and all my voltage is good. I have 2 battery’s reading over 12v when off and i ran the big 3 layout a few years ago (upgraded grounds with 0 gauge for a system) so I’ve got plenty of good voltage. It’s really hard to tell what’s going on when I’ve replaced 80% of the truck throughout the years

 

[Brain75]

well assuming you have the fuel delivery issue fixed and the fuel is good, check spark directly would be my next...

or a can of ether to verify no fuel issue at the very last mile depending on your tool collection and stock of misc sprays.

 

[DPDISXR4Ti]

Take a look at your EEC relay (can be jumpered for diagnostic purposes) and crack open the PCM itself to see if you have leaking capacitors.