So I've asked this before and didn't get an answer as to what part I should replace ive mostly gotten things to troubleshoot which I already have and the truck fixed itself last time but it's back to not priming so I've been using ether and it starts right up with a check engine light that clears after a bit and runs better but today it just keeps running rough and doesn't start without help every time, I've already replaced a bunch if you're wondering (new expencive sending unit, new gaskets and lock ring sealed the tightest it's ever been, new plugs, new ecu replaced for a different issue but seemed to solve the priming problem temporarily, new fuel filter, with a fully charged battery) I've read a bunch of forums and watched videos with people having the same problem and it seems to all come down to the fuel pressure regulator which I finally found on mine so I'm ordering one tonight but I wanted someone to change my mind before wasting more money on something that might not fix it. it's a 1993 4.0L OHV and yes I already checked the connectors in the fuse box and used a jumper wire and hotwired 12v to the pump and it'll run the pump it just won't start or prime on its own turning the key it just keeps running and I can hear gas flowing in the engine bay (no leaks just a water running noise) there's plenty of gas at the Schrader valve but I doubt it has any kind of pressure (it will still run off that just rich like I said)

Also I took the vacuum line off the pressure regulator and there wasn't any moisture or gas in the line which I heard was the way to tell if its bad or not so that's why I'm questioning replacing it but I've also heard it's fixed others with the same issue same truck

 

1993 4.0l, you buried the lead, lol

You think its running Rich because Smoke comes out the tail pipe?

Lets see
Crank engine over a few times with a No Start
Pull out 1 or 2 spark plugs
They should be WET with fuel, if so light the tips with a match, should burn fast and bright, if not then its not gasoline, period, something else is coming from the gas tank but it ain't "fuel"
Siphon gas out of the tank as best you can, add fresh gas with 10% ethanol mix

If spark plugs are WET and tips burn well then check the gap on the spark plugs, 4.0l OHV uses a wide gap, 0.054"

If spark plugs are DRY then no injectors or no fuel pressure
1993 is OBD1 so there will be an OBD1 connector in the engine bay, should be next to the engine bay fuse box, firewall end and may still be attached to it with cover that says EEC, remove it so you have access to the slots
Connector looks like this: https://www.therangerstation.com/tec...v_testing2.gif

Fuel Pump slot is label in the diagram, that slot is the GROUND for fuel pump relay, its connected to computer pin 22 and the Fuel pump relays ground
If you put a jumper wire in that slot and then to a Ground, like battery negative, then when you turn on the key the Fuel pump should come on full time
Do it
You should now hear the fuel pump running in the tank, only with Key On, its not quiet, and no this does NOT hurt a thing, fuel pump runs full time after engine starts

While fuel pump is running see if engine starts if so then could be your Fuel Pressure Regulator(FPR) is bad
FPR is just a spring valve, spring holds the valve closed until pressure is about 43psi, then its pushed open and lets fuel flow back to the gas tank, so the fuel hose on the FPR is a RETURN hose, not the IN from filter
If the spring should fail then fuel just runs out and back to the tank, so 0psi pressure for start up
Once engine is started, with ether, then fuel pump comes on full time and there should be 5 to 15psi at the injectors, fuel pump can generate 70+psi which is why system doesn't stay at 0psi with engine/pump running, FPR is still a valve so does slow the exit of fuel back to the tank

There is a fuel pressure test port on the engine
With pump on and engine off you should see just over 40psi, if not FPR is most likely bad
With engine running 30-40psi is what you will see

The vacuum line on the FPR lowers the pressure a bit and it will have gasoline in it only if FPR is leaking, it doesn't always leak when it fails

 

I'll do all that tomorrow and the FPR should be in soon, from the sounds of it should be bad lol. yes it runs rich rolling coal out the tailpipe and smelling unburnt gas and it falls on its face for half a second before revving, it's very late so I'll have to read the other subjects you talked about but thank you