This issue is related to what was going on in my other post about fuel pressure etc.... but has developed into a whole NEW set of challenges... I apologize in advance for the length and detail, but maybe these posts will help someone else along the way as you guys have helped me...

So... the down and dirty.... 93 Ranger 4.0, swapped in manual, left auto harness, running rich, burping, no power, then would idle at 2500 RPM, surge and burp, fuel pressure at 40-ish then it would die. Pressure would hold for a bit and drop to 25 or so.
THEN... long crank to start would run for a second then die, repeat, repeat, repeat.... until... no fuel pressure at all. AND my code reader wouldn't work nor would jumping the grounds. (000 on reader and steady CEL)

Where I am now... No fuel pressure, pumps runs for 3 seconds and shuts off but will not build pressure when key is cycled repeated. Now the interesting part..... after watching YOUTUBE... i pulled the POSITIVE cable off and ran a test light between the cable and the terminal and got a light which I was told meant a short. Narrowed it down to the fuse #7 ( Instrument cluster, chime box, electric shift module). Removed fuse and turned the key on and heard the truck cycling through its tests and suddenly the CEL began flashing codes! 539, 629 and 566. 539 is b/c I left the vent in defrost ... How did it know that??? The other two are old codes from the auto trans.... torque converter and 3-4 shift module....
ANYWAY... still no fuel pump... I tested the relay.. its good. checked the inertia switch.. not tripped. got 6.8 volts at inertia switch and the pump UNTIL.... I jumped the two wires... it went to zero.. My way of thinking is that it should have stayed at 6.8???

if i put the fuel pump in a bucket of fuel, it pumps out fuel. I put it in the truck and it doesn't pump.... wired directly to 12 volts I hear it running but not pumping... If i had hair... I'd be tearing it out....

Is there a way to bypass the fuel system and go directly into the FPR to further isolate components? Of would there not be enough pressure though an external system?

As always.... thanks for any input and/or advice.... It is ALWAYS appreciated.

 

The FPR on the engine has the OUT, back to fuel tank, hose, the return hose

On the drivers side of fuel rail is the IN from the pump/filter hose

So did you maybe reverse these hoses?
If so thats the problem

Take off both hoses and put both into separate containers then cycle the key to see which one pumped out gas, that one goes on the drivers side of fuel rail
The other one goes on FPR


The voltage for fuel pump runs like this:

Battery---Fuse------FP Relay-------------inertia switch---------------------Fuel Pump--------ground

Computer closes FP relay by grounding it, and computer also has a FP Voltage monitor wire so it can tell if FP is getting 12v, this monitor wire is where the 5-8v comes from at inertia switch when key is ON, its just volts and no amps so no "power", so yes this voltage can just disappear if there is any "load" added to it besides a volt meter