Fuel pump delivery module probing giving unusual results
ALL THIS IS CART BEFORE HORSE STUFF.!
1- fuses are first blown
2: scan the PCm is next ,after all if PCM detects spark dead it cuts fuel dead in blink if an eye,(as in no crash and burn as seen on TV)
3: if above is not helping (no DTCS) the we,,
we check fuel pressure on the rail, cranking or at idle.
if out of spec we check FPR and the PUMP voltage.
if pump is dead, 0 PSI (bar) we check voltage to the pump actual
12vdc good or 0v bad, below 11volts bad or battery is weak.!
that is how all EFI is tested,not guessing, not discovering pins the PCM that
floats (ever hear of tri-state logic)
the output of a pcm or computer or any logic module can be
1; 0V GROUND DRIVEN STATE
2: 12v or 5vdc drivenstate
3: or floating, as in not used now and floats to save energy.
best is work from a service manual and no guess and the real schematic.
what matters is,
1: NO DTCs for spark dead, (p0300 is weak spark not dead)
2: pump pressure at spec, cranking and at idle of can be sustained.
3: if pressure fails cranked (a 2 man test) and 12vdc is on the 2 pins of pump cranked then the pump /FPR is bad.
if voltage is wrong at the pump we work backwards to the point of failure on those 2 wires, pump feed.
that how this is done, and not taking a bath in fuel tank dropped on a whim.