Odd Fuel delivery issue bad pcm or pump? clicking relays now nothing

[challlen]

This problem was stumping me, then it got weirder. So it ran perfectly fine earlier in the day. Toward nighttime I turn the key on and the normal priming of the pump for maybe 2 sec happened. It then kept repeating itself clicking the relay and flashing check engine light in unison. I swapped relays around, didn't help, checked inertia switch(didn't jump it), tried disconnecting battery, checked fuel pressure on rail, fuses. I could hear the pump priming and i guess returning the fuel cause you could hear a lot of flow the truck not running and fuel pump going crazy.. Now after a lot of checking fuses and switches and relays it happened at one point where the pump would not even cycle with key on, like the relay didn't wanna work or something similar.. I kept trying to get it to kick back on, switching relays and turning the ignition, it soon started priming again like before. Now its changed, at this point I cannot get a click from the fuel pump relay, no pump action/noise, and no start.. before when it was constantly priming/clicking i could get it to idle just barely. this is all over a course of 9pm-midnight i kept doing more research and I've gotten to this point. What should i check now i don't wanna just put a new pump in it to just to have clicking relays again. Ive heard ecm/pcm they go out. I'm going to junkyard tomorrow to get a pcm. I really hope its just that...

 

[challlen]

i feel like this could be the ecm/pcm basically frying itself. maybe it needs a pump too. LOL smh I've read elsewhere people have inspected and found burn marks and failed circuitry on the board and replacing magically fixes their problem.

 

[Macgiobuin]

1. jump the relay so that there is power going to the pump. -No running pump? Pump or pump circuit is bad. Running pump? Possibly bad PCM.
2. go to the connector that carries the +12v and ground connection to the pump; it also carries the level sender signal; disconnect; jump the +12v and ground. -no running pump?
3. Take down the tank and try jumping the pump while the assembly is out. I have found may times the ground wire or connector from the pump through the plug can go bad. Splice and solder the bad wire segment. Test pump with direct +12 v. Should be good then.

 

[challlen]

battery-fuse-relay-inertia switch-pump

1. jump the relay so that there is power going to the pump. -No running pump? Pump or pump circuit is bad. Running pump? Possibly bad PCM.
2. go to the connector that carries the +12v and ground connection to the pump; it also carries the level sender signal; disconnect; jump the +12v and ground. -no running pump?
3. Take down the tank and try jumping the pump while the assembly is out. I have found may times the ground wire or connector from the pump through the plug can go bad. Splice and solder the bad wire segment. Test pump with direct +12 v. Should be good then.

went back to the original problem after messing with relays, i think one was slightly unplugged. going to replace 2 even though they all click/work. so it sounds like pump/relays and possibly injectors cycling over and over every 2-3 seconds when i turn ignition to ON. check engine light flashes with the clicks

 

[Macgiobuin]

Sounds like it may be an electrical load problem. If your starter motor turns over, then the problem may be where the battery cable connects to the fuse/relay box under the hood. Try this: take out the relay that runs the fuel pump. Do the start-up routine again, but a half second after you turn the key to 'on' (don't try to start), turn on the heater fan 100%, then the headlights. If that triggers the check engine light dancing (not enough voltage to safisfy the PCM), disconnect the battery and look for corrosion at the positive bus where the battery cable connects. The starter circuit may be unaffected, while the rest of the car is.