Fuel pump issue?

[Cre8tive]

anyone possibly no were I can start with this I’m completely lost and have done all the basic checks I could find online?? 

 

here's my situation i replaced my fuel pump about 2 months ago, It started just fine at the time, i ran for about 40 mins then left alone (trucks been sitting since in the garage)

 

Threw out the 2 months, I’ve been turning on my truck and letting it idle for a while and one day out of nowhere the pump decide it would only sometimes turn on and prime and after a couple day of that going on it decided to go further and just stop working and now thats basically we’re I'm at with it and also when the pump started acting up I stopped running it to not cause any damage 

 

Ive checked the fuses/relay also swap them around, Ive ran a wire from top port to bottom port on the relay and check to see if power is reaching it.. there was at (12v+) all my grounds are original but I’ve sanded my truck down to bare bone and painted it so there all pretty clean, and I’ve checked and ran a hard line to that clay thing for the pump and to the pump itself threw the harness and that did nothing?? Also tested the foward plug to my tank that’s part of the main harness and when I turn my key on it jumps to 12v+ then to 0v 

 

I'm kinda lost wouldn’t mind your tips, links or anything ideas u guys might have?? Did I put my pump in wrong? Is it shorting out somewhere or are my grounds needing upgrading, do I need a new sending unit??? Anything at this point is considered help

[Dzimm]

Double check the ground behind your driver's side taillight, it's an extremely important ground point.  Also do the Cruiser's tips relating to upgrading grounds.  Since you say the 12v comes and goes right away, it sounds like the computer might be cutting fuel.  Try running 12v directly to the pump under the truck and see if it kicks on.  If it does, then you know the pump is good so you can start checking sensors. 

[Pete M]

I added a new ground to the harness right by the pump.  12 volts doesn't mean it can also push the amps through.  

 

but also the current crop of chinese fuel pumps can't be trusted so you may need to pull it out for a closer inspection.     

[Cre8tive]

Thanks for the helps guys 👍 so this I we’re I'm at now, I’ve checked my back ground behind my tail light again to be safe and it looks good also I just tried running strait power to my pump and nothing happened no prime sounds or whispers of any sort?? 

 

Does this mean my pumps gone bad again? 

 

[Pete M]

run power and ground to it.  if the ground is insufficient, the 12 volts has no where to go.   

 

oh, and corrosion can creep into the rear harness connector right behind the rear tire.  if the ground wire connection inside there is kaput, the pump can't ground. 

[Cre8tive]

Hey so I figured out what was wrong, thought I’d let you guy know what it was

 

I guess my computer was burnt out and sending power threw my fuel pump ground and burning them out but at last with only 4 fuel pump gone I have her running and in 5 year she’s tasted her first chunck of gravel road it was pretty nice for only 2.5l little 2wd (for now) 

[Tommot_1]

I am modify Cherokee Pumps  to fit the Comanche here’s a picture of bow one that I modified and the stock one kaw4sale@yahoo.com