Well to start off i have a 2000 jeep cherokee 4.0. my big question is why wont it run in the cold??? most of the time i have to prime the fuel system for it to start, but lately even after i prime it and crank on it, it wouldn't start. So aggrivated i kept trying to crank, after about the third time it'll start up, but its very weak. It'll idle at a little over 200 rpm and ill mash the throttle and it wont respond. i had a fuel pressure tester on it and it shows hardly any pressure. Which brings me to my other question i just changed my fuel pump thinking that would fix it. No such luck so i researched a bit and came to the conclusion that it was my regulator but it's new as well....please help!?!?!?!?!

 

how new is the regulator? still no pressure with the new fuel pump?

 

well the regulator was changed with the pump. and i just replaced the pump about a month and a half to two months ago.

 

Is the fuel filter plugged?

 

was it running right after new pump if so take pump back warranty it

 

What brand of fuel pump assembly did you install? I've had issues with Airtex brand fuel pumps.

If the pump is energizing and actually running, but you don't have fuel pressure at the rail, (need 49 psi plus or minus 5 psi) you have a faulty fuel pump.

 

i thought about that too and the thing is, this is the second time I've replaced the pump since December. I'm wondering if the problem is further into the fuel system?

 

Is it an Airtex? If it is, switch brands. Unless you have sludge on the bottom of your gas tank that is clogging up the fuel pump strainer filter, etc.....there really isn't anything left for a possibility.

 

its not an airtex, its a napa brand, but I'm not sure who manufactures them. you think it could just be sludge?

 

I believe that NAPA carries Airtex. I'd look at your receipt and find out the actual manufacturer of pump; it should be on there.

But it's a straight shot from the tank to the fuel rail, so the possibilities are limited as we have discussed.

 

yeah but the receipt just said napa fuel pump assembly nothin about the brand. so i think that its just a defective fuel pump...again