powderpainter

I have replaced the fuel pump,the crankshaft position sensor ,and tested all the relays

the car turns over and you can tell it wants to run but I cant get the fuel pump to run its brand new and I replaced the cps as well and tested all the relays

but still nothing and I cant get it figured out

BuckB91XJ

Did you hook your + and - wires up backwards on the new pump? Trust me, it can be done and if you're not positive they are right, you probably did. What this does is make your pump run allright, making noise, making you think it's fine but, it's actually running backward trying to pump fuel out of the fuel line into the tank.

powderpainter

the harness only plugs in 1 way , and yes its hooked up the right way and you can only hookup the harness 1 way

I know that when you hook them up backwards it will run backwards thus sucking and not pushing (same as a fan)

the pump will run when you jump it with a 12v but not unless I jump it
I have power to my harness (fuel gauge still works )

relays are good f,uel pump is new, and crankshaft position sensor is new,
but when I turn the key the pump dont run

OverlandZJ

read this thread and try the process stated within.

It costs nothing and will tell you if it's the computer... which it very well could be.

https://www.cherokeeforum.com/showth...light=computer

powderpainter

thanks for the link ,
but its not the computer everything on the car works perfect ,just the fuel pump doesnt run when you turn the key

you hear all the relays clicking just as they should I have power to the pump harness but its like something is telling it not to send fuel or something,
my wife was driving the car and anytime I have ever had a fuel pump go its when you shut it down not running(but since you could not hear it run when you turned the key I replaced it) and then when it didnt solve it I was told the crankshaft sensor

I asked my wife what it did when it died and she said the pedal went to the floor and it died and I asked again in different form and she says the last thing it did was die LOL so you see what Im workin with

OverlandZJ

I was in the same boat, couldnt figure it out. I went searching on ZJ specific boards and found a few threads that lead to this, which fixed my wifes rig.

Humor me and try the process.. doesnt cost a dime or hurt in any way.. promise. If it doesnt work, you ruled it out.

http://www.jeepsunlimited.com/forums...d.php?t=418265

powderpainter

I never understood the point of posting a link ,

you say what fixed your wifes rigs problem

if there is a part of either of those links I should be focusing in on that may help but otherwise I see the same links on google

but like I said its not the computer

oh and I forgot to ad its a 4.0

I read what you said about turning the ket etc but even when I turn the key the pump doesnt prime the rail the pump dont do squat unless I give it strait power and then it starts right up

OverlandZJ

Then i cant be of help. Good luck...

Your edit.. the reason the pump runs is because your bypassing the relay correct? The computer controls the relay..

powderpainter

its on the passengers side engine compartment infront of the glove box

but from everything I have read my computer is fine and that in the 97 there is like 5 things that control the fuel delivery

and do appreiciate your time and help on this

and you can hear all the relays working and they were tested on an ohm meter and were fine

ol"blue

Have you checked the ASD relay and fuse, and the fuel pump fuse in the PDC? I saw you stated you "tested all relays", but I'm just trying see if you've missed something.

powderpainter

there is no fuel pump fuse that I could find

only the relay which is right next to the ASD relay

ol"blue

In the Power Distribution Center under the hood, there is a fuse F6 that powers the fuel pump relay in the PDC. The ASD relay gets power from fuse F2 in the PDC. I can't scan this diagram but in the PDC also check fuses F15 and F3, and the fuel pump relay and the ASD relay. All this is in the PDC under the hood. Hope this helps.

powderpainter

all of the little and big fuses are fine they were the 1st ones I checked
and then in the inside theres another fuse box that has absolutly nothing to do with the engine and those are all fine as well

thats what leaves me at a loss is that none of the fuses are blown
and I tested all 7 relays and they all tested out fine on the bench

powderpainter

so I am the only person this has happened to

hypodiesel06

Hello, this is my first time on here. i joined cause i have the same problem. no fuel. I have a 1996 xj with the 4.0L. i am only getting 4.6 volts to the pump. Im going to start tracing today. Will let you know.