no fire to fuel pump

I'm new to this site, and I've just bought my son an 93 xj.. We've had cj's all our life but ran across this one that somebody had invested in pretty heavy, let it sit and then sold it.. it wouldn't fire when we went to pick it up but if you give it a drink of gas it runs for a bit and dies.. tried the fuel pump relay.. it's good, also the plug in the relay box is hot on 2 sides with the key on.. tried to jump it acoss the insulator but still the pump wouldn't engage.. checked both sides of the wires that plug to the insulator and they are cold.. no pressure on the fuel rails obiously.. because i can't get fire from the relay to the green wires on the insulator.. The colum has been messed with and a starter button wired in.. but still with the key in the on position we get fire to the relay.. I don't have tons of time right now to think this through and was hoping one of you xj guru's may have some other quick checks for me to run.. ( old man ?? ) His write up was where I started..

Thanks in advance guys..

No words of wisdom ??

check for spark too! i bad cps will knock out the fuel pump and spark, via the asd relay. when the pcm is turned on via the key it will check sensors. if the cps comes up as a dud it will not procede forward to energize the asd relay which in turn energizes the fuel pump relay! if you do not have spark you found ur problem. if you do have spark it is most likley another problem! mike

your "ghetto" column sounds like a trip!

run a hot wire to the pump to see if it kicks on. If it does track your wiring and see where the problem is.

x99j said:

check for spark too! i bad cps will knock out the fuel pump and spark, via the asd relay. when the pcm is turned on via the key it will check sensors. if the cps comes up as a dud it will not procede forward to energize the asd relay which in turn energizes the fuel pump relay! if you do not have spark you found ur problem. if you do have spark it is most likley another problem! mike

your "ghetto" column sounds like a trip!

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But he said that when he gives it some gas it starts? Doesn't sound like a CPS problem to me at all.

The best thing you can do is jimmy rig up a direct hot and ground path to the fuel pump, but make sure you know which wire is which.

Yup.. I thought of that too.. I actually checked the wiring ( all of them ) that runs to the fuel tank with a test light and got nothing, checked the wires at the insulator on the lt inner fender and got nothing there either.. Wondering if there is another fues or relay somewhere else that controlls the fuel system ? or works wit/or interferes with it ?

mattbred said:

But he said that when he gives it some gas it starts? Doesn't sound like a CPS problem to me at all.

The best thing you can do is jimmy rig up a direct hot and ground path to the fuel pump, but make sure you know which wire is which.

Click to expand...

my bad,:dunce: i had a senoir moment!

I think there is a ceramic resistor under the hood somewhere that controls the fuel pump, but I'm not sure where.

Jess said:

I think there is a ceramic resistor under the hood somewhere that controls the fuel pump, but I'm not sure where.

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The ballast resistor on my 92 was on the drivers side inner fender. It is white ceramic about 2" long, you can by-pass it. JIM.

Yup,
Tried that.. No fire at either contact either wire..
Not getting fire from relay to the insulator wires....

You have two fuel pump relays, find the other one, it's called the bypass relay.

I think it's located on the firewall near the blower motor.

so bypass relay.. have a photo of it maybe ?