Jeep will not stay running

I just picked up a 91 XJ limited. When I try to start it, it will prime the injectors and fire, but after about 5 seconds, it will just die. It will do this as many times as I want it to, but it will never stay running. Any info you could give would be great. I checked the codes, and the only codes that come up are 12 and 55, which do not have anything to do with running, just that I disconnected the battery and that it is finished. Thanks
Brian

Won't Stay Running

HI LISTEN TO SEE IF THE FUEL PUMP IS TURNING ON CONTACTS HAVE A TENDENCY TO STICK. DALE [email protected]

I don't know if the 91 has this but my 90 does. It's a little white block about 2 inches long with a wire coming out of the face of it on each side. It's located on the driver's side fender wall near the air filter. I knocked one of those wires off when installing new shocks once and it did the same thing, start up and run for about 2 seconds then die as many times as I turned the key. I think it's called a ballast resistor. Your's could be bad or disconnected. I think you can bypass it (connect the two wires together) to see if it is that. From what I understand it steps the voltage down to the fuel pump after it starts. Otherwise it's a rather noisy pump and functions sufficiently at a lower voltage (probably extends the life of it too.) Let us know if you have that or not.

Try the fuel filter as well. Mine was having a similar problem, but check everything else that was recommended.

I had the same symptom with one of my '89s. There's a starter circuit that provides power to the fuel pump while the engine is cranking. One the ignition switch is released from the start position, a relay switches over to provide the power to the fuel pump via a different path. On the renix models, this is one of the relays under the plastic cover just aft of the battery. You can swap the relays around for trouble shooting purposes. You can also try bypassing the ballast resistor that was previously mentioned.

I will try the ballast resistor. I noticed that mine is cracked. I will try it tomorrow. Thanks guys. As for all of the other things, I know it is not them...the fuel pump primes, the filter is new, etc. Thanks again, and I will let you know if it is the ballast resistor.
Brian

jump a wire across the pins of the ballast resistor and then try it again, but I'd just about bet my life that the ballast resistor is your problem.

if it runs when jumped, then it's the resistor.