i've got a 2000 xj 4x4 with 4.0 in it. the dang thing will not start there is fuel getting to fuel rail. i tried turning it over and spraying some gas into intake and it cranked but then shut back off. any ideas what could be the problem.

thanks.

 

If you're certain you have fuel, the next thing to check for is spark. use a spark tester to make sure you are firing.

If you have fuel, and you have spark and it still won't run, it could be a host of issue. Anything from a bad crankshaft position sensor (a common failure), to a bad computer, to a short in the injector harness.

Be sure to check ALL fuses and relays, both in the cab and underhood.

Seriously though, if had been running fine one minute, and just suddenly stopped, and there are no blown fuses, relays, or other signs of shorting out, and you have fuel and spark, I'd seriously suspect the crankshaft position sensor. Do a search on here and you will find scores of threads about their sudden failure and the issue they will cause.

 

If it starts and runs for a few seconds with gas or starting fluid manually introduced, you have a "fuel delivery problem", not a spark problem.

And if the fuel pump runs for approximately 2 seconds with the key turned to the ON position (not start position), then I'd suspect that the fuel pump is failing.

Your engine needs approximately 49 psi of fuel pressure to start. It can easily be checked with a fuel pressure gauge installed on the schrader valve on the fuel rail.