93 XJ crank but no start
Hi folks, I've been having a hell of a time getting to the source of this issue.
My Jeep died on me, just shut down while driving and wouldn't restart. found a badly cracked 90 degree elbow on the fuel pressure regulator and wet with gas on the back side of the regulator. Got pulled home and after a while it started up fine and ran for a few minutes before the engine killed again, but wouldn't restart till it sat for about a half hour or so, and would only idle for about a minute and die. I replaced the fuel pressure regulator and rubber elbow, but no change.
Got a friend with a pressure regulator over here and was able to test pressure on one of the occasions that it started. idle pressure was around 30, but right after it died pressure would drop off fast (within a minute). Eventually, it got to the point where it would crank, but not start even after sitting for hours.
I replaced the ignition coil, cause I've had issues with that a couple times and it's cheap. replaced the CPS a couple years ago with an $80 OEM CPS which turned out to be a coil problem, so I put the old CPS back in. New cap and rotor, still crank and no start, but now it was sounding like it just wasn't getting gas so I put the pedal to the floor and it finally started. I kept my foot lightly on the gas for a while and it kept running. let off the gas and it idled without stalling. let it run for about 10 minutes and everything was fine. Drove it to the store and back (about a 10 mile round trip) and no problem. shut it off and it started up right away.
I was thinking it might be the fuel pump. I can hear it run for a couple seconds when I turn the key, but the fast pressure drop suggested a bad check valve in the pump anyway. Drove it the next day to the auto parts store and used their pressure gauge. #30 at idle and quick drop off on shutdown. got a new fuel pump and drove home. checked codes and had 51. changed fuel pump after a hell of a time getting the old lock ring off. With the new pump installed I got crank, but no start. Pulled the hose off the input to the fuel pump and it was dry as a bone. I could hear the new pump running like it should with the key turned, but it wasn't pumping. I put the old pump in and it started fine.
This is currently my only vehicle and so while it was running I had to go get some thing done. It's been about a week now and I've driven it over 600 miles with no issue, and the 51 code is no longer there, but a couple days ago on my way to the gas station I discovered fuel spraying out the side of the fuel pressure regulator seal. Took it off when I got home and found that the O-ring was nearly sliced in half. I put the O-ring from the old regulator on, but now I'm back to the crank, but no start problem. It fired a couple times, but never got it running. Got a new fuel pump, fuel filter, and battery. This time the new pump is getting fuel to the filter at least, but still no start. I don't know where to look at this point.
Here's everything I replaced since this all started:
cap and rotor
fuel pressure regulator
cleaned IAC and throttle body
switched CPS with older CPS
I'm done throwing money at it till I can narrow down a cause.
I ordered a spark tester, fuel pressure gauge, and compression tester which should be here tomorrow, but every day this things not running I'm losing money by not getting to my jobs.
Any Ideas where to look next?