First off i'd like to say thank you to all the great tips and advice on this forum. I've followed ALOT of advice on this site before becoming a member. so THANK YOU!
Now my issue... I've got a 92' YJ 4.0 I6. It died on me on the freeway (little to no throttle response followed by very rough idle, then ultimately nothing). after getting it towed home, I jumped on this site. I started shotgunning parts at it... My list so far includes: Fuel Pump, Fuel filter, new fuel lines (they were old and brittle), Fuel pressure regulator, Throttle positioning sensor, Crankshaft sensor, cap and rotor, plugs and plug wires. I'm at a loss now. i've replaced almost everything that all the trouble shooting posts on this forum have reccomended and still have the problem.
It will fire up, idle for about 5-10 seconds and then die or it dies sooner if the throttle is pressed.
The battery is strong (Optima Red Top less then 2 yrs old), i've triple checked all my vacuum lines, my ground is good and clean connections. I have a good buzzer and my Check Engine light and such come on when i turn on the key. I hear the fuel pump prime and when i replaced the fuel pressure regulator i turned it on and had good fuel come out the hose while it was disconnected. I also have fuel coming out the test port on the rail until it depressurizes.
Sorry for the novel here but i wanted to provide as much detail as possible for any readers. Any and all advice is welcome!
no... it will turn over once after its been sitting for about 10+ minutes then die quickly (5 seconds or less) or as soon as i touch the throttle. it does that warm or cold ( i live in southern arizona) so its not really COLD. as far as codes, all i'm getting is the normal 12, and 33. i've gone thru 2 fuel pumps (1 was about 1/2 the normal psi) but this latest one is reading good. fuel filters facing the right direction, no kinks or pinches in the fuel line. it will start and run with starting fluid and will continue to run as long as i keep hosing her with juice. so its gotta be a fuel issue... but i'm at a loss as to how or what.
I know you said that there were no pinches in the fuel lines... But double check the return line, specifically, where the pass over the rear crossmember, after the filter, right before the fuel tank. That return line can easily be pinched between crossmember and tub.
Apollo12227 has a good point. If it starts and runs you have spark, compression and at least some fuel. It dies when you ask for more fuel (throttle) or when time passes. It does sound suspiciously like fuel starvation either from a pinched line or some other reason. Maybe you can borrow a fuel pressure tester or purchase one. I had a friend who swapped out an engine in his Jeep before realizing he had a pinched fuel line by the tank! A tester will tell you the actual pressure. Double checking the fuel lines from back to front will tell you if that pressure can be maintained with enough volume through the lines.
Too much pressure is as bad as to little. Run the fuel pressure test. I see you have replaced the pump but no fuel pressure test. You can get the tool from the tool loan program at any good parts store. Also do you have a multimeter?
It sounds like you have hit it all. My thought is that where the lines rout over the top of the tank and then through the frame member over to the fuel filter is a b**ch. You might try and let the tank hang a bit and try to see if it changes anything. Also given that you have shot-gunned parts at it you may have gotten a bad new part. (Not the first time nor will it be the last). Fuel pump pressure test as well as a volume test.