My 1994 YJ 2.5L is reluctant to start when cold. The battery is charged, alternator works, and the starter cranks. After a few attempts to start, it will try to fire. If it starts, and I drive for a while, it will start again. Now it tries to fire but won't keep running.
I checked for corrosion on the modules/fuses in the box near the battery, and I added a bottle of Heet last time I filled the YJ with fuel.
Two things, i'm not sure if the 4 bangers have it but the straight sixs have a choke for cold starting. You simply hit the gas full throttle once and its on ..also have you checked your spark plugs and wires,I changed out my plugs and what a difference it was!
I replaced the capacitors as mentioned in the "brain surgery" thread. It didn't solve this issue, but then the symptoms are different (I figured it wouldn't hurt to replace the capacitors anyway).
The Check-Engine Light comes on when I turn the key to the "on" position. I still have to wait a few minutes before it will run when I try to start it. The longer it sits between trips, the longer it takes for it to start.
When it finally does start, it runs rough (like it isn't getting fuel), and it takes a while (even on the highway) to run smoothly.
On a 1998 ZJ with the V8 in it, the fuel pump module is combined with the fuel sending unit and a "one way" valve. Generally all these are replaced at one time rather than repaired individually. In my neck of the woods, the module costs $300. The "one way" valve is designed to keep fuel in the lines by not allowing it to "bleed back" to the tank after you turn the engine off. If that valve goes out, it does what you are saying BUT you need to check for fuel line crimps or cracks. I am sure if you had a crack, you would know by the smell. Sometimes you can crimp the line and not realize it, of course, this is depending on how you use it.
For the V8, there is a factory procedure to figure out what the culprit is, but I don't think the specs are the same for your engine. If no one "chimes in" with the correct procedure and specs for your motor, than I will post it for you... unless you want me to do it anyway. It is up to you. Good luck and don't worry. We will have you going before winter sets in.
Check out "YJ V6 Conversion" if you want to see a frame up restoration of my 1992 YJ.
Check out "WWII Jeep Photos AND Restoration of..." if you want to see the original JEEP in action...
I have a '94 YJ 2.5l that has been giving me trouble starting in the cold. Block heater works, I have run fuel line anti-freeze through it and I know it's not the battery; I have power, it turns over but consistently will not fire UNLESS the check engine light and shift indicator light are on....I try to start it and after a few cranks, these lights flicker on, I turn the ignition off, try again and pump the gas twice, and it fires up reluctantly. Anyone have any thoughts on what the problem might be?