It could be the anti-drain back valve in the fuel pump. What it does is exactly what the name implies, it keeps the fuel from draining back into the tank when the engines off. It could be bad, and the fuel pump just has to take some extra time to get the fuel back up to the engine. I'm assuming you don't drive this Jeep very often being it only has 42k miles, so I wouldn't be surprised if that was it.
What you can try is just turn the key to the on position and leave it there for 3 seconds; do this a couple of times and then start it. This will prime the fuel system and get you going.
1990 YJ-The wheeler
2015 JK- The DD
i am the 2nd owner. the PO didnt drive the jeep too often. i on the other hand use it as a daily now.
hot, warm or cold the problem is the exact same symtoms.
could the drain back just have gone bad from previously sitting for long periods of time?
i have owned the truck for 4 months now and up untill a few weeks ago all as been well.
The possibility that it's a leaky anti-drainback valve inside the pressure regulator atop the fuel pump is high in my book. This is a common enough problem with Jeeps that it's certainly in the top 10 most common problems asked about here on JF.
A quick way to know if that valve is the likely problem is this... the next time you believe the Jeep would be slow to start, do this before starting it: Open the hood and look at the fuel rail that is connected over the top of the fuel injectors. On that fuel rail is a Schraeder valve which is exactly like an oversized tire stem valve. Unscrew the black plastic cap and after placing a towel underneath, push on the valve stem and see if the fuel is still under pressure. If the fuel spews out under pressure and takes probably ten or more seconds to drain, the anti-drainback valve is fine and not leaking. But if the fuel barely dribbles out, before attempting to start your engine, odds are that fuel pressure has been drained off by the anti-drainback valve.
If the fuel pressure inside the fuel rail is strong and the engine still doesn't start quickly, the anti-drainback valve is not the problem. If the fuel barely dribbles out of the Shraeder valve on the fuel rail and the engine has the slow-start problem, I'd have to assume its the anti-drainback valve that is allowing the fuel to drain down out of the fuel rail which will cause a slow start.
The reason it starts faster the second time is that the fuel pump probably had enough time to get the fuel back up to the fuel rail by that time.
On the same port that Jerry just spoke of, you can buy or rent a fuel pressure gauge from your local parts store and connect it there for exact psi readings. I did this while chasing an issue unrelated to yours and ended up permanently installing a nice glycerin filled gauge. Not only does it look really cool, I can see my exact fuel pressure at any time. Good luck.
Im having a similar issue. My 2000 TJ acts like it wants to start. It cranks just wont turn over. I checked the starter and relay and those are up to spec. checked battery...fine. I had a No Bus code at one time, disconnected battery checked all connections and inspected grounds and code went away. seems like it only happens when it gets hot. Is there anyway it could be my solenoid or starter relay? Ive got 102k on it and recently had Transmission rebuilt. I have no idea where to begin looking. was told it might be a safety switch issue???? I disconnected battery and starter, left it for 2 or 3 days went out and it cranked right up. Drove about 20 miles went to a ball game came back out and it would not turn over. Can anybody shed a little light on this issue? Im wandering around in the dark