2005 TJ 4.0 won't start

[AH64ID]

Need a little help on where to start with this one. 2005 4.0L ~`125K miles

Jeep sat parked for about 2 weeks and then the wife was going to drive it to work. So she pulls it around front, shut's it off and goes inside. Next morning it won't fire. It cranks, and twice idled for about 1-2 seconds.

Now it just cranks and won't fire. It doesn't even sound like it's trying to fire.

-Battery is good, but put a charger on it just to be sure.
-fuel is good, 9 miles on a full tank
-no codes... it did throw a P0522 (oil psi sender) but that cleared itself after a longer engine crank
-don't see any blown fuses
-swapped fuel pump and starter relays
-I can very briefly hear the fuel pump at key on, then it goes off. That's normal on my other rigs, so I assume this is normal too?

So I am at a loss. Any idea's where to start?

I would think a cam/crank sensor would throw a code... right?

Thanks

 

[Daryl]

Remove your air cleaner tube at the throttle body. Have a helper crank the engine over while you spray a small amount of starting fluid in the throttle body. If it starts you have a fuel delivery problem. If it doesn’t start you have an ignition problem.

 

[AH64ID]

After spending a little more time listening at key on, I am not sure I am hearing the fuel pump.

I had the wife cycle the key while I was back by the fuel tank, and the only noise I hear is coming from the engine bay.

I'm leaning more towards a fuel pump.

Is there a good place to disconnect the fuel line and see if the pump is pumping?

 

[AH64ID]

Remove your air cleaner tube at the throttle body. Have a helper crank the engine over while you spray a small amount of starting fluid in the throttle body. If it starts you have a fuel delivery problem. If it doesn’t start you have an ignition problem.

Yeah that's the plan for tomorrow evening.

I had too much going on this evening to spend more than a couple minutes on it.

Got it towed out back to the shop and will tinker a little tomorrow evening.

 

[Chris]

Just because you put a charger on the battery doesn't mean it's good. You need to have it load tested (which any auto part store will do for free). There's a chance it's got enough juice to fire up, but once fired up, it quickly drains.

Is there fuel in the tank? One time this happened to me (the same symptoms you describe) and my gas gauge was showing half a tank, but I came to find out the gauge had just suddenly stopped working, and my tank was empty. Man did I feel like an idiot afterwards! Always check the simplest stuff first, seriously.

If a sensor was bad, it would typically be throwing a code. Have you scanned it to see if there are any stored or pending codes?

I'm betting it's battery related, seriously. Like I said, just because you charged it doesn't mean a single thing unfortunately.

 

[AH64ID]

As stated in my first post there are not any codes, and the tank has 9 miles on it.

Battery is good, this I’m 110% certain of. Cranking rpms are proper, with live OBDII data.

With the lack of codes I’m leaning towards fuel delivery. I’ll get a little time to test spark tomorrow.

 

[Goatman]

Swap the relays back and see if you hear the pump come on now. Once (different vehicle) dropped the tank to replace the fuel pump assy. and when all was back again got a crank/no start problem. Pump wouldn't prime. Pulled it back out and bench rest 100%! Back in and crank/no start again. Friend stopped by and pulled and reinstalled pump fuse. That's all. Pulled the fuse, put it right back in. Truck started right up! Go figure. I had never even been near the fuse panel.

 

[AH64ID]

It was indeed the fuel pump.

I installed a new Bosch unit yesterday and all is well.

The tank was nearly full, so I intended to drain it but couldn’t get a hose into the tank. With a floor jack and a piece of plywood I was able to easily deal with the full tank. Job took less than 90 minutes.