Starting Issue. Help Needed.

[jcarabeau]

Hey guys! So I'm having a problem with my 04 Liberty and am hoping you all can help me out. So here is the story...

I do deliveries for OrderUp part time for some extra cash. When I start the Jeep cold, it starts up no problem. After driving around for a bit (usually 1.5 hours) the Jeep starts to struggle to start up. Around the 2 hour driving mark, the Jeep will crank, turn over, and then stall. I'll try to start it a couple more time and it'll crank but then not turn over. Eventually it won't crank. I have to wait about 30 minutes then it will start up again. At first I thought it was a battery issue, but had that checked out. Battery and alternator are good. Then I thought it was a coolant issue. Checked that all out and still had the same problem. So now, I'm not sure where to look. Fuel pump? Over heating issue? Anyone have this problem? Any suggestions?

Thanks in advance for any help. This Jeep has a lot of miles on it so I'm not looking to spend a lot of money to get it fixed. I was hoping to have it last through the winter (4WD) then look to get something new.

 

[nullptr]

First step is to go to Autozone and have them try and pull codes.

 

[ouroboros]

Or do the Libertys code scan on itself... Key on and off three times ending in on and it'll show codes where mileage should be.

 

[Billwill]

This is a very common problem with the cam sensor or crank sensor failing when hot.
Codes are not always posted but you can give it a try.

You can test the sensors by measuring their resistance when cold then measure the resistance while heating the sensor up with a hairdryer....the resistance should not change!

Replace with genuine OEM parts!

 

[jcarabeau]

So I did the Jeep code check. After turning it on and off 3 times it said "done" where the mileage is usually shown. No Pxxxx codes or anything came up.

 

[jcarabeau]

Also, the check engine light isn't on. I spoke with the repair shop I've taken the Jeep too before and he mentioned needing a new fuel pump ($600-700 parts and labor). I'm hoping that's not it. I would think the Jeep wouldn't have problems starting all the time if it was a fuel pump problem. It really only has problems starting after it runs for a couple of hours.

 

[CactusJacked]

Yes it could be the fuel pump, overheating the more you use it. But that wouldn't explain a no-crank issue (just a click or nothing with turn of key).
Btw, "crank" and "turn over" mean the exact same thing, the action of the starter. You're using them as different terms.

 

[jcarabeau]

I was under the impression crank is the initial action of turning the key and the "chug" to start (still holding the key in the ignition) and then turning over is when the vehicle actually starts (releasing the key and the vehicle runs).

If I keep trying to start the Jeep it will get worse and worse until it eventually won't crank. Then I'll wait 30 mins are so and it will start right up.

 

[jcarabeau]

Would a fuel pump issue show up in the codes or only when I can't start it?

 

[jcarabeau]

Also, the Jeep never stalls or loses performance when I'm driving it. It only has problems when I park it and turn it off. It won't start right back up again.

 

[CactusJacked]

I was under the impression crank is the initial action of turning the key and the "chug" to start (still holding the key in the ignition) and then turning over is when the vehicle actually starts (releasing the key and the vehicle runs).

If I keep trying to start the Jeep it will get worse and worse until it eventually won't crank. Then I'll wait 30 mins are so and it will start right up.

You're not alone. Back in the olden days (before my time even), cars didn't have an electric starter. There was a hand crank in the front that you pulled up on to turn over the engine, and eventually the engine would start. Crank was the mechanism, turning over was the action, the engine firing and running on it's own was the final reaction. So, crank (now with a starter) and turn over has become to mean the same thing since it's from one action of the key.
But back to the matter at hand. lol. It almost sounds like you may have a fuel pump/supply issue, and a starter that could be on it's way out, both getting their fill of being heated/overworked. Been there, had em both, but not at the same time. See if Autozone has a fuel pressure gauge you can borrow through their tool loan program, hook it up and see what you have going on.

 

[kage860]

I'm going to guess crank position sensor. Only because I worked on a Saab that would not spark without a good CPS, and they tended to stop working when hot before failing completely.

 

[Cpt Marvel]

"Engine cranks but will not start". Basic troubleshooting terminology. Means you turn the key to the "start" position, the crankshaft rotates but the engine won't start. "Cranks" is the same as "turn over". Mean while, back at the ranch.....,, back in the old days in the army we had old dodge and Chevy trucks that for some inexplicable reason would start fine when cold, but not when warm. Traced it down to some ******** interlock in the starter motor itself. Problem cured. Was no way to test or check it. Just threw in another starter and it went away. Of course, we didn't have to pay for anything except skinned knuckles.