Engine stalled at idle, fuel/temp went zero, won't crank

JimmyP · **Joined:** Wed Jan 09, 2019 12:39 am **Posts:** 8

Driving home after an hour drive, I was just pulling up to the house on a slight up hill when the engine stalled. Looking at the dashboard, I saw the Fuel and Temp gauges drop down to Empty and Cold. I stopped the Jeep, put it into park, cycled off the ignition, and then tried to start it. The engine wouldn't crank. Didn't even hear the starter try to engage.

I cycled the ignition key off and then to on and watched the dash lights. Seemed to start with the normal sequence, but then different indicator lights would come on as others went off. Almost as though the Jeep had simply lost its mind. Fuel and temp gauges never started reading properly again even though I had 1/2 tank of fuel and a well warmed engine.

Thinking my charging system may have failed, I went and grabbed my volt meter and found the batter to be 12.52. I asked my wife to try the start sequence and the battery went to 12.50. I heard something that sounded like it could be a relay click on the passenger side of the engine, but that was it.

I've been searching for a couple hours on the forum, but so far have only come across crank position sensor issues. However, if I understand the postings correctly, the engine would at least try to crank.

It's always so impossibly confusing until a lostjeep member explains it

thesameguy · **Joined:** Sat Oct 01, 2016 8:24 pm **Posts:** 652

Crank position sensor will keep an engine from starting, but not cranking. Running the starter is pretty straightforward - just the ignition switch, starter relay, battery, and starter. Do you have 12v at the lug on the starter? Is there 12v at terminal 30 on the starter relay?

I don't think this will solve your issue per se, since a anything relating to the starter shouldn't cause the engine to die or weight lights to illuminate, but it may give a clue.

Do you have a spare battery? Sometimes batteries can become internally damaged such that they show 12v but can't actually supply real current. It could be worth a try.

foxmiles · **Posted:** Mon Feb 08, 2021 1:09 pm

From the wiring diagram it looks like the starter relay grounds through the ECM? So check fuses, connections, and grounds. You can jump the starter relay to check that it cranks. Considering it stalled and won't crank I'd be very suspicious of something with the ECM (I'd suspect wiring/fuses/relays/grounds more than the module itself, although it is possible). I think there are some common ground issues around there?. Might check the connections on the FCM too, just in case.

Also try to pull codes if you can, it will tell you if there's a code in there or if it can even communicate with the ECM.

JimmyP · **Joined:** Wed Jan 09, 2019 12:39 am **Posts:** 8

For chasing down the wiring, is there someplace I can get the wiring diagram? Any procedural tips would be helpful. Otherwise, I'll plan to verify connectors that are supposed to be connected to ground, power is just power, and signal wires aren't accidentally grounded. I'll start with the fuses and relays - mainly because I'm lazy and that seems easy, but also cause it's sound advice

The local Napa has an OBD reader I can borrow, so I'll see what information I can gain from that.

foxmiles · **Posted:** Mon Feb 08, 2021 4:08 pm

I'm not sure if we can directly link it here, but the file name is 2005JeepKJServiceManual.pdf, and google should help you find a source with a bunch of useful information about your jeep that's probably worth downloading and keeping around.

Fuses and relays first is a very good idea. You don't know how many times I've gotten way to far into tracing wires only to find a fuse in the box was blown or in at least one case, vibrated until it cracked (not specifically Liberties, just in general).
Then check grounds next (Liberties are known for having ground issues. They look fine but have corroded enough to cause problems. I think there's a guide on here somewhere

Also, found this while looking for the thread of ground issues: http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=84861

and this one: http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=89804

thesameguy · **Joined:** Sat Oct 01, 2016 8:24 pm **Posts:** 652

If you look at the beginning of this video, you can see how to jumper the starter relay:

https://youtu.be/8mE9arD5f40

This directly powers the starter solenoid and thus runs the starter, bypassing all the electronic mumbo jumbo. This will tell you if the battery, starter, and battery cables are behaving themselves, and in general point the finger at an electronics issue.

JimmyP · **Joined:** Wed Jan 09, 2019 12:39 am **Posts:** 8

Thanks for the replies foxmiles and thesameguy!

I followed the first link that foxmiles privided and it perfectly matched my problem http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=84861. So much so, that it would be pointless to upload pictures of the problem as it was exactly the same. And the work that WWDiesel on reworking that wiring harness was inspirational. New loom headed my way.

After replacing fuse #14 on the drivers side kick panel, adding electrical tape and loom to the wire(s) over engine, and turning the key - vroom. :JEEPIN:

Summary of symptoms in case it helps someone else:

Possible cause:

foxmiles · **Posted:** Tue Feb 09, 2021 10:51 am

Awesome! I stumbled across that looking for the one about grounds and thought it sounded awful close to your issue, glad it was an easy fix! I'm going to check that loom later, if it's deteriorating I'll get the stuff and hopefully avoid this issue altogether.

Engine stalled at idle, fuel/temp went zero, won't crank

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