After replacing my flywheel & head-gaskets, I can't get this 2012 LR4 to start. I have compression, spark, and fuel. I tipple checked timing. The fuel tank is nearly empty, showing 56 miles to empty. Will add fuel and test. It did start one morning, I let it run for 20 seconds and shut it off as I noticed the engine temp gauge spike. Couldn't start it afterwards. My temp guage is showing at the half way mark even when the truck is cold and I suspect the ECU is getting a bad read, maybe the one of the 2 coolant temp sensors got damaged during the rebuild. I believe I have some sort of electrical problem that occurred during the rebuild as this issue is new. Has anyone had problems starting due to a faulty coolant temp sensor?

 

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I am embarking on a partial rebuild on a 2011 LR4 with 120000 miles that I picked up with a hydrocarbon leak detectable in the coolant. Currently still in the tear down phase.

 

Did you ever figure out what the issue was?

I have a 2010 that I just finished rebuilding. Started, but rough and throwing ECT code so I replaced them both. Now it runs much better, when it runs, but won’t turn over if it’s too cold. Still throwing a P0117 code too.

 

Yes, I did figure it out.. but it took a while. During re-assembly, the ETC connector was inadvertently swamped with another connector- I don't recall which it was exactly, may have been a knock sensor. Most manufacturers intentionally design or position connectors in a manner to avoid plugging in the wrong wire, but in my case I had extended one wire further than it was original positioned. The tell-tale sign for me was the temp guage spiking to max, clearly the ECU was receiving bogus values. Double check you have connected the sensors to the right connector.

 

Thanks for the insight. I did notice that those connectors were awful similar while I was in there. It’s definitely poor engineering practice to have such similar connectors so close to each other.
It would be worth taking a few minutes to double check as you suggest.