It's Time to SUPERSIZE Moby - MoTech 6.2L LS Jeep Motor Swap

wayoflife

Administrator
Staff member
Well, had an interesting thing happen today. Out of nowhere, the temp gauge on our dash stopped working - or, I should say, it still had a signal but never went above C. When you start the engine, the needles would go up a bit but just kind of sat there at C and then dropped again when you turned it off. Well, trying to make our way back home anyway, we could hear the fan going constantly but then, it went out too and just as we pulled up our street, I could start to smell coolant. By the time I pulled into the driveway, we were definitely overheating. A quick visual check showed all the wires to the temp sensors to be in place but, I'll need to wait till things cool down to give them a better look. Either way, it looks like we're gonna need to tear things apart to install a new fan and track down this problem. What a bummer.
 

Sithwindu

Member
Well, had an interesting thing happen today. Out of nowhere, the temp gauge on our dash stopped working - or, I should say, it still had a signal but never went above C. When you start the engine, the needles would go up a bit but just kind of sat there at C and then dropped again when you turned it off. Well, trying to make our way back home anyway, we could hear the fan going constantly but then, it went out too and just as we pulled up our street, I could start to smell coolant. By the time I pulled into the driveway, we were definitely overheating. A quick visual check showed all the wires to the temp sensors to be in place but, I'll need to wait till things cool down to give them a better look. Either way, it looks like we're gonna need to tear things apart to install a new fan and track down this problem. What a bummer.

Big time bummer! Hopfully it's a easy fix, did yall ever go to the 3.6 fan to help with cooling issues?
 

jmatta33

New member
Eddie are you glad you went with the LS over a hemi? and what was you biggest deciding factors in the choice ?

after market parts, no over heating issues, better fit. There are several reasons to go with the LS over the Hemi especially if you have the 3.8L in your JK.
 

MTG

Caught the Bug
Well, had an interesting thing happen today. Out of nowhere, the temp gauge on our dash stopped working - or, I should say, it still had a signal but never went above C. When you start the engine, the needles would go up a bit but just kind of sat there at C and then dropped again when you turned it off. Well, trying to make our way back home anyway, we could hear the fan going constantly but then, it went out too and just as we pulled up our street, I could start to smell coolant. By the time I pulled into the driveway, we were definitely overheating. A quick visual check showed all the wires to the temp sensors to be in place but, I'll need to wait till things cool down to give them a better look. Either way, it looks like we're gonna need to tear things apart to install a new fan and track down this problem. What a bummer.

You jinxed yourself at the S&G. :yup:
 

wayoflife

Administrator
Staff member
Better home than on the trail. Hopefully you didn't damage anything

Ain't that the truth!! :whew:

Big time bummer! Hopfully it's a easy fix, did yall ever go to the 3.6 fan to help with cooling issues?

Unfortunately, no - not as of yet. The 2012-up 3.6L fan would just bolt up and work on our old 2007 computer. Motech is working on a fix for this and we were going to have it installed the next time we stopped by.

Eddie are you glad you went with the LS over a hemi? and what was you biggest deciding factors in the choice ?

Oh yeah. We now have close to 40,000 miles on this motor and really, this has been the first real hiccup we've had. We did have one other early on due to a wiring issue but, after that got resolved, we've pretty much had no issues with the motor.

As stated, the LS is still lighter, gets better MPG, doesn't require you to beat the crap out of your firewall to install, doesn't have the over heating issues that most of the HEMI's I've seen have, parts can be found everywhere and most importantly, it can be tuned. HEMI's are awesome motors but you can't tap into them.
 

wayoflife

Administrator
Staff member
You jinxed yourself at the S&G. :yup:

Geeze, no kidding :rolleyes2:

Bummer indeed. Hope it's a simple fix.

It might be something as simple as a bad temp sensor. I've been talking to Motech and they're going to send me a Bluetooth scan tool that I can use with my iPhone to help isolate the problem. Fortunately, I have other Jeeps so, Moby can just sit and rest a bit. :yup:
 

wayoflife

Administrator
Staff member
Okay, I finally found some time to work on Moby and here's where we're at. Motech was nice enough to send out an Aeroforce Interceptor gauge so that I we could find out what's going on. The first thing to do was to check the what the GM and JK temp sensors are seeing. With the motor off, this is what I was showing...

GM temp sensor.
IMG_0167.jpg

JK temp sensor.
IMG_0166.jpg

Of course, these should be reading the same or close to it and it sure as hell isn't 375°F.

The next step was to just unplug the JK temp sensor and check again as that should give a value of -41°F or there about and that should indicate that we just have a bad sensor. Unfortunately, after doing that, I still showed 375°F. Guess I have a project on my hands.
 

10frank9

Web Wheeler
Well so much for an easy fix. I would like to see what the problem actually is, I'm sure you'll keep us posted once you figure it out. :idontknow:
 

jedg

New member
Well, heck. I didn't realize the JK temp sensor is still used. I've all but stopped monitoring the JK OBD and just watch the GM information. I'll keep this in my bag for future knowledge.
 

Linebacker

Caught the Bug
Was looking closely at the AeroForce gauge...Made in the USA. How cool is that!:thumb: Hope it's a fairly quick fix.:yup:
 

wayoflife

Administrator
Staff member
Well so much for an easy fix. I would like to see what the problem actually is, I'm sure you'll keep us posted once you figure it out. :idontknow:

Working with Motech and I'm sure we'll get this figured out. We had a similar issue way back when and were able to trace it back to the our routing of the wiring harness. When we took Moby to Motech back then, they were able to find the issue quick and fix it. Robbie is going to walk me through the process.

Well, heck. I didn't realize the JK temp sensor is still used. I've all but stopped monitoring the JK OBD and just watch the GM information. I'll keep this in my bag for future knowledge.

Oh yeah, you have 2 sensors - one for the JK and one for the GM computer. It's how you get to still use your JK dash gauges, fan, AC, etc.

Was looking closely at the AeroForce gauge...Made in the USA. How cool is that!:thumb: Hope it's a fairly quick fix.:yup:

It's a nifty gauge and I like it. We're on it now and I'm sure we'll get it fixed soon. I was just planning to head out to KOH soon but, can't go anywhere till one of my Jeeps is fixed :crazyeyes:
 

jedg

New member
Oh yeah, you have 2 sensors - one for the JK and one for the GM computer. It's how you get to still use your JK dash gauges, fan, AC, etc.

Makes sense. I had assumed that the feed to the gauges was based off the GM sensors with some form of calibration/translation occurring along the way.
 
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