How To LS Swap Your TJ

Wildman said:
Read the instructions..




While yes it sounds simple IMO having to run 2 PCM's is a PITA. As far as the tach working I'm not sure about that. The emulator from Dakota Digital I'd heard was the easy way.

I'm honestly not sure why the shop that worked on GotMud rig couldn't figure out how to get the gauges working since as you said it really isn't hard.
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I have been treating the Jeep PCM like its a BCM. So right now it runs my gauges of course and I am trying to figure out how to use it to cycle the AC clutch and where it will kick on an electric fan like a XJ would. I might just put an XJ PCM in its place to have the electric fan kick on from the AC request. Also going to take all the cruise control stuff off of a spare TJ I use for beating on in the woods without much regard for its safety or mine and the Jeep PCM should be able to run it since it sees a tach, speed signal and the other needed signals for the factory cruise to work.
 
XCRN said:
I have been treating the Jeep PCM like its a BCM. So right now it runs my gauges of course and I am trying to figure out how to use it to cycle the AC clutch and where it will kick on an electric fan like a XJ would. I might just put an XJ PCM in its place to have the electric fan kick on from the AC request. Also going to take all the cruise control stuff off of a spare TJ I use for beating on in the woods without much regard for its safety or mine and the Jeep PCM should be able to run it since it sees a tach, speed signal and the other needed signals for the factory cruise to work.
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I don't know that there is the option to kick on an electric fan like on an XJ since the only TJ's that had electric fans were the 2.4 engines. It's been discussed in another thread.

Apparition said:
I may next week.

Still much of the reason I went with my AEM dash. Should read everything straight from the GM computer no emulator and no extra Jeep ECM
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No converters or emulators needed. Just as simple as hooking up some analog gauges.. Add the required sensors and BOOM you have a digital dash. And by running this dash you don't need the Jeep PCM anymore. That was the whole POINT. If you don't want the stock TJ dash you do not need the Jeep PCM as that is it's only function at that point.
 
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Wildman said:
No converters or emulators needed. Just as simple as hooking up some analog gauges.. Add the required sensors and BOOM you have a digital dash. And by running this dash you don't need the Jeep PCM anymore. That was the whole POINT. If you don't want the stock TJ dash you do not need the Jeep PCM as that is its only function at that point.
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My whole point is I didn’t want to have to swap any gauges or sensors because they are already in the GM engine so the dash I’m using plugs right into the GM harness and requires nothing else not even a Jeep pcm.
 
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Apparition said:
My whole point is I didn’t want to have to swap any gauges or sensors because they are already in the GM engine so the dash I’m using plugs right into the GM harness and requires nothing else not even a Jeep pcm.
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And AGAIN there isn't any need for a Jeep PCM if you use that digital dash. The sensors in the LS engine might even be what it needs for a signal. It isn't had to T in a oil pressure sensor if needed nor add a water temperature sensor. The fuel comes off the stock Jeep sender & your spend sensor is off the t-case...

Not everyone wants that type of dash you're using. If I was doing a LS swap I'd opt for the analog gauges before I did anything else but that is me.
 
Apparition said:
My whole point is I didn’t want to have to swap any gauges or sensors because they are already in the GM engine so the dash I’m using plugs right into the GM harness and requires nothing else not even a Jeep pcm.
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One of the little things I ran into the other day is running the Jeep CTS on the passenger head with a fitting adapter really sticks out quite a bit and I snapped the sensor right off while taking the rear passenger spark plug out since it does not allow for a lot of room to get a wrench in there. And to make things worse, putting the new spark plug in, I had a tough time getting the socket on straight to tighten the spark plug and ended up cracking the porcelain. That could have been avoided if I took my time, but I can rush the other 7 plugs without breaking the porcelain. To also add the oil and coolant were never 100% accurate, just accurate enough that I knew when there are problems.

So there are some drawbacks to using the Jeep gauges. I really like the Dakota Digital gauge cluster for TJs that is somewhat factory style that you can easily have read the info from the GM PCM through the OBD wires, but its close to $1500.
 
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XCRN said:
One of the little things I ran into the other day is running the Jeep CTS on the passenger head with a fitting adapter really sticks out quite a bit and I snapped the sensor right off while taking the rear passenger spark plug out since it does not allow for a lot of room to get a wrench in there. And to make things worse, putting the new spark plug in, I had a tough time getting the socket on straight to tighten the spark plug and ended up cracking the porcelain. That could have been avoided if I took my time, but I can rush the other 7 plugs without breaking the porcelain. To also add the oil and coolant were never 100% accurate, just accurate enough that I knew when there are problems.

So there are some drawbacks to using the Jeep gauges. I really like the Dakota Digital gauge cluster for TJs that is somewhat factory style that you can easily have read the info from the GM PCM through the OBD wires, but its close to $1500.
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My goal is to get rid of as much jeep stuff as possible. Someday I'll get around to seeing if I can.
 
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Minitucking said:
Great write up! I am in the middle of a Gen 5 Swap at the moment. This helped clear up a few questions i had.
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Thanks! I am glad it helped. I am curious about your build since ill be eventually throwing a Gen V and 6L80 into my LJ.
downthepines said:
Really starting to wonder what a 400 hp tj would feel like. Its a rabbit hole.
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I am amazed at how much easier it is to merge on to the highway when comparing my LS TJ and stock LJ.
 
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I noticed that since I did my swap I only get heat from the defrost vent. I searched and found I need to somehow connect the tiny vacuum line that used to connect to the Jeep manifold. How have people done this with an LS Swap?
 
Sj's TJ said:
I noticed that since I did my swap I only get heat from the defrost vent. I searched and found I need to somehow connect the tiny vacuum line that used to connect to the Jeep manifold. How have people done this with an LS Swap?
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What intake manifold are you using? I used a TBSS and there was a small port on the passenger side to hook up the vacuum source line. I think regular truck manifolds are roughly same location. Basically you need to replicate the factory lines and connect the end with the red arrow to a small nipple on the intake manifold. Keep in mind there are check valves along the factory vacuum lines.

IMG_8569.jpeg
 
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XCRN said:
What intake manifold are you using? I used a TBSS and there was a small port on the passenger side to hook up the vacuum source line. I think regular truck manifolds are roughly same location. Basically you need to replicate the factory lines and connect the end with the red arrow to a small nipple on the intake manifold. Keep in mind there are check valves along the factory vacuum lines.

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Thanks for the diagram. I'm using a truck intake from an 02 Tahoe. I saw a video that shows a little port on the passenger side that you just twist off. Another issue I have is I no longer have item 8 from the diagram. Do you think I can just plug that end?
 
Sj's TJ said:
Thanks for the diagram. I'm using a truck intake from an 02 Tahoe. I saw a video that shows a little port on the passenger side that you just twist off. Another issue I have is I no longer have item 8 from the diagram. Do you think I can just plug that end?
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You can cap off/plug the hose that vent to your vacuum canister but just know that when you accelerate your vents might switch back to defrost. The canister is there to supply a reserve of vacuum when needed. Do you not have room for one under your battery tray anymore?
 
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Wildman said:
You can cap off/plug the hose that vent to your vacuum canister but just know that when you accelerate your vents might switch back to defrost. The canister is there to supply a reserve of vacuum when needed. Do you not have room for one under your battery tray anymore?
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The room is there, I think I mistakenly threw the canister away. I'm glad I can cap it off if I can't find it. Thanks for the info!
 
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Sj's TJ said:
The room is there, I think I mistakenly threw the canister away. I'm glad I can cap it off if I can't find it. Thanks for the info!
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I have been running mine capped off for awhile and its been fine. I put the AC accumulator in that space and I want to relocate the canister, but I have many other projects to deal with first.
 
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Wildman said:
The Intellitronix gauges doesn't car what engine is in the rig. It fits in the TJ dash area but uses it's own oil pressure & temperature sensors, And then just needs a tach signal and a pulse signal for the speedo.

https://intellitronixgauges.com/1996-2006-jeep-tj-led-digital-gauge-panel/

It's the same one I bought but just haven't decided if I want to use it or not yet.

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I am trying to decide between this panel and the Dakota Digital........I am not keeping the jeep PCM. Years ago I did the AW4 swap into my 2000 TJ from a NV3550. It has been wonderful having that auto... but it sort of makes the value of selling the engine and transmission less desirable if I don't sell it complete with the modified harness so it will work well for the next guy.

Anyway, the cost of the Dakota digital panel and even the VHX gauges is a lot more than this Intellitronix panel and that is what is hanging me up. How well does this gauge work with a LS/4l60e swap in the TJ?
 
XCRN said:
Will add pictures, typed this on my computer and all my photos are on my phone so ill go back and edit them in. I will also be adding info as subjects come up and I do more of these.

So you want to go to the dark side discombobulate your TJ and throw a LS motor in your rig? Well its not that difficult and I am going to try and best explain how to do it. Most of my knowledge comes from my personal daily driver 2000 Jeep Wrangler that I have put on roughly 30k miles in the almost 3 years I have had this finished this swap. On this TJ, it has a 5.3 LM7 from a 01 Silverado but I had backed it both with the original NV3550 that I probably broke at 175k miles and now currently one of the brand new AX15 transmissions with 2 different adapter. I also had 2 different EFI systems, Terminator X Max and stock DIY standalone. This could be almost entirely a bolt on swap with little cutting and fabrication needed if you buy the right parts.

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What size lift kit was needed? And any body lift?
 
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