Jeep LS swap for the LJ

glockman

I hate Jeeps
Location
Pleasant Grove
You may already know this but just FYI in case others are reading this and looking to do a similar swap.

Since you're reducing wire count in your loom be very cautious of ground wires. Do not eliminate or combine grounds. GM had some issues early on as they were transitioning from their Gen III to Gen IV engines and electronics where they used a common ground. With their earlier iterations it wasn't an issue but with the more sensors they were adding and relying on for data as well as multimale servos such as throttle body, purge, etc. they quickly realized that one ground wasn't enough of a current path and were experiencing limp mode symptoms. This was solved by adding multiple grounds but unfortunately one of the more common things I've seen when people try to reduce wire count is these grounds being combined. Even on some aftermarket standalone wiring harnesses for street rods/race cars I see this and it is not a good practice because if several servos are being activated it can cause just enough of a voltage drop to put the ECM into limp mode. These systems are monitoring so precisely that even a few millivolts of voltage drop or out of parameter and it will either throw a code or worse put it into limp mode. This is also why the USEPA guidelines specify that even the factory wire harness must be intact as it is an integral part of the emissions system nowadays.

Just an FYI.

Mike
The only grounds I removed were the branch legs from the main harness (trunk) ground to specific sensors that were being removed. Good reminder though.

Grounds are often overlooked and in my experience are the cause of the majority of automotive electrical issues.
 

glockman

I hate Jeeps
Location
Pleasant Grove
I got the heads back from the machine shop this week. Also got new head gaskets, GM fuel tank pressure sensor and 98 camaro (3 wire) coolant temp sensor from Rock auto.

My SYE kit from JB conversions showed up today also. I still need to locate a decent transmission. That is the last of the major components.

I've been pouring through wiring diagrams and creating a plan for what wires need to go where between the two harnesses. This should make the wiring a little quicker once I start into the jeep.

Since my jeep is an 06, it has a SKIM key. I am not sure if I should bypass the entire Jeep PCM and just run the engine stand alone, ie send KO signal to a fuel pump and starter relay without going through the PCM. As I mentioned, I want to try and contain all my wiring in the Jeep factory Fuse box.
The stand alone setup requires those two relays I mentioned. Looking at the diagram, the factory starter relay gets power from the ignition and gets ground from the PCM once all the SKIM and automatic shut down circuits are satisfied. Is there any reason not to just ground the relay and allow Key'd start to activate the starter? I would also need to bypass the PCM for the fuel pump relay. It would be easy to hot wire but these jeeps aren't that complex to begin with.

I'll start mounting heads and intake manifold this week and layup my modified harness to see if I want to change any legs. My goal is to have the harness complete (engine side) before I pull the 4.0. Then I'll only have 10 or so wires to connect to the jeep which should speed up the swap. I'm hoping to have the jeep on the road in a month or less from the time I pull the motor.
 
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glockman

I hate Jeeps
Location
Pleasant Grove
Got the slip yoke eliminator installed last week. Picked up a transmission yesterday. I now have all the major pieces. I have been going over the jeep wiring to see what can be removed from the Jeep PCM to clean it up ad not have massive unused wiring. Here's a taste of that.

1580160106455.png

It's really not bad. I have just been scrolling through the service manual diagrams and picking out all the PCM connectors and listing where they go and what they do.

I also went and got the emissions done today since it's due in February:D.
I will go get the A/C evacuated tomorrow and might start pulling the stock drive train.
 

glockman

I hate Jeeps
Location
Pleasant Grove
In all my research I found this thread on Tacoma world. It's the most informative automotive wiring resource I have ever seen. Check it out if you have an upcoming project and a couple hours.
 

glockman

I hate Jeeps
Location
Pleasant Grove
Finished pulling the Jeep drive train. True to form, checked 10 times and still missed the fuel line until the engine was hanging 😔.

20200129_125749.jpg

Now I'll start to pull the wires from the Jeep PCM and body harnesses that aren't needed for the ls.

20200129_140517.jpg
I'll see if I can post the Excell sheet I have for these harnesses. I copied the lt swap format and labeled every wire and if it stays or goes.
It's good to be in the doing stage.
 

glockman

I hate Jeeps
Location
Pleasant Grove
Little more progress. Jeep trans and engine are separated now.
For comparison
The whimpy 4l60e vs the 42rle. ;)
20200130_150932.jpg
Also got some more goodies from Dave's custom
20200130_133745.jpg
I've had a york compressor on the shelf for years. I am still not sure if I want to go to the trouble of keeping the A/C in the Jeep. It has no doors and a safari top as soon as the weather warms up. The York will occupy the compressor spot for the time being.
One of the holes in the head was slightly buggered so I got to use my new tap sockets. These things are sweet.
20200130_141154.jpg
Finished mock up.
20200130_142018.jpg

Also got the Jeep motor mounts cut out. I'll clean the frame and mock the new mounts tomorrow hopefully.

20200130_160117.jpg
 

glockman

I hate Jeeps
Location
Pleasant Grove
Didn't get to engine mount mock up today. Instead I got a few odd's and end's tied up and come organization of parts. It's sucks not making headway but it helps to clear some aux tasks so by my weekend I can tackle the big chunks.

I started listing parts for sale too. I sold the 241OR Transfer case in a couple hours. I owe Unstuck lunch for sure. He mentioned using the Chevy 241 in a thread some time back. For some reason I had a blind spot to using a T-case that was OEM to the rest of the drive train. Using the 241c saves a grand in adapters and tearing the trans down to install the right output shaft. It also allowed me to sell my 241OR $$ and it makes transmissions a consumable since they are cheap and require no modification to install in the event of a failure, which according to the internet is often.

Some numbers on where I am cost wise for those that are interested. I know there is a wide range of numbers thrown around on how much an LS swap cost. I've often seen numbers ranging from $3k to $15k. Here is what I've been able to pic up with some luck and hours of interweb searching.

5.3 Engine (KSL)- $800
4L60E (KSL)-$200
T-Case (junkyard)-$150
SYE with 1350 flange (JB Conversions) $450
Radiator and fan (KSL) $130
Engine mounts (Daves customs) $200
Corvette oil pan (KSL) $50
Corvette exhaust manifolds (KSL) $50
Head checked and decked (strausburg machine) $150
Head gaskets and coolant temp sense (rock auto) $90
York Mount (Daves customs) $150
GM PCM Mount (Daves customs) $60

Total of $2500

Sold the T-case for $1500.

I still have the jeep engine, trans and several other parts I plan to sell and at this point I'm into the swap roughly $1k. Not too shabby.
I still need to buy a T-case cable shifter, trans mission shifter, drive line mods and exhaust which will probably set me back another grand.

Sorry no pictures and a long post about money:D
 

anderson750

I'm working on it Rose
Location
Price, Utah
Didn't get to engine mount mock up today. Instead I got a few odd's and end's tied up and come organization of parts. It's sucks not making headway but it helps to clear some aux tasks so by my weekend I can tackle the big chunks.

I started listing parts for sale too. I sold the 241OR Transfer case in a couple hours. I owe Unstuck lunch for sure. He mentioned using the Chevy 241 in a thread some time back. For some reason I had a blind spot to using a T-case that was OEM to the rest of the drive train. Using the 241c saves a grand in adapters and tearing the trans down to install the right output shaft. It also allowed me to sell my 241OR $$ and it makes transmissions a consumable since they are cheap and require no modification to install in the event of a failure, which according to the internet is often.

Some numbers on where I am cost wise for those that are interested. I know there is a wide range of numbers thrown around on how much an LS swap cost. I've often seen numbers ranging from $3k to $15k. Here is what I've been able to pic up with some luck and hours of interweb searching.

5.3 Engine (KSL)- $800
4L60E (KSL)-$200
T-Case (junkyard)-$150
SYE with 1350 flange (JB Conversions) $450
Radiator and fan (KSL) $130
Engine mounts (Daves customs) $200
Corvette oil pan (KSL) $50
Corvette exhaust manifolds (KSL) $50
Head checked and decked (strausburg machine) $150
Head gaskets and coolant temp sense (rock auto) $90
York Mount (Daves customs) $150
GM PCM Mount (Daves customs) $60

Total of $2500

Sold the T-case for $1500.

I still have the jeep engine, trans and several other parts I plan to sell and at this point I'm into the swap roughly $1k. Not too shabby.
I still need to buy a T-case cable shifter, trans mission shifter, drive line mods and exhaust which will probably set me back another grand.

Sorry no pictures and a long post about money:D
My wife just told me that the credit union she works for is in the process of repoing a 2012 Rubicon with a blown motor. After watching @zmotorsports build and seeing what you are doing, I am seriously considering trying to pick it up if the price is right and the condition of the rest of the jeep is reasonable.
 
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