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LS swap guys! Need some input!


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So I've been gathering a few parts for an LS swap into an MJ for a few years now.

 

I've got a 1999 LQ4 6.0L

200,000+ miles, pretty ugly and rusty but I think it'll run. I got it to fire off some starting fluid (fuel lines to pump are rusted away)

 

Since It needs gone through my plan is now to build it to 500hp, which should be pretty easy for cheap. Gonna throw a turbo on it and a cam and valves n springs for sure probably.

 

I've got full mj swb exhaust with Novak headers for it but I think ill go straight turbo from the start.

 

I've got novak motor mounts and radiator and some fans.

Got a 2wd 4L80e to replace the 4wd since it's going in a 2wd eliminator.

 

Now the main thing I need help with is the wiring harness and computer. I need to pull the motor and see exactly what I have but I'm looking at the Holley Terminator X setup.

 

I'm wondering if this completely replaces all the wiring harness and computer or not.

 

Any input on anything is appreciated.

 

It can't be that hard. Lol

 

 

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I've done two LS swaps (CJ and LJ) but used the factory harness and computer both times.
I just didn't wanna do that and pay to have someone make a standalone harness and flash my computer then have to have someone tune it everytime I change something for $100 a tune.
The Terminator seems cheaper in the long run.

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I would definitely go with the Terminator X I did the harness merge on mine. Very time consuming. I bought a PSI Conversions harness and PCM. The Holley has far better self tuning capabilities in my opinion, It will end up costing roughly the same. Plus the PCM module is tiny compared to the stock GM one so you can easy mount it in the cab. I love the LEDs that tell you sensor status. I am not sure if it support AC. But you can do that without the PCM. All you need is to trigger the fans. It will also support Nitrous and turbo setups.

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I'll have to email holley to figure out the right kit.
I don't need ac or anything fancy. It'll probably be about like my cummins mj as far as jeep wiring simplicity. Except on this eliminator I won't have power windows or locks I don't think. Not sure yet. But that has nothing to do with engine wiring.

Since thus swap had been done a million times I'm sure there's plenty of write ups on it. Just not a lot of people use the early early lq4. I just happened across this whole truck for $400. I can part out and scrap the rest of it for that plus some.

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On 4/4/2021 at 11:08 AM, krustyballer16 said:

I'm also wondering if I need to get a drive by wire setup for the holley. Cuz mine is drive by cable now

Sent from my SM-G973U using Tapatalk
 

DBW vs DBC- this comes up all the time in forums and FB pages.  One thing about DBW, the entire throttle blade acts as the IAC.  Because the throttle blade is giant compared to the tiny air passages of a traditional IAC, it can react more quickly to changes- might be important if you are planning a cam swap.  Here is some interesting reading:

http://bdturnkeyengines.com/dbw-water

 

I will say that modifying and mounting the DBW pedal in my CJ felt like it was more work than installing the motor.

 

At the end of the day, I'd use whatever your motor comes with.

 

 

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The drive by cable is easier, the tune is much easier as there is none of this silly torque management you get and have to tune out with the DBW. Cruise is easier with DBW. With DBC you will need the cable servo module to make it work. Not hard but the servo box is pretty huge.

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I have the terminator x on my swap. Absolutely great system. Super easy to wire in, took 10 minutes to program, and it fired up almost instantly the first time it ran. It's self learning so the more you drive the better it gets. Plus the software for custom tuning is free. I havent dabbled in that yet, the self tune is very good so far. It also has options for power adders so turbo-ing is simple in that respect. 

 

I gutted everything to do with factory engine management except the fuel pump and alternator. Those 2 are the only things I tapped into. Terminator x has its own fuel pump output wire so you can do that, but I just kept the factory pump signal with key on. The LS alternators are 1 wire "on". Just hook that up to the factory "on" wire. It's all in the same plug on the factory harness. All lights, dash, and factory accessories are still on factory harness. The terminator has a couple options for what style LS you have (truck, car, reluctor wheel, etc)

 

I did cable actuated throttle body. I didn't want to mess with a new pedal and I like the feeling of an actual cable. 

 

I am very glad I dropped the coin on the terminator. I researched A TON on all different engine management stuff and I always came back to the terminator x. You're going with an auto so you can get the xmax for transmission controls. It has so many features and outputs to control fans and other stuff and the "dash" is very awesome. It's alot of spaghetti when you lay it out but it's all labled and everything is in the right spot. My ONLY complaint is that because it's meant for really any vehicle there is a lot of extra wiring to hide. But I just looked it under the dash. I completely hid the ecu behind the lower dash trim and all the wires are hidden under the dash. Highly recommend it.

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