94 ZJ 5.2 into a 86 MJ

[shelbyluvv]

I am currently in the process of converting a 86 MJ to V8 power. I have the MJ and the ZJ already.

I have a crap load of questions. I wanted to post this in the drivetrain section but it would not allow me.

A little about me. I am a 18 year career Marine. I am a 3529 Motor T Maintenance Cheif. I recently completed a 97+ conversion on a 89 MJ that I sold. I have been playing with Jeeps since 2002 and been turning wrenches for over 20 years. I have a pretty good understanding of most things automotive.

Now onto the Z/MJ,
I want to keep the Magnums wiring in the engine bay and the MJ's wiring and dash stock appearing. I plan on picking up a 94-95 XJ dash and wiring for this conversion. I think with having the donor harness closer in age it will make re-pinning the fuse box a easier process. I will not be using any power windows or locks on the MJ. That is more wiring than I need and the truck does not have them now anyhow.

Which wires are needed strictly for the engine to run without any codes being thrown?

I want to elimanate all the ABS, air bags, and keyless entry stuff. Is there a way to chop all the stuff out and just keep the bare bones basic harness?

What I am looking for is the engine to be sitting on a run stand running with a stand alone harness. Is this possible with the factory harness? I plan to use the ZJs fuel tank and emission equipment as well. Keeping it smog compliant is a must.

I will also be retaining the ZJs 46RH. Does it need any special wiring besides a NSS?

I know I can swap a 4.0 in and be done with it. I could build a 4.5-4.7 stroker with less aggravation. What can I say I am a glutten for punishment. I have $600 in the project this for with the purchase of the MJ and ZJ. I say why not!

Thanks for having me aboard and I look forward to completing the conversion with MCs help!

Bo Kennedy

[downtowncb]

You need to ask Tommy, he used his ZJ's drivetrain in another Jeep build.

http://www.mallcrawlin.com/forum//sh...ad.php?t=18646

[shelbyluvv]

You need to ask Tommy, he used his ZJ's drivetrain in another Jeep build.

http://www.mallcrawlin.com/forum//sh...ad.php?t=18646

Thanks, I sent him a PM. He is semi local to me as well.

[Jrgunn5150]

Do you already have the ZJ? Because otherwise tuning is alot easier with LS series engines.

[shelbyluvv]

I do have the ZJ already.

I know a Chevy is easier. They even make motor mounts for the conversion. But, I am a die hard MOPAR man and could never put a GM motor in my MJ.

[IndyZJ]

I do have the ZJ already.

I know a Chevy is easier. They even make motor mounts for the conversion. But, I am a die hard MOPAR man and could never put a GM motor in my MJ.

They came with GM motors (2.8)... and you're going to put a Chrysler motor (Magnum) and trans in your AMC. There's a reason everyone swaps in GM drivetrains. To each his own, though.

The swap has been done quite a few times. Check Jeeptech's very recent (abandoned) 5.2 swap thread. There is some good info and a few decent links in there to get you going. I'm pretty sure there's at least one OBD1 swap in a link I posted.

[Jeeptech01]

They came with GM motors (2.8)... and you're going to put a Chrysler motor (Magnum) and trans in your AMC. There's a reason everyone swaps in GM drivetrains. To each his own, though.

The swap has been done quite a few times. Check Jeeptech's very recent (abandoned) 5.2 swap thread. There is some good info and a few decent links in there to get you going. I'm pretty sure there's at least one OBD1 swap in a link I posted.

This /\ try searching a bit you arent the first to think of this. Also google search some YJ magnum swaps as the wiring will be simillar. Honestly though I personally would go 97 plus with everything in the mj and use a 96-98 zj wiring, ecu etc with ccd bus.

[shelbyluvv]

This /\ try searching a bit you arent the first to think of this. Also google search some YJ magnum swaps as the wiring will be simillar. Honestly though I personally would go 97 plus with everything in the mj and use a 96-98 zj wiring, ecu etc with ccd bus.

Thanks for the info Indy and Jeeptech.

I have already done a 97+ conversion on a MJ. That is old and busted now that everyone seems to be doing it. Also trying to get the gauges to read through the CCD Bus with a XJ cluster is next to impossible. There is a guy who dropped a 5.9 into his MJ with a 97 dash and has no tach, fuel gauge, or speedo. He is an electrical engineer too!

There is no way my hillbilly ass would ever figure that out, lol!

[cowboy63b]

Autometer gauges are always TITS!

once you got it running all you would need to do is figure out the gauge supply wires and do a bit of cutting and splicing and whammo, gauges work.

[downtowncb]

Haha use a ZJ cluster

[Jrgunn5150]

Thats the one and only reason I suggested the LS... Stand alone harnesses vast tuning potential... To me function is waaaaayyy more important than brand loyalty...Until someone is payin for my parts lol.

[shelbyluvv]

Haha use a ZJ cluster

I tried that. The ZJ cluster is way to long to fit in a MJ dash. I cut the ever loving piss out of my dash trying to make the ZJ cluster fit. All that did was weaken the dash enough to not hold it's shape. I think a HO era XJ cluster may use the same pot values as a 93-95 OBD-I ZJ. The only thing that may not read right is the fuel gauge and tach. I can work around the fuel gauge issues by swapping senders to a 91-95 XJ sender and pump and switching out the oil pressure and coolant temp senders. Luckily the MJ uses the feed and return fuel system like the ZJ. The tach may be a little harder to work around. I have moved a ZJ tach into a XJ cluster with little trouble. The only problem there is the font on the gauges is slightly different. This could be fixed with gauge overlay stickers.

Thats the one and only reason I suggested the LS... Stand alone harnesses vast tuning potential... To me function is waaaaayyy more important than brand loyalty...Until someone is payin for my parts lol.

I have been researching this more and I got lucky by getting the 94 ZJ. The 93-95 engine harness seems to be the easiest to make into a stand alone harness. There are claims that you can make a OBD-I Magnum run with only needing to power and ground a handful of wires. This is good news! Now to keep digging to figure out which ones!

[Jeeptech01]

Thanks for the info Indy and Jeeptech.

I have already done a 97+ conversion on a MJ. That is old and busted now that everyone seems to be doing it. Also trying to get the gauges to read through the CCD Bus with a XJ cluster is next to impossible. There is a guy who dropped a 5.9 into his MJ with a 97 dash and has no tach, fuel gauge, or speedo. He is an electrical engineer too!

There is no way my hillbilly ass would ever figure that out, lol!

Plenty of people have done the magnum swap in the TJ which has the same cluster as the 97+ XJ and have all the gauges working.

Looks like I may be back to a magnum swap. Apparently my idea of not cutting the harness isnt the same as the recycler that sold me a complete "swap".

[shelbyluvv]

Plenty of people have done the magnum swap in the TJ which has the same cluster as the 97+ XJ and have all the gauges working.

Looks like I may be back to a magnum swap. Apparently my idea of not cutting the harness isnt the same as the recycler that sold me a complete "swap".

I have seen a lot of info from Backwoods Fab with the TJ swaps. I was unaware until I started reading on Pirate that it was even doable.

I would like to try and keep the MJ's interior looking stock if possible. The 97+ swap is doable, hell I have done it. Just not the route I want to take with this truck.

The reason for me wanting to keep the MJ stock appearing is because of the rarity of it. My truck could possibly one of the very first 86's built. It is ser # 3550 off the line in 86. XJs were also sent down the same line as the MJs. If you take out the dealer demos and what not this makes my truck a very early build.

Will it ever be worth a shit ton of money? Probably not. Will it be cool as hell to have a stock looking MJ with a 5.2 in it? Hell yes!

I have owned this truck twice now. I am extremely attached to it. If I had not got such a good deal on the truck and the Grand I probably would have just stick another 2.5/AX5 combo in it and called it a day.

Thanks for everyone's input so far. It has got me excited to get this thing done.

[IndyZJ]

I take it you are wanting to keep the stock gauges? Or at least have them appear to be stock? How are the '86 gauges driven - are they all mechanical, or is the tach computer driven? I would assume everything would be mechanical, but this could get everything pointed in the right direction.

[shelbyluvv]

I take it you are wanting to keep the stock gauges? Or at least have them appear to be stock? How are the '86 gauges driven - are they all mechanical, or is the tach computer driven? I would assume everything would be mechanical, but this could get everything pointed in the right direction.

The speedo on the 86 is cable, the rest are driven by signal from the senders. I want to go with a 91-95 HO XJ cluster and interior wiring. The HO uses OBD-I (ChryCo) electronics. Where the 86 uses RENIX (Renault) based electronics which are a PIA to begin with.

[Jeeptech01]

Honestly that sounds like a solid plan. I know the idiot light vs gauge clusters interchange and only swapping the sensors is reqd.

[IndyZJ]

Honestly that sounds like a solid plan.

x2. Sounds like the easiest way to do it.

[shelbyluvv]

I think using the HO XJ gauges and wiring is going to be the best way to got about this. The pot values are the same for all the gauges. The fuel gauge is dead nuts on! The 23 gallon ZJ tank should fit like it was made for an MJ.

Now the only thing that has me worried is the factory security system on the ZJ. I think I still need to keep it with the ZJ engine harness and I don't want it.

If I get a DAK/DUR PCM will it do away with the wiring for the security system or do I need a different under hood harness?

[Jeeptech01]

IIRC there is a writeup on diasbling the security system on one of the Jeep sites. Maybe NAGCA? I know I have seen it

[shelbyluvv]

Everything I have seen says to ground the violet/yellow wire on the passenger side kick panel. I will not be using any of the dash harness so I might get away without having it in there.

I got all the ZJ wiring pulled yesterday. All I can say it that there is a crap load of wires under the hood of a ZJ.

I got lucky with my donor choice. The 46RH is going to make my life a lot easier come trans wiring time!

[Jeeptech01]

Honestly all you should need is the 2 plugs that go from the pcm to the engine and the third one gets wired into your MJ. Fairly simple IMO.

Were gonna need some pics soon.

[shelbyluvv]

Were gonna need some pics soon.

I pick up my XJ harnesses Saturday. I will be using a 93 engine and dash harness.

Once I get done replacing the soleniod pack in my WJ's tranny, I should be able to start piecing the wiring differences together.

I will have to swap a couple pin locations on the PCM connecter of the XJ harness and add the few wires to it for the overdrive, 7 and 8 injectors, and the purge soleniod. Other than that it is pretty much plug and play. They way it is looking I will not be using very much of the ZJ harness at all.

I will try to get some pics of the rigs for y'all in the next couple days.

[Jeeptech01]

I would think it would be much easier to use the ZJ harness????

[shelbyluvv]

I would think it would be much easier to use the ZJ harness????

I thought using a ZJ harness was the way to go too.

But, I would have to totally split both the XJ and ZJ harness, remove all the wires from the ZJ harness that are not compatible with the XJ dash harness, and replace them with the wires from the XJ harness. I plan on retaining my 86 steering column and HVAC system.

It is much easier to retain the complete XJ engine and dash harnesses intact and add the few extra wires for the injectors and purge.

Additionally, by keeping the XJ wiring complete I get to have a factory looking engine compartment and a stone stock interior.

Ultimately my goal is to have the truck look like it was built by Jeep in the 90s.