NYWheeler...

[XEON]

Well I have been researching some engine swaps. Just got a question...

When you put your chevy in, how did you wiring the engine to work with the exsisting wiring like for tail lights steering colum gauges and other stuff?

Thanks 8)

[NYWheeler]

For me it was real easy but I work with 12volt electronics for a living. Most of the factory wiring actually stays in the jeep. Once I removed the computer harness there was only a handfull of wires I had to rewire. You can use the existing gauge wires and sendin units with the new motor to get your gauges working. It also depends on what motor you are using. Carb or fuel inj, factory or aftermarket harness, etc.

[XEON]

Yea I guess you are right. There are really not too many wires in the YJ thank god :)

So I would just basically have to wire up gauges and some ignition...

I am looking into GM v6 4.3L Vortec out of like an s-10 or a blazer. Fuel injected and stuff. I might do what this other jeep guy did. GM v6 ax-15 np231 and bam instand much faster and stronger jeep :)

[XEON]

Also get a ford 8.8 in the back...

[sentinal02]

There are really not too many wires in the YJ thank god :)

have you every looked in that 1.5" thick wire loom running across the top of the firewall :lol: i had to go through a dozen of the wires in there and pull the harness off the computer to check continuity just to fix my starting problems after the PO did one hell of a hack job when they dropped in the rebuilt engine. i found the WOT switch and the CTS connected to each other but not the computer, the O2 sensor disabled, and the MAT sensor wired half to the computer and half to the power steering pressure switch :shock: no wonder why it wouldn't start in the cold :lol:

as far as swaps go though, the main thing is the gauges. like NY said, things like the body lighting, etc stay put since they're really separate from the engine harness. it's not as hard as it looks as long as you can read a wiring diagram and have both the one for the jeep and the one for the engine you're swapping in.

[NYWheeler]

Once you remove the computer harness there are very minimal wires left in the engine compartment. Its realy not that bad. Its also alot easier when you use an aftermarket fuel injection harness rather than trying to use a harness pulled from a donor vehicle. Unfortunatly I have to use a factory harness when I wire my buddy's motor in his XJ. Looks like I have a full day's worth of work on that one.

[NYWheeler]

Once you remove the computer harness there are very minimal wires left in the engine compartment. Its realy not that bad. Its also alot easier when you use an aftermarket fuel injection harness rather than trying to use a harness pulled from a donor vehicle. Unfortunatly I have to use a factory harness when I wire my buddy's motor in his XJ. Looks like I have a full day's worth of work on that one.

[Chris 88 YJ]

have you every looked in that 1.5" thick wire loom running across the top of the firewall .

Most of that is for the diag port and gets thrown out in a chevy engine conversion. Nothing behind the dash gets spliced, you just unplug the factory engine harness from the ECU and feed it back through the firewall. That splices to the vehicle harness under the hood. After that, you remove the engine harness from the firewall and cut everything but the battery positive wires coming from the battery, and a few ignition positive wires (1 for the coil and 2 for the alternator), a 12v in start wire for the starter, the water temp and oil pressure wires (1 each) and the fuse block ground. There is actually LESS wiring under my hood with the tuned port 350 than with the 4.2! It's so much neater now too. Wiring is the easy part, you still need supply that engine with 50 psi of fuel, and return it back to the tank but thats another thread.

if you guys want I can get some very detailed wiring pictures, and explain in detail what gets saved and where it goes.
http://memimage.cardomain.net/member_images/1/web/721000-721999/721405_19_full.jpg

If your serious about doing this right, get a conversion harness. I've done 2 TPI swaps and a TBI swap using factory harnesses, and this one using a Painless harness. It's easier than wiring up a head unit

[sentinal02]

Most of that is for the diag port and gets thrown out in a chevy engine conversion.

on a 4.2 yes, but the EFI 2.5 has a lot more sensors to deal with. trust me, i know, i rewired half of mine :lol: that's not to say they wouldn't get tossed in the swap, i was merely commenting on X's comment on there not being many wires in the jeep.

[XEON]

I would go a Chevy 350. But its going to suck all my gas in like 200 miles or less. I want somehting to do alright with mpg. Plus I dont need a v8. I dont need all that power. I drive slow and I wheel pretty mildly (thats for now :)).

Ahh I am dreaming... :lol:

[Chris 88 YJ]

Most of that is for the diag port and gets thrown out in a chevy engine conversion.

on a 4.2 yes, but the EFI 2.5 has a lot more sensors to deal with. trust me, i know, i rewired half of mine :lol: that's not to say they wouldn't get tossed in the swap, i was merely commenting on X's comment on there not being many wires in the jeep.

A 4.2 has a shitload of underhood wires. I had my 4.2 and my sisters 2.5 right next to each other the day I ripped my 4.2 out, and the 2.5 had just as much if not less wiring. I unloomed the entire underhood harness and removed most of it. ALL of the factory engine wiring goes in the trash.

[Chris 88 YJ]

I would go a Chevy 350. But its going to suck all my gas in like 200 miles or less. I want somehting to do alright with mpg. Plus I dont need a v8. I dont need all that power. I drive slow and I wheel pretty mildly (thats for now :)).

Ahh I am dreaming... :lol:

Just out of curiousity, what mileage are you getting now?

[XEON]

I would go a Chevy 350. But its going to suck all my gas in like 200 miles or less. I want somehting to do alright with mpg. Plus I dont need a v8. I dont need all that power. I drive slow and I wheel pretty mildly (thats for now :)).

Ahh I am dreaming... :lol:

Just out of curiousity, what mileage are you getting now?

I have not calculated it yet... My speedo is broke...

But I need more power. Just for the road basically its perfect for offroad.

[badzook]

I would go a Chevy 350. But its going to suck all my gas in like 200 miles or less. I want somehting to do alright with mpg. Plus I dont need a v8. I dont need all that power. I drive slow and I wheel pretty mildly (thats for now :)).

Ahh I am dreaming... :lol:

Did you know that a 4.3 Vortec V-6 puts out over 210 hp at the flywheel? It's nothing more than a 350 engine with 2 cylinders chopped off.

I have a 4.3 Vortec in another project of mine with a Large holley on it and it goes like hell.. It's really good on gas. Much better than a 350...

That little guy is plenty enough engine for your rig and you should get almost 20 mpg in your light Jeep.. and maybe you won't bust up your driveline if you're easy on it..

I've been tempted to slap that 4.3 into my Zook :roll: but it will bust the driveline like twigs :lol: .I'd have to swap to dana 44's to keep it alive and that's alot of work.....LOL

also, you'll have to deal with the emissions issue if doing a swap.

badzook

[rockdawg]

The 4.3 is a very popular swap and just about every junkyard has a few of them. The mileage should be better than a 4.0 jeep motor. (I'm lucky to get 15mpg when I'm nice to it)

[sentinal02]

I'd have to swap to dana 44's to keep it alive and that's alot of work.....LOL

and swapping frames isn't? :wink: as far as the jeep being lighter, gas milage has more to do with aerodynamics than it does vehicle weight. true it does play a part in it, but a lifted brick on wheels is still a lifted brick on wheels regardless of the engine. that's why the 4.0 and the MPI 2.5 as so close to each other in the milage dept on a wrangler. both hover right around 18 mpg on a well tuned engine. the 4.0 may have more power, but gas milage is still pretty much the same.

[badzook]

The 4.3 is a very popular swap and just about every junkyard has a few of them. The mileage should be better than a 4.0 jeep motor. (I'm lucky to get 15mpg when I'm nice to it)

yeah,

I'm just finding that out too.. I just put my XJ on the street last week and the Gas Mileage is awful.. The battery was disconnected for a few weeks so I'm hopeing the adaptive strategy will help out a bit, but I doubt it... Right now it's at 15 mpg ... Bummer... :( :( :(

My zook used to get 25 mpg so you can imagine the bite it took outta my wallet this week LOL :roll: :roll: :roll:

badzook

[badzook]

and swapping frames isn't? :wink: as far as the jeep being lighter, gas milage has more to do with aerodynamics than it does vehicle weight. true it does play a part in it, but a lifted brick on wheels is still a lifted brick on wheels regardless of the engine. that's why the 4.0 and the MPI 2.5 as so close to each other in the milage dept on a wrangler. both hover right around 18 mpg on a well tuned engine. the 4.0 may have more power, but gas milage is still pretty much the same.

Actually, now that you mention it.. We have a couple of company trucks that are Chevy S - 10's and the Vortec 4.3's get better gas mileage than the 2.2 gutless pos 4 cyl . That 4 banger screams it heart out trying to pull that truck around. While the 4.3 isn't even breaking a sweat..

The 2.2 gets about 16 mpg and the 4.3 is at around 21 last I checked...

Food for thought...:shock:

badzook