Another wire harness thread

Another wire harness thread


Norman, ok
2012 JK Rubicon Unlimited, 6 speed factory
'78 CJ5 258 w/ 1 bbl, T150, Dana 20. 33's
'46 CJ2A L-head, T90, Dana 18
Ive got a 78 CJ5 with no engine but it did have a AMC 232 i6 with everything factory.

I bought a AMC 258 i6 / 4.2l with Howell fuel injection, hei distributer, And a powermaster alternator. All from an 85 CJ7 .

I've got the engine bolted on. But when it comes to the wiring I have no idea. I have the hynes and Clinton manual and I just can seem to follow them. The wires don't match up exactly.

My main thing is I don't know exactly what I'll need with the aftermarket parts. Will I still need the factory computer in addition to the Howell?

Can anyone tell me what I can get rid of on the harness?

my main problem is the starting at this point.
over the net, good luck
I think you will get a lot of grief before you are finished
in person with a professional looking at it, now your talking
my advice is to send it to a pro. with out the knowledge of being able to know what to keep and what not to, you are going be either having one of the longest threads in history, or give up half way.
Truly if someone here wants to take this on, they are a saint.
again, so that this does not end up being another half finished build on Craigs List, bring it to a pro.
I could not agree with Baja more. You just bought yourself a BarBQ'd elephant and now you have to decide how much you are going to be able to eat, the only way to eat an elephant is one bite at a time. You are not only going to need to learn about ignition and charging systems but also all about that fuel injection system. For a 20 year old kid, this is a really really major project. you did good just to get the engine in the frame. for one of us to try to help will be a lot like trying to explain what a banana tastes like over the phone, IMHO very nearly impossible.
On the other hand if you pull this off you will definitely be a jeep guy and others will seek you out for your advice. The information is out there, books and on line, but you are going to have to find it read it study it and understand it. owning a CJ is not easy, that's why every body doesn't have one.
If you do take this to a pro, the biggest problem I see is that he will own it but you will not. in other words if something goes south you will be right where you are right now only the diagrams in the book will be useless not just difficult to read. The pro is going to have to take "creative liberties" he will not be able to tell you about.

OK so this is a bit wordy because I am bored but the bottom line is this is a big job, if you do it you will truly own this Jeep but it is going to take a lot of time and a lot of study and a lot of thought. your basically designing your own system and duct tape splices and trial and error are going to be something to avoid. If your going to do it do it right. :cool:
Recently, I completely re-wired my CJ5 and would recommend doing the same if you've got time the the budget to do so. Keep in mind that I don't have fuel injection (no computer), no heater or A/C, and no radio which will all add to your difficulty. I did pre-wire it for a winch, AUX lights, and another AUX switch for any future needs. I had access to a bunch of high quality wiring so I decided not to use a pre-made wiring harness like EZwire or Painless. With the cost of copper wire these days, I'd recommend a wiring harness but I have no experience with either. I used a fuse block from West Marine and ran everything through that. Also, here's a shot of the switch panel I got from The12voltguy which is houses the headlights, Aux lights, wiper, washer, Aux switch, and Winch switches.

*These pix were taken prior to completion which is why they're cluttered.

Good luck and I'm happy to help if I can.
Hmm well I guess I really didnt peg it out to be that difficult as it's now sounding.

Would it not be possible to say buy a painless wiring harness for an 85 and then install the fuel injection harness?

Or would it really have to be from ground up custom?

Edit: just saw the post above.

I would really like to rewire the whole thing just to be as reliable as possible and this is a winter project for me and not a DD. I would love to build a harness myself but I'm just not sure I have the electrical background to do it.
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Hmm well I guess I really didnt peg it out to be that difficult as it's now sounding.

Would it not be possible to say buy a painless wiring harness for an 85 and then install the fuel injection harness?

Or would it really have to be from ground up custom?
Two things I don't have experience with are a painless wiring harness and fuel injection.
let me put it this way

first you have to decide what you do not need and eliminate that
then add the howell system
sound easy?
ok, go and eliminate all the computer stuff in the old system, and the computer, make sure you have an ignition systen that will work but can not be tested till you start the jeep and now the easy part, add the howell system so it works with all existing systems that can not be tested till the jeep runs

I could do it, would take me a few long weekends, but there is no way in hell I could explain to you how to do it over the net without spending hours and hours typing which I am not willing to do.

the good news is Nomad127 is willing to help you. He has stated he encourages you to do something he has never done, so get his help.

I am not trying to be rude, but FI is not a easy thing to do, are you going closed loop or open? Do you even know the difference? have you ever wired a vehicle before or did someone sell you on the idea? If so get them to show you how.

You see it is not just a matter of cutting here and slicing there, it is a matter of getting a computerized system to work with parts you may not even have anymore.

At this point, you need someone at the Jeep who knows how to do such, not someone trying to tell you from 500 miles away that has never even seen the basket case of old wiring you have, and yes, every jeep I have ever seen is a basket case of spliced wires.
Howell gave me installation instructions and a wiring diagram when I did my install. It was pretty straight forward and eliminated the old computer for the carburetor. When I wired my HEI I was able to get rid of the ignition module as well but I did add a relay to be sure that the distributor gets a good 12 volts to it.. This really cleaned up the engine compartment and got rid of a bunch of other SMOG related junk.
If I am remembering correctly I cut all of the wires going to the computer and then found the 12 volt supply line and used that to energize the relay that I added for the HEI distributor. The wiring for the computer and sensors was included in the installation instructions, but really easy to follow instructions.
If you need to contact Howell they wanted to know who purchased the EFI kit and then were very helpful.
PS I am very happy with the Howell EFI and my CRT HEI. The AMC 258 i6 / 4.2l starts easily and runs very strong so far in temps from 90 and down to 22 degrees so far and raining or snowing.
Thanks guys. I got it going. Just need fuel line for permanent fuel pump mounting and the clutch linkage.

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