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Author Topic: Wiring for engine conversion  (Read 2247 times)

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Offline canfourjeep

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Wiring for engine conversion
« on: November 25, 2008, 10:46:11 AM »
I have an engine from a 97 Astro Van and a 700R4 transmission.  I want to install this in a 95 YJ and am wondering if anyone has done this swap?
I checked with Painless and Howard wiring and they do not have a wiring harness for this swap.
Any help will be appreciated.
Thanks

Offline barmanjay

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Re: Wiring for engine conversion
« Reply #1 on: November 25, 2008, 11:39:47 AM »
You might have to get creative here

I do know there are many similarities that the YJ's have with GM

infact in 86 the cherokees came with the carb'ed GM 2.8 that was in the older s-10's

so maybe look at a wiring harness and ecu from an 88-93 blazer/jimmy with the 4.3 and get all the sensors aswell (the olders wiring harness may not plug into the newer sensors, so swap out with the older sensors)

Might have to splice into the dash harness to get all the guages to work

Hopefully this gives you somewhere to start.
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Offline boggincj7

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Re: Wiring for engine conversion
« Reply #2 on: November 25, 2008, 10:15:20 PM »
You should try Howellefi.com That is were a friend of mine got his harness when he swapped in a 4.3 from a 2001 blazer into a 70 CJ5. Said it was the best money he spent. It literally was plug in and start it up. Took him under 2 hours from install to it starting. It was expensive though. Here is the link   http://www.howellefi.com/shop/customer/home.php
« Last Edit: November 25, 2008, 10:20:30 PM by boggincj7 »
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Offline stroker sahara

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Re: Wiring for engine conversion
« Reply #3 on: November 25, 2008, 10:52:35 PM »
The swap shouldn't be that difficult as long as you are patient and have some mechanical and electrical knowledge. Try to get ahold of the wiring diagrams of both the YJ and the Astro van. I have a 1989 YJ that I swapped to a HO 6 cyl and it went very smoothly. I just had to re-pin the newer harness to match the old bulkhead and tap in the wiring to the guages. I had no experience with fuel injection until then.

As far as your electronics go, I believe that if you should only have to tap power from your ignition source to the computer. All of the other sensors will be wired in the harness. The only thing you may have trouble with is the electronic speedo, which may be a non issue. Rebuilding the harness to keep it tidy should be your biggest challenge.

PS, I will check my files because IIRC the harness I put in mine was from a 1995 YJ and I have the pinout diagrams from when I did my swap. I will let you know if I find them. I just noticed that you have posted before that yours is a 2.5L so the diagrams I have may differ slightly. You would just have to comare to be sure.
« Last Edit: November 25, 2008, 10:55:24 PM by stroker sahara »
If you want to run with the big dogs you have to be able to pee in the tall grass.


1989 YJ SOA, 36" SX, 4.6 Stroker...

Offline canfourjeep

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Re: Wiring for engine conversion
« Reply #4 on: November 26, 2008, 08:21:17 AM »
Thanks for the help.
I have wired a lot of classic cars and there is nothing to wiring.  I guess when someone says fuel injection the image of all those wires make you think it will not work. 
I actually have a 95 YJ with a 2.5 engine and 5 speed.  I am going to put a 98 frame and running gear under the body.  I have researched the frame dimensions and 4 mounts will have to be moved about 1 CM  to  change the body.    I also want an automatic and a little more power but not a V8 as a 4.3 will work good.  I have had a Toyota land cruser with a 454 as well as a CJ with a 460 that I used to race when I lived in Phoenix.  I do all my own work and this is just a project I want to do.  If you have Diagrams I would appreciate it.  I wire large industrial PLC controls so this can not be that hard. 
I spoke with a transmission shop and the guy said if I put a 88 model valve body in the 700R4 I would not need to worry about the Torque converter lock up.  Any help will be appreciated
Thanks

Offline stroker sahara

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Re: Wiring for engine conversion
« Reply #5 on: November 26, 2008, 08:54:21 PM »
I spoke with a transmission shop and the guy said if I put a 88 model valve body in the 700R4 I would not need to worry about the Torque converter lock up.  Any help will be appreciated
Thanks


All 700R4s have lock-up convertors. There is nothing to it to have it working, but at the same time, if you don't put the wiring in, it won't lock at all. I have a 1986 GMC with a 700R4 that has lock-up TQ, and also had an '84 with one. The tranny you have should be a 4L60E IIRC that is a newer version of the 700, but is computer controlled. I don't think the internals are interchangeable with the older trans.

Back to the fuel injection and what you said about all those wires. The original harness in my YJ for the carbed 4.2 had more wires than the injected harness.

As for wiring diagrams, I found mine last night and they are for a '95 YJ. I also have a buddy that pulls wrenches at GM, so I may be able to get a diagram of the Astro as well.
If you want to run with the big dogs you have to be able to pee in the tall grass.


1989 YJ SOA, 36" SX, 4.6 Stroker...

Offline canfourjeep

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Re: Wiring for engine conversion
« Reply #6 on: November 27, 2008, 05:24:07 AM »
The transmission is actually from a 90 Blazer which is a 700R4.  The astro had a 2 wheel drive. 
I am not sure about the transmission lockup the transmission guy told me about.  He said there are 4 plugs that need to be removed from the valve body to make it work.  I found lock up kits for 65 dollars  for the 700R4 and will probably go that way. 
Thanks for any drawings or help.