4.0 Conversion - JeepForum.com
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post #1 of 3 Old 02-23-2009, 02:08 PM Thread Starter
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1990 YJ Wrangler 
Join Date: Feb 2009
Location: OOB Maine
Posts: 38
4.0 Conversion

So i have a 1990 Wrangler and have been looking to get a rebuilt 4.2 but after doing alot of research i have decided to do a 4.0 swap. I found a rebuilt motor for sale that was currently installed on a 94 wrangler. I drove the four hours to check it out and it ran great, Paid a down payment on it and a week later was driving back to pick it up. I have done alot of research and made many phone calls and there are still some things i am not 100 percent sure about.

1. My jeep currently has an automatic transmission and the donor motor and wiring harness + ecu is out of the 94 with a manual. is this going to matter?

2. Was told by Bennie at hesco i need to get a speed sensor, do i need this?

3. Also found out that the transmission kick down setup was differnt on the newer jeep motor and i would have to buy a cable for it for
$68. There are not many writeups on here about this swap with a automatic transmission so any help would be great.

I think i have a pretty good grasp on the rest of the issues commonly brought up in all the writeups i have read (cps, flexplate/starter, inline fuel pump, throttle cable ect.) Any help/input with these issues or anything else would be very appreciated. THanks in advance.

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post #2 of 3 Old 02-23-2009, 06:54 PM Thread Starter
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1990 YJ Wrangler 
Join Date: Feb 2009
Location: OOB Maine
Posts: 38
So after more reading i am going to need a speed sensor adapter from hesco.
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post #3 of 3 Old 02-25-2009, 06:59 PM Thread Starter
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1990 YJ Wrangler 
Join Date: Feb 2009
Location: OOB Maine
Posts: 38
bump for some advice....
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