yj 2.5 to tj 4.0 swap questions - JeepForum.com

 
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post #1 of 9 Old 04-04-2012, 10:46 PM Thread Starter
rusty92yj
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1992 YJ Wrangler 
 
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yj 2.5 to tj 4.0 swap questions

Hey guys i just started doing my motor swap. I have a 92 yj with a 2.5 five speed and i got a complete swap from a 99 tj five speed. My motor brackets are being moved right now. My question is more geared to the wiring harness. Im under the impression i need to get a pcm and wiring harness from a 4.0 yj to convert the new motor back to obd1. Can i use my 2.5 harness and just add wires for the two new injectors? Or are they completely different? Also i read somewhere that i should change my flywheel to a yj 4.0. Is that necessary. Any help or links to more info would be really appreciated. Ive been doin alot of research but most swaps are between same years i havent found much info on tj motor into yjs thanks

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post #2 of 9 Old 04-08-2012, 07:10 PM Thread Starter
rusty92yj
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Anybody?
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post #3 of 9 Old 04-29-2012, 08:13 PM
colaman24
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You need the engine harness and PCM from the 99 engine, you could make your own harness. But better off going on eBay and finding one
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post #4 of 9 Old 04-29-2012, 10:21 PM
ratmonkey
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Convert to the yj 4.0 obdi set up. Unless you have the tool to add pins to the connector at the ecu, adding writes isn't much fun..of course, the wires would have to come from a 4.0 harness anyways, or extra 2.5 harness
Obdii would be better, but is an order of magnitude more work. I'd do it personally. Obdii is a much better system to work with.

'97 zj 5.2, some stuff, some other suff, and some things that even work sometimes.

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post #5 of 9 Old 05-11-2012, 12:39 PM
madyj90
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Rusty92 YJ, I was wondering how far did your motor mounts need to be moved for the swap?
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post #6 of 9 Old 05-30-2012, 06:46 PM
tequilamike
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Some things you will have problems with

Crank position sensor is in a different location.
Tranny mount holes have different diameter . Tj bolts are larger.
Clutch setup is different.
If you get creative you can use tj external slave with yj clutch master cylinder.
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post #7 of 9 Old 12-17-2012, 06:58 PM Thread Starter
rusty92yj
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Sorry i never got back to this site. Swap went well, pain in the butt but its done and she runs great. Had many issues and many hour of modding brackets to make everything work. Couldnt get my ignition to work with the swap, so installed a starter button and she is still running great.
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post #8 of 9 Old 12-17-2012, 07:03 PM Thread Starter
rusty92yj
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To mady j90, i dont know exactly how far the brackets were moved. I bolted mounts to engine, droped it in place, adjusted it where i thought it should be and drilled and screwed the brackets in place, pulled motor back out trailered the jeep to my friends house and had him weld them in place
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post #9 of 9 Old 12-17-2012, 07:10 PM Thread Starter
rusty92yj
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Also i swapped everything to obd1. It was worth it in the long run, but shoulda did the chevy 5.7 swap. Only reason i didnt is because i was told i woukd b changing the rear end cause of the torque. Shorty after the swap i exploded the rear anyway haha u live u learn
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