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Old 07-14-2014, 10:16 PM   #1
Join Date: Apr 2014
Posts: 3
Engine swap help needed

I am jut finishing an engine swap from a 2.5l to a 4.0l and I have no spark or fuel.
my jeep is a 90 YJ 2.5l and the donar was a 94 yj with a 4.0l. Both standard. I swapped the engine, tranny, transfer case, rad, shroud etc.

I kept the main wiring hardness and the fuse box from the 2.5l but I took the EMU and the engine harness from the 4.0l (just plugged into the harness on the firewall.

replaced the distributer, rotor and pickup as well as crank sensor and still nothing. Turns over great.

I am sure it is something different in the wiring but I have no idea what.

Any help from someone who has done this before would be appreciated

stevemac is offline   Quote Quick Reply
Old 07-15-2014, 06:03 PM   #2
Join Date: Jul 2012
Posts: 207
I do not have the 90 or 94 wiring diagrams but I checked the 92 version of the 2.5 versus the 4.0 and they match up pretty well. My guess is that you will need to get both wiring diagrams and start comparing.

WICruiser is offline   Quote Quick Reply
Old 07-16-2014, 02:03 AM   #3
Join Date: Jan 2013
Location: Adair Co. KY
Posts: 429
With a 90 model being tbi vs a 92 thats multiport I would think there would be a great deal of differences. I've read that yes on a multi port 2.5 going to a multi port 4.0 is a simple swap just added two injector wires, swap computers and such.

I too wish I could help more but don't have the fsm's either. Maybe one of the guys that do will chime in. Once you have the pin outs for both it should make it a lot simpler.
My 305 swap http://www.wranglerforum.com/f8/89-y...ad-256560.html
Debating a Chevy v8 swap? read this thread
kywaterman is offline   Quote Quick Reply

2.5l to 4.0l , engine swap

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