Originally Posted by
jdarg
I did this in my 94 YJ three years ago. Put a new 260HP 350 crate motor w/ TBI donated from an 88 Camaro in it.
The stock YJ fuel pump, regardless of whether it was 2.5 or 4.0L, is just fine for the TBI.
The engine harness is pretty much "stand alone" on a 94, so there's no need to even touch the underhood fuse box. Everything you need to splice to is in that engine harness. When all was said and done I literally only had to splice one wire that wasn't in the engine harness and everything merged perfectly with remnants of the YJ engine harness for the cab gauges, etc. I used an 88 Camaro engine harness as the donor. All my gauges as stock and work perfectly w/ the 350, including the tach which I modded with a resistor to make it work w/ v8 vs. i4. Stock Jeep VSS feeds both the dash and ECU. Change the PPM from 2000 to 8000 in the bin. Even though the Jeep VSS was 8v, its fine just feeding it 5v from the TBI ECU and the stock speedo still works fine. Its more than three wires if you want everything 100% functional and stock appearing, but yeah, probably just 3 wires will make it at least drive.
YJs seem to be built for this swap. You really can't even tell it isn't stock. Even the bracket that holds the fan and fuel relays fit into existing holes on the fender with no mods. Just crazy. The splices are extremely minimal because its all in that one engine harness except for one more wire. I have 4.88 gears and maybe 220-240HP and this thing pulls hard through 4000RPM even with the heavy 34" swamper tires I have on it. Totally glad I didn't just go with a 4.0L. Running the AX15 and 231 - the clutch was an absolute nightmare to get right but it finally is right, using stock hydraulics. Third gen Camaro headers fit great although the front shaft gets into the exhaust just ever so slightly. It self-clearanced though so its fine now. I'm SOA if that matters. If you aren't it probably won't enough for that to happen.
You will want some way to tune the computer, I run EBL in mine.
If you have any specific questions about the swap please let me know.
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