||04-05-2008 11:08 AM
Engine swap wiring help needed 4.2 to XJ 4.0
Hey all, this is the second time I have done this swap (the first one was replacing a 2.5L with the XJ driveline). This time I did a couple things differently and I am not getting anywhere.
Engine, transmission, xfercase, wiring harness and ECU are out of a 87 XJ. I built a 4.5 stroker over 2 years ago and put it in my Cherokee. Cherokee ran fantastic before giving its guts to my YJ.
YJ had 4.2 that was hydrolocked when I purchased it. I pulled the driveline and installed all the XJ stuff from the front harness point of the firewall up. Now, 8 years ago when I did this swap I took the fuse box and interior wiring junction from the XJ and modified it to power the YJ. I figured this time it would be easier to just transfer over the appropriate wires on the engine side of the connector to match the YJ harness and keep the interior wiring intact. With my summit EFI inline fuel pump I get fuel at the rails. I have power at the ignition and from what I have tested everywhere under the hood that is supposed to. The engine just rotates but does not fire up. There is also no tach while cranking. I have tested for pulse from the injectors and nothing. I figured this was probably the typical Jeep CPS failure so I tested the ohms and it does not show up as open as I was told it should, it shows up at .188ohms and so does my new spare sensor so I figure this is close enough.
What am I missing guys? Nothing on the ECU harness has been messed with, with the exception of matching up the wiring at the firewall. It seems like I am lacking power somewhere or a trigger somewhere at the ECU to tell it to fire up.