**HELP**4.0 XJ swap into 91 YJ..NO START

Well, here is my problem. I have a 93 XJ 4.0.AW4 in my 91YJ now. Wired the bulkhead connectors and the starter cranks but the motor won't run. I swapped out the fuel pump (got a new one for a 91 YJ 4.0 so it would fit into my fuel pump harness) thinking that was it but it still will only run VERY ROUGH for about 5 seconds and cut out. I am going crazy here. I used the entier harness out of the 93XJ so there is no problem there. I have the fuel pump power wire right to the batters (Thinking the relay may be bad)

With the 93 4.0, it has the feed and return fuel line on the fuel rail. There shoudn't be "pressure" in the rail once the motor is off right? It has the return line so how could it be pressureized? Or should it and I have a bigger problem?

Since it won't stay running, is it:
The ASD relay giving me grief
Computer not getting a signal so stay running
I have a wire crossed in my bulkhead diagram

THe starter kicks the motor off fine, it just won't run..

Any help is VERY appreciated..Thank you..Joe:wave:

Contact Copper204, he is the expert on this...

Good luck!

THANK YOU!!! I will contact him...Much appreciated!!

Yes you will have residule pressure in the rail. Not enough to matter. the pressure and release there of is controlled b y the vacuum actuated fuel pressure regulator at the end of the rail. Curious are you sure you used the right lines? I have made that mistake in the past...lol.. I goobered it once on a throttle body jeep . I am still thinking your gonna find a bad ground. You can test proper connections by checking with a trouble light at the diagnostic port with key on. When you test the port you incidentaly energize the fuel pump on one test. kinda funny but it is the way it works. i am afraid tho' you will find out the XJ doinor was probably a SKIM Cherokee. KJ can tell you all about the fun of that when trying to load a dead battery on a SKIM cherokee. KJ kinda sounds familiar eh, what he is describing, was exactly what the Cherokee did when the guy tried to come pick it up a couple of weekednds ago? JOEV I have another computer you can try or borrow one locally to test if yours was from a SKIM car. or call and ask all the questions you can think of: Hal 209-743-3699 :viking: