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Discussion Starter #1
Well, I just picked up the new motor/tranny/transfercase for my YJ.
It is a 4.0/ax-15/231 combo out of a late 90's cherokee. I am doing this swap because the whole combo was, well, I did not have to put any green down. Free in other words.

My questions are this:

How can I find out exactly what year the motor is? Where are the casting numbers or whatever? I am told that Jeep changed teh wire coding from year to year, and that somwhere around 97 they went to OBDII computers.

Are there any bolt in engine mounts (as opposed to weld in, I can weld, just do not want to chance that).

If this is an OBDII motor, what do I need to do for a fuel pump? I have heard that I can just disconnect my intank pump I have now (basically cut the wires) and just put an inline pump in that provides more pressure. Is that possible, or do I need to do a WHOLE bunch of fab to get a newer pump into my tank or whatever...?

I have read a few write ups, but I have found conflicting info on the pumps, and I dont want to piss away good benjamins...

Thank you all for your support and advice.
 

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Seems to me like you could just get the tank, or pump from a 4.0L YJ, couldnt ya?
 

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I guess that the newer ones have a higher pressure fuel pump, and that started in like 98 or something. So just trying to gather as much info on this before I jumo in and it gets ugly...
 

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Your engine should have a barcode decal on the valvecover. Take all that info to your friendly Jeep dealer and you should come up with year and model application. That will get you started. Research that other board CJ----- as well as here on 4.0 conversions and you will get schooled on the subject. Look at your fuel rail--does it have a line in and a line out or just a line in. If it is a single line application it is OBDII. Do you have to pass emmission testing? As far as motormounts , it should drop in right on your exsisting mounts. If you have the 258 YJ you will use the mounts off your old engine and one hole on the new motor is tapped metric so watch out
A lot of the conversions used a Ford Van fuel pump that mounts to the frame rail of of a late model fuel injected 6 cyl van--the infor is in the posts. If you are OBDII you will need 50+ PSI at the fuel rail
 

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I don't know much here about this application, but GirlJeeper is correct about fuel pressure being 50+. I just want to say that it's very critical that you set it excatly where it should be within one pound or so. If you regulate it, give it two more pounds.
 
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