onlyinajeep726

I think I'm going to take a couple hours today and take a few different measurements on my XJ and MJ and get to the root of this predicament. If there's no appreciable difference, then my happy @$$ is going to be searching for a cheap wrecked '96 XJ with AX15. I just swapped in a 4.7 HO stroker into my XJ and did all the mods and adaptations to mate it to my Renix components. Fired up and runs like a champ, so I'm pretty confident I could do something similar to my MJ.

I know, I know... this topic has been beat to death so much that a well trained mortician can't bring it back from ruins. Anyway... I'm not sure why so many people have told me that swapping in a 4.0 into my '86 MJ will require massaging the firewall with a BFH. The only problem I've seen is 4.0 radiator fitment and the hood latch is going to have to be changed. From everything else I can tell, the length front to back and side to side are near identical to that of my '88 XJ with a 4.0. So, what gives? Can someone shed some more light on this for me? Perhaps I'm missing something? My goal is to snag an HO engine and AX15 (external slave) and mate it to a Renix 4.0 wire harness and ECU. Will that work also, assuming fitment isn't an issue?

What's your VIN? I'll create the link for you.

Sweet! Just checked all 4 of my vehicles, all with success. Just learned a few negative things about two of my rides though...

Not the original engine I see... Serpentine belt gave that away. *Edit: Unless, that's a trait of a 2.5L with A/C... then I would be wrong.

What's the tank size for a '86 long bed 4-banger, 4-speed?

:doh: It's okay man, $#!& happens. At least now you have a plethora of extra parts in the event those do actually crap out. ;)

It shouldn't matter what year your HO engine comes from because the casting for that bracket (in the first picture I showed) is the same for all 4.0L blocks. What will make a difference is what year that bracket comes from. If you are only able to find the Dorman bypass pulley for a '96, then go to the junkyard and find that bracket off of a '96. Although, I will say this much, that one in my picture that says it's from a '94 doesn't look any different than a '95, '96, and so on. When I dropped a stroker in my XJ recently, I was at the junkyard getting some parts and came across an OEM bypass pulley, and pulled the whole bracket and everything. Can't quite recall what year the donor XJ was, but I believe it was somewhere around a '94-'96.

The 4-banger doesn't have a stock electric fan.

Go to the junkyard and snag you one of these (the one on the left I mean, if you don't already have one coming with your HO). Then go to the parts store and get one of these... It's a Dorman A/C bypass or A/C delete pulley.

Temp sensor looks like this...

A 30x9.50 is almost the same size as a 235/75-15. A 235/75-15 is 28.9" diameter (that's one brand -- call it 29") and 9.3" in cross-section width. A 30x9.50-15 is 29.5" diameter and 9.5" in cross-section width. A 30x9.50 will not touch the flares if run on stock Jeep 15" rims. As commented above, there may (or may not) be slight rubbing of the tire shoulder on the lower control arms. If so -- either shim the steering stop, ir just live with it. A lift will NOT cure this. However, if you use 1-1/2" spacers, then you WILL rub the flares. I should have specified coil spacers, not wheel spacers. I was not aware of the control arm rubbing issues.

These symptoms you described sound really similar to the problem I'm having with my 2.5L... I still don't know what's going on with mine. :doh:

Maybe there was air in the fuel supply line after you changed the filter... :hmm: Glad it's good now. :yes:

http://www.dakota-truck.net/tirecalc/tirecalc.html A 30 x 9.5 x 15 is equivalent to a 241/79R15 (I know this tire size doesn't exist). I'd say you'd probably rub the flares, especially under load or at full turns. Consider some 1-1.5 inch spacers and shackles and you should be good.

Check that fuel rail pressure and see what it says. Maybe the new filter is faulty. It's rare, but it does happen. WIXs have pretty good QA, but it's possible that a bad filter gets out here and there. And I hope I didn't come off sounding like I was implying you're dumb in my previous post. No harm was meant...

I don't know who Ben is, but why not? lol I sent him a "Happy Birthday" via Google SMS.

Fuel filter on backwards by chance? I doubt it's on wrong, but just to air on the side of caution, did you double check? If that's the one variable that's changed, I don't know what else it could be. Stick the old filter back on and see if it still has these symptoms. Just my suggestion.

First time I've seen this video. That $#!& was tight! MJ FTW.

Anyone?

So, I'm not sure if this has been covered or done, but would it be fairly easy to rewire the turn signal/brake light combo such that the top segments of the tails light up exclusively as brake lights and the middle segments only light up when the turn signal/hazards are applied? I think this would be a cool idea and a way to stand out among other MJs. Also, I still plan to retain the dimmer parking light feature of both top and middle segments.

Because you rehashed a 3 year old thread, I found myself in the garage on this nice 85°F day masking and painting my tail lights... So thank you (no sarcasm intended). :yes: :wavey:

So moving that blue wire to the other side of the sweep will correct the backwards reading?

So, next question is, why the hell did they make the MJ and XJ MPFI fuel pumps different?? :doh: That's enough to drive someone crazy. They ought to be interchangeable... :fs1:

There's a little more to it than that... OP, what engine do you have in your Jeep? Also, what year and what engine was in the Jeep you took the full cluster from? The reason I ask is because if for instance you have a 2.5/4 banger and the full cluster came from a 4.0/6-cylinder Jeep, then you'll need to calibrate the tachometer. I know that a full cluster from a 1990 XJ/MJ is your best bet since there is a little potentiometer that can be adjusted to make the tachometer read correctly. I just did this swap about a month ago. If both Jeeps are 6-cylinders (either 4.0/I6 or 2.8/V6) then you're golden.