5.2L Magnum XJ engine swap

[CharlesS]

Here is a picture of the air filter I put on there. I'll likely change the filter to a 3" K+N if I keep this set up. Or if I can figure out a way to do a cone style I may go to that but for now this will work.

B

Been following your build over the past several months....
Very nice Bob......

 

[Bloose]

Look for a Grand Cherokee intake hat, it's very trim. It may fit under your hood. I think the Dakota runs a similar piece.

My TJ:

The Dakota hat appears to be exactly the same. It will not work for me unless I chop an even bigger hole in the hood. Thanks for the suggestion and picture though.

I think I'm going to keep what I have on there and just put a taller K&N filter in there. It's simple and it works. It's also high and pulling in cooler air than if I had the filter under the hood. Of course I am going to work on a scoop to cover it but it should still draw in cool air.

B

 

[Bloose]

Look for a Grand Cherokee intake hat, it's very trim. It may fit under your hood. I think the Dakota runs a similar piece.

My TJ:

P.S. now you have me thinking about a 5.2L for my wife's Wrangler. :eeks1:

B

 

[Bloose]

Been following your build over the past several months....
Very nice Bob......

Thanks Charles.

I really wish there would have been a nicer looking way to do the wiring though. Unless I do a completely hand made harness though what I have will have to do.

B

 

[Bloose]

Here's a quick update.

Before I started this engine swap my cruise control had quit working. It quit working when I swapped my worn through steering wheel with one from a '99. At the time I figured I messed up the clock spring. This swap of course did not fix the cruise. I did some searching yesterday to try and find the problem. I inadvertantly ran across an article that stated when sourcing switches from a junk yard to retro fit cruise into a non cruise Jeep you must get the switches from the same year Jeep. This is becase to facilitate using only two wires to read five switches each switch has a different resistance to ground. By sensing this resistence the computer knows which button was pressed. The problem is, for whatever reason, different year vehicles use different resistor values. Today I dug out the original buttons and put them into my jeep and presto. The CC is working.

That brings up two important points. First, the Dakota ECM is that compatable with the Jeep. In a previous post someone asked if the gauges worked. They were basically questioning if the CAN busses on these two vehicles were the same. The answer is yes. It dawned on me though the the Dakota was a 97 and my Jeep a 98. Apparently the switch resistance is the same between the two vehicles but not the '98 and '99 XJ'S.

The second point is that even the cruise is working with this swap! That is going to make the upcoming 30 hour trip out to Moab a little nicer.

I am going to wait on posting my overall impression of this swap until after the trip but up to this point it's looking pretty positive!

 

[kastein]

Nice!

Yes, cruise switches are year dependent.

95 and 96 are interchangeable, 97 and 98 are interchangeable. 99 through 01 are interchangeable. Crossing any of those year splits will result in strange behavior or it not working at all.

The one that really throws most people is the 98 to 99 change, because they used the same 8 digit numeric part number with only the revision letter code changed to distinguish between incompatible parts. That's very rare in the Chrysler numbering scheme (normally you can use a later revision code as a replacement with no issue, sometimes the reverse), though Dundy did find a counterexample, I forget what it was - something like a trans mount, motor mount, or diff thrust washer set where they did the same thing.

 

[CharlesS]

Bob and KAS,

Thanks for providing the CC information; it's good information for those that are trying to repair or retrofit their Jeep.

This is similar to the changes I found 9 years ago when swapping the gauge cluster from a '97 into my '98; I found out an interesting fact after examing the pin out schematics from both FSMs. The BUS wiring changed where the instrument cluster snaps in between '97 and '98. The major differences are the location of the grounding wires along with a few others.... You will have strange indications on the cluster..., but the gauges will work.

 

[kastein]

Really? That's funky as hell... I hope I haven't told anyone the opposite. I checked the parts catalog and the only difference (again) is the revision code... for example 5600 9727 vs 5600 9727AC. I'll have to remember that.

 

[Bloose]

Nice!

Yes, cruise switches are year dependent.

95 and 96 are interchangeable, 97 and 98 are interchangeable. 99 through 01 are interchangeable. Crossing any of those year splits will result in strange behavior or it not working at all.

The one that really throws most people is the 98 to 99 change, because they used the same 8 digit numeric part number with only the revision letter code changed to distinguish between incompatible parts. That's very rare in the Chrysler numbering scheme (normally you can use a later revision code as a replacement with no issue, sometimes the reverse), though Dundy did find a counterexample, I forget what it was - something like a trans mount, motor mount, or diff thrust washer set where they did the same thing.

That is just plain silly. I could see them making one revision along the way because of a problem, like the resistances being too close and with time the computer not recognizing them. I cannot see why they would make a change every other year or so. No too big a deal once you know but still, I see no really good reason for it.

Thanks for the info though.

B

 

[John D]

That's great the CC works too. The CC is the one thing I haven't been able to work through yet on my LS swap. The Chevy PCM uses +/- type inputs to control the CC while as you know the Chryco uses resistance.

It can be done on the LS swap and I plan to do it. Luckily for me Kastein understands it all and is going to make a switchbox for me...

 

[kastein]

That's great the CC works too. The CC is the one thing I haven't been able to work through yet on my LS swap. The Chevy PCM uses +/- type inputs to control the CC while as you know the Chryco uses resistance.

It can be done on the LS swap and I plan to do it. Luckily for me Kastein understands it all and is going to make a switchbox for me...

dunno about making it for you, but if you can get me schematics for the Chevy setup I can take a look and see if I can design it so you can build it.

 

[Bloose]

dunno about making it for you, but if you can get me schematics for the Chevy setup I can take a look and see if I can design it so you can build it.

Yes John, if it is just several inputs to the ECU making your own setup once someone tells you what to connect where should be fairly straight forward.

B

 

[Bloose]

Bob and KAS,

Thanks for providing the CC information; it's good information for those that are trying to repair or retrofit their Jeep.

This is similar to the changes I found 9 years ago when swapping the gauge cluster from a '97 into my '98; I found out an interesting fact after examing the pin out schematics from both FSMs. The BUS wiring changed where the instrument cluster snaps in between '97 and '98. The major differences are the location of the grounding wires along with a few others.... You will have strange indications on the cluster..., but the gauges will work.

I wonder if Kas's info should be put into the FAQ's somewhere? This type of thing could really F some one up.

B

 

[Bloose]

That's great the CC works too. The CC is the one thing I haven't been able to work through yet on my LS swap. The Chevy PCM uses +/- type inputs to control the CC while as you know the Chryco uses resistance.

It can be done on the LS swap and I plan to do it. Luckily for me Kastein understands it all and is going to make a switchbox for me...

I'm gunning to have the A/C working by next summer. It should just be a matter of making new A/C lines and charging the system. It also looks as though when I get time to make a bracket I may be able to run the York compressor in the same area it was on the 4.0L for OBA! For now though I'm going to run my QA2.

B

 

[John D]

dunno about making it for you, but if you can get me schematics for the Chevy setup I can take a look and see if I can design it so you can build it.

Thanks Ken, I will gather my notes and forward to you.

Yes John, if it is just several inputs to the ECU making your own setup once someone tells you what to connect where should be fairly straight forward.

It's always easy when someone tells you how to do it

 

[TerraWombat]

Is your fuel level gauge on the instrument cluster working properly? I assume you kept the stock XJ tank and fuel pump assembly. I think you used a Dakota PCM? I know that the resistance on the fuel level sender between the Dakota and XJ fuel pump assembly are different. Are you seeing that on the fuel level gauge?

 

[Bloose]

I could be wrong but I do not believe the fuel level sending unit goes to the ECM at all. You are correct that I used the Cherokee tank, sender, and pump. Other than the fuel lines the fuel system is exactly the way it came from the factory with the 4.0L. So my fuel gauge works the same as always.

HTH,
B

 

[Bloose]

Now that my trip to Moab is over I want to take some time to give my impression of this swap.

I believe it was John D who posted that once you swap in a V8 you'll wonder how you lived without it. Now that it's done, I'd say that's is 100% accurate. I love this motor! John I believe is running a 5.3L Chevy so the only thing his swap and my swap have in common is they're V8's.

Mentioned early on in this thread was that it wouldn't be worth all of the effort to do this swap because the 5.2's only put out 240HP. I disagreed then and I disagree even more so now. The HP is only part of the story, the increase in torque is another part. Below 3000 RPM this motor positively shines. Over that it is definitely more powerful than the 4.0L but the difference isn't night and day. Below 3000 it is. That means 90% of the time there is a huge difference and the rest of the time it's a nice difference.

In addition to power there are other advantages. One is the exhaust sound. I love it. The 4.0 sounded OK with the Dynomax bullet muffler I had on there but the V8 is simply music to my ears.

The throttle response off idle is very similar to the 4.0. This is nice on the trail because I didn't have to re-learn throttle control. As we all know when crawling HP isn't the key, most of the time it's finesse. If you had it with the 4.0 you'll still have it with the 5.2.

The drive to Moab was so much nicer this year than last. With my Cherokee weighing in at 5000 lbs with no gear in it and 5400 lbs loaded for the trip the 4.0L just couldn't maintain speed in OD. I had to constantly drop it into 3 with any head wind or the smallest incline. When going through the mountains it couldn't keep speed even in 3 with the 4.0. I had to drop down to 2nd and rev it to 4500 all the way up or let my speed fall to about 40 MPH. With the 5.2L it cruised nearly the entire trip in OD and maintained speed without a problem. Once I got to the mountains it couldn't keep speed in OD but had no problem in drive (3). The RPM was a much less stressful 3300 RPM. The fuel mileage is down about 1 MPG from the 4.0. Well worth it in my book.

You add it all together, great sound, nearly the same MPG, excellent power exactly where needed and I can honestly say this is the best mod I have ever done. It'd be very hard for me to say whether or not this is a better way to go than a stroker because I've never had a stroker. From talking to others who went the stroker route I've heard good and bad. For me, I'm very glad I went this route. If you're considering going this route remember this is a ton of work and very time consuming. If you know you can see it through I say go for it and don't look back. If your time, or ability is limited a stroker may be the better way to go.

B

 

[TerraWombat]

I could be wrong but I do not believe the fuel level sending unit goes to the ECM at all. You are correct that I used the Cherokee tank, sender, and pump. Other than the fuel lines the fuel system is exactly the way it came from the factory with the 4.0L. So my fuel gauge works the same as always.

HTH,
B

The fuel level sensor signal goes to pin 26 on the C3 (gray) plug on the PCM and then is transmitted over the CCD Bus network that the instrument cluster reads from.

So the fact that you have a Dodge Dakota PCM reading the fuel level correctly from an XJ pump module is encouraging news for me - although I have a ZJ PCM reading a Dodge Dakota fuel pump module.

Glad to hear that you had fun out in Moab - makes me want to get back into my 5.9L MJ, but I need to buy a house first

 

[kastein]

On a 98 the fuel sender definitely goes through the ecu, it's like that on all 97+ and possibly 96s as well. 95s and down it goes direct to the gauge.