1997 Jeep Wrangler R2.8 Cummins Installation Journal

BugoutJeep

TJ Addict
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Oct 31, 2018
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KY
I started a build thread on www.repowerowners.com and I'm just copying my own posts over here. In some cases, if I was asked questions or something of that nature, I will paraphrase, because I don't want to copy others' comments without their permission.

8/10/2018
It begins. Well kinda. The engine showed up, but I'm completely unorganized. I'll run up to Axis next week and pick up some goodies and start tearing into the Jeep next week too. New fuel tank is on order too.

Basic Build:

Mostly stock 1997 Jeep Wrangler with AX-15 and 4.0L Dana 30 front and Dana 35 Rear

Now or soon:
-Genright Enduro tank
-33" x 10.5" KM3s (currently 30x9.5 Buckshot Mudders and the OD is now 29")
-R2.8 Cummins
-Luk HD Clutch
-Intercooler, radiator, radiator bracket, Electric fan, engine adapter, motor mounts, hoses, misc mounts, sensor adapters, clocking ring, exhaust flange, a few other odds and ends - Axis Industries

Other Stuff Probably Soon
-Front Black Magic Brake Pads and Centric Premium Front Rotors
-Currie Sway Bar(s)
-Seats with cushion and less protruding metal
-Dakota Digital Adapter for Tach integration
-Fixing other broken components, I've been ignoring

One day/Until major destruction forces me
-Front and Rear axles, some sort of upgrade with selectable lockers
-Shocks
-Basic steering components
-skid plates
-Body cargo/protection mods

There's a lot of wants, but that's start.

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8/15/2018
Finally started tearing into the TJ. I've actually got a lot pictures and video of what I've been doing. Of course messing with the videos, kind of distracted me from labeling some stuff better. I'm going to take some vacation and hopefully get further along.

I still don't have my adapters and other install items, but I've been talking with Chris at Axis so that stuff should show up pretty quickly and I'm not ready for it anyway. My GenRight Enduro tank came in. I'm still waiting on my clutch and my steering gear box is leaking so now looks like a great time swap that out. I'm not sure how to do the video stuff, but I'll probably put it up on YouTube, if you're interested.

Btw there's a few things under the hood, that I'm not exactly sure what they do, so I'm going to get the manual out and see what I can get rid of to clean up in there.

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8/20/2018
Got a bit more done over the weekend. Found more stuff to address as well. Rear track bar bushing is shot and I will change to stainless steel brake lines. I've removed the fuel pump and I think I'm going to put new strainers on the housing. There's so much mud in there (not the tank, just everywhere under/in the Jeep). I've been cleaning and it's looking a bit better (photos are before any cleaning was complete). I found a couple rust spots, I'll touch up while I'm at it.

I'm waiting on parts to show up so I'm not getting any of the big stuff complete yet, but I've been getting the dash apart and cleaned up a bit and started fitting the pedal. Do you guys disassemble and bend the pedal arm or just make a new bracket?

I've found, what I believe is the correct wire on my ignition to make the Cummins fire with the key on.

I'm going to continue to clean tonight and remove my old catalytic converter. I think for the time being, I'm going to just go straight, maybe flex pipe to the existing muffler, but I am going to have to play with muffler/no muffler/new muffler to find what I want. I'm past the days of wanting a loud exhaust, but I do like a nice rumble and the turbo whistling a bit. I'm also not 100% sure my new fuel tank will work with the current exhaust. I got the GenRight Enduro, but in the instructions it mentions a sawzall to remove some of it, but never says to cut the exhaust.

Btw once I'm finished I'll post a bunch more pictures/video, but I've only taken a few with my cell phone. Of course right now it would just be me greased up and cleaning.

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8/27/2018
Took a few attempts, but it's in. I damaged my heater core tubing when I was removing the hoses because I'm an idiot. So I added a heater core replacement.

I've still got some stuff to change out that needed to be changed before the swap, but now a lot of stuff is easy to get to. I ordered the conversion kit for Axis, so hopefully the rest will be at my door this week for labor day weekend, if not, I'll get a head start on the exhaust, maybe sleep or something.

I spent a bit of time yesterday under the engine thinking about a skid plate for the future.

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8/28/2018
Does the flywheel housing have an inspection port that is normally left open? It's threaded there for what looks like a plug or something, but I haven't noticed any plugs.

*Received an answer that a pipe plug could be used, but wasn't needed
 
9/6/2018
*Responding to someone that swapped in the R2.8 Cummins in their JK.

That's awesome. How do you like it so far? What did you do with your gauges? Let me know what questions you have. I'm not finished yet. I'm still waiting on some parts and I have to get some farm stuff done by the end of September if the weather will allow it.
 
9/7/2018
*The JK owner commented on how much more torque the R2.8 Cummins has vs the 3.8 V6 and there's discussion of the Murphy gauge, boost gauge and EGT gauge and the forum member 3D printed a gauge pod for a dash mount. The forum member was ~90% finished, but was running into electrical problems.

I'd love to see photos. I've been thinking a lot about what I want to do for indicators. What type of electrical bugs are you having?
 
9/7/2018
*Photos of gauges are shared. The electrical problems include backup lights, tail lights, not working and working when specific doors are opened, etc.

Those do look good. I already have tail light problems before I started, so not much new for me. My turn signals have been busted so many times. Our woods are tight and seemingly always overgrown. When I get my TJ buttoned up mechanically for driving I'm just going to replace my wires going back to my tail lights and maybe front turn signals and headlights. My 97 TJ is fairly simple electrically from what I can tell. The funny thing and I'm not sure if you can tell in the photos, but I've got a Willy's CJ too and electrical problems have kept it from being reliable, but I haven't had a chance to completely rewire the Willy's. It seems like that kind of stuff wouldn't have any electrical problems, but at that age all the lines are dry rotted and since everything is metal and the lines ground out and over the years turn signals and conversions have added more wiring and very little of it was fused.
 
9/7/2018
Btw what transmission, gear ratio, tire size, mileage are you running? Have you done any towing yet? Does your stock tach work or did you go aftermarket?
 
9/13/2018
I've gotten a little bit done, but I haven't been able to do much for 2 weeks. I just put the fenders and grill on mainly for mock up and trying to get an idea on routing and how all the radiator/CAC/Fan goes in. My pedal position is set and it seems to clear the bracket for the oil filter, fuel filter, and grid heater mount pretty well, but I may need to slightly notch the throttle pedal bracket, but I think it's fine.

I need to finish fitting the CAC/radiator and grill and get that installed. I also need to find some good grounds on the block and ground to the tub and frame. Any advice is certainly appreciated if there's some good, no to very little mod areas to ground to. Some fuel lines and stuff should be in today so hopefully I'll get the new tank back in very soon and it might be close to a quick startup. I want to get the tank in before I mess with the exhaust either, just to make sure there's still clearance for it. I've been looking at the Jeep wiring harness stuff and it's more of a mess than I realized so back to work on another weakness of wiring and routing for me. But it should start without all that perfect and then I can focus on gauges and cleanliness.

I've been staring at the EGR lately and I'd really like that monstrosity gone. The firewall to the EGR is pretty close, which is a bit of a concern. I have trouble routing around it as well, but it's staying for at least a bit, but I may have to add some clearance to my firewall.

Any way, I can't wait to be able to get back to working on this full throttle. It's killing me to not spend every second of the day working on it, but I've got a lot of stuff at work and right now we have work to do on the farm. Maybe in about 2 weeks I'll have the farm stuff finished and won't have to go into work on the weekends any and I can focus on this project.

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9/13/2018
*Slight discussion on EGR and the aesthetics of them removed. Also it voids the warranty.

Yeah the warranty certainly keeps this on there and all the other work I need to finish first. Have you ever seen the QSF version of one of these engines? I was wondering if it had EGR, so maybe if you wanted it to really look clean, if you could get that thermostat housing too and I guess technically the intake or whatever on the other side and the exhaust manifold.
 
9/24/2018
Got my fuel pump delete, where I think I want it, but I didn't take a picture with my phone. I ended up doing a 1" body lift. It seems to make routing a bit easier and less cutting, but not necessary. I was actually mistakenly thinking my gas tank was mounted to the tub, which was a big plus for me to do this swap for more gas tank clearance. I was wrong, but I could make some mods to move the tank up, but that's not gonna happen, until maybe it's time for some Dana 35 work/swap.

I have 4x 33 x 10.5 on new 15" rims with 4.5" backspacing on the way. The KM3s and some Corbeau Moab reclining seats in black vinyl. I'm going to make custom brackets ie make mine work somehow and not lose functions.

The bleeder valves are locked up on my rear drums, so going to go ahead and do new brakes in the front and rear.

Got my fluids changed in my trans, diff, axles, and tcase, which was contaminated with water. In another notes of my mistakes. I had in my head my gear ratios were 3.73, but it's 3.07. We'll see how this is on the highway before I change any gearing.

I got some bare LEDs in to make indicators. I'm going to make a little circuit for the lights and mount a box somewhere. For the full wiring, I keep getting more nervous as there appears to be so much stuff to clean up and remove and wiring is an area I struggle.
 
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10/09/2018
I got more goodies in the mail and I had 1 day I could work on my Jeep.

I got the ECU installed. Tank is in place. Fuel lines are routed, but need to be cleaned up a bit. Intake/CAC tubing is still a work in progress, but pretty close. I'm starting to do some wiring. The brakes looked good so I only changed out the wheel cylinders and some springs.

By the way I got the conversion kit from Axis and everything is pretty easy for a build like this for someone with no experience swapping completely different engines. If you see something that looks really good, chances are I didn't make it. I'm still undecided on exhaust.

The more I think about it, the less I want to integrate redundant sensors and wiring into the build, so I'm very open to different gauges. I do want to try and find an app that will decipher the J1939 protocol, which I am supposed to be able to read from my BAFX OBD reader. Reading up on the protocol, I'm kind of disappointed in Cummins for using this protocol. I'm just starting to read up on it, but seems like there's a bunch of options without that choice.

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10/22/2018
*Quick discussion of J1939

Well it runs. Had an issue with some wiring on my part first and 2 wires I received were labelled wrong. Long story short the wiring harness I received had the starter and grid heater wire with the fusible link labelled backwards, so after a half second of starting the starter refused to engage and it took me a few hrs to come back around to testing the voltage again at the starter.

I was able to stretch the Cummins fusible wire from my battery terminal to the grid heater solenoid. Anyway I am very impressed by this engine. It is much quieter and less vibration than the 4.0 I just pulled out. I have no exhaust on there besides the DOC. It stinks less too. I think straight pipe shouldn't be an issue, but adding a muffler later is fairly trivial anyway. I can't wait to drive this thing. I'm getting giddy.

It really starts easily. I did prime the pump over 2 hundred times though and by the time I finished I couldn't get the pump handle screwed back in. I had to get a buddy over to help with figuring out the starter wiring and he had to do it for me.

Now that I verified operation, I'm going to really get heavy into the wiring and cleaning up loose ends and making brackets for new seats. I suspect I've got another 40+ hrs left before it's more or less ready and I'm sure there's going to be snags and continuous improvements.

Wednesday I'm going to grab a block heater from Cummins and hopefully I can figure out how to install it, due to space constraints. They sent me the diagram, so hopefully I won't screw it up.
 
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10/26/2018
I made a new harness that runs to the fuel level sensor, VSS, backup lights 4x4 indicator, etc. Once I hooked that up I have brake lights that work as well as they did before, which is that one still doesn't work at all, so I'll be pulling it apart.

The big stuff I'm missing are regular gauges but my Dakota Digital VFD 3 arrived with a couple modules. These will wait and I'll just use my phone or tablet for speed and everything else I can get from the Murphy gauge. I need to tap into the vacuum hose for the HVAC controls. The coolant overflow isn't here yet either. I'll make something work in the meantime. Routing wires will be a continuous improvement item. I have no exhaust yet noise or smell isn't an issue, but I'll have to straight pipe it sometime when I can get some time. I need to make adapter brackets for the new seats, but that'll wait as well. The cooling system needs bled and I need to wire up the fan. I have 1 more connector for this and it should be fine.

I'm going to button up some stuff and go to the farm this weekend and try to do some basic tests and take a break. Hopefully Tuesday I'll head up to Cummins and get the computer updated.

The Jeep will be a bit funny for a bit as a few items are going to be a bit ridiculous, ie I have my old exhaust wire tied to the frame right now and pulled the instrument cluster. I will probably have a Gatorade bottle or a used fire extinguisher as a catch can. I just don't see the point of addressing these items, until I can verify a bit more function on and off road.

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10/31/2018
I've been test driving the Jeep. I took it to the farm for a couple of days and took it to Cummins for the update. Wow. I wish the build had been cheaper and I wish I could have a few of them (small 4x4s with good mpg and off-road capability). Basically it drives like a 4x4 vehicle should drive, except it needs better brakes and I've got lots of rattles from old worn out parts. I don't have gauges, exhaust or my new seats installed yet, but it seems to be a dream to drive now on the highway and before it was a fist fight trying to maintain any speed above like 45 mph.

I like the new tune a lot. Before the tune it reminded me a bit of a race car or something. I have no experience with small diesels, but it was like I had some dead spots unless I was on the throttle hard. I'm really liking the 3.07s, but I may change just to have options for lockers and be able to run 5th gear a bit easier on some of the backroads.

Anyway a lot more to do to have it all finished, but I can use it for the time being this way without much issue.

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11/09/2018
Well I have added in Dakota gauges except fuel level isn't wired yet. I think I have a small leak or maybe spilled some fuel somehow. I've got the exhaust pretty close, but won't be able to get back to it until sometime next week.

I added a block heater. I've got LED headlights that should be here today, but I was supposed to leave a signature card on my door for them to drop off, but it was raining this morning and I forgot.

My 4Lo is way too fast. I think I'm going to swap out my Dana 35 for a Ford 8.8 that I'm going to buy mildly built from east coast gear and run 3.55s and ARB locker. That still puts me pretty fast in 4Lo. Looking at Atlas transfer case options and the 5:1 looks like my best bet, which should be close to what the newer TJ Rubicons/Willy's/a bit lower than my Dodge 2500 would crawl at. The 4 gear tcases add a bit too much of a price and the ratios don't seem as useful with my gearing, tire size, and driving style. I think I'll have to spend a bit more time in 2nd and 3rd gear though, but it seems like 1st 4Lo through 3rd in Lo would compliment 4Hi pretty well. The axle will occur first and I'll probably start getting serious about this in a year, which may give me time to overthink these options 100 times. And it'll probably be another year or 2 for the Atlas.

The axle really is something that concerns me a bit more than 4Lo at the moment. When this Jeep is fully built and out playing, it'll have a lot more weight and stress in the Dana 35 than it should probably see and I think a half ton axle should be plenty for what I'm trying to do with a sub half ton type vehicle. When I swap the axle I'd like to change the shocks and springs at the same time since at over 260k miles, it's time for a few parts.

So far my only fuel up was after about 220 miles 8.667 gallons. I'm probably going to top off today and now that I've got an odometer I'll try to get some more numbers. I'm going to be pulling a trailer and do in town stuff for some time so I'm sure the mileage will drop quite a bit, but nothing like it was before.
 
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11/14/2018
Bigwalker, I like the idea of the 241OR. The Atlas is probably overkill for what I'm going for.

The Jeep is running great. Did some towing over the weekend and for a TJ, all I can say is wow. I certainly had to shift a bit more with the trailer vs empty, but still it was pretty easy. Towing was easier on the highway than the TJ handled the highway previously with 29in tires and stock drivetrain. The trailer isn't super heavy, probably 1,500 lbs including the trailer. I noticed nothing while off-road (power wise) and highway I barely noticed a thing. I typically tow 65 mph or under and I would find myself over 70 in 5th often.

When getting on the highway while towing I noticed the thermostat opened or fan came on, looking at my temp gauges. The temps went to 190F and then dropped back to 178F pretty much continuously on the highway after that.

It was chilly tonight mid 20s F. I plugged in my block heater last night and the coolant temp was over 100F this morning so makes for some nice quick heat, if anyone is interested.
 
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11/14/2018
*Discussion of block heater

It's not necessary where I'm at, but simply a luxury item IMO. For like $40 from the dealer for the heater and cord, it's a small price vs the rest of the build.
 
1/31/2019
Just figured I'd do a quick update. It's been awhile. Mostly just cosmetic stuff.

I made a driver's seat bracket for the new seats and realized it put me up too high. I reluctantly bought the Corbeau seat bracket. It's ok but I prefer the OEM with OEM seat. The seats feel fine and I think look fine, but the brackets and seat height aren't ideal. The OEM seat bracket isn't easily modified to drop the seat either. I guess I just don't like the stock seat height in the Jeep. I like the function of the OEM brackets though and I haven't seen one aftermarket available that will sit lower. I think I'm just going to leave the passenger one all wrapped up and when funds are more plentiful, get the old seats reupholstered.

So far this is what I've come up with for the dash. I like it and it functions fine, but I don't have good access to the buttons on the Murphy Gauge. I just used a plug for a rotor and with a pen or pencil eraser, I can adjust the buttons. In the future once my accessories are added I'll be adding some gauges. I still have 1 wire to hook up for my gauge cluster to make it work properly. It won't dim currently and I haven't found the right wire to use. My wiring schematic isn't right for my dash and the only hot I found from the headlight switch also has 12V when I hit the brakes or turn signals. It's really not a big deal so I haven't really investigated this issue.

I'm still not sure what to put where the radio used to be. I guess more storage or something.

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