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2003 Jeep Wrangler TJ 300+HP 5.2 Magnum Build

19K views 29 replies 9 participants last post by  Vroutos 
#1 ·
Ok,

I've been told by a few of my buddies to do a write up for my build. Because everyone runs into different things during their builds I hope the things I ran into will help someone else with theirs.

I've been wrenching since before I could legally drive. I've built up a few vehicles from my 407whp 405wtq EVO 8, to my 05 Ram 2500 CTD with 1000tq, and pretty much every vehicle I've owned I've modified in some way to get more power, capability, handling what have you.

Please excuse the lack of pictures of the actual build my phone with the pictures got broken so I'm working on recovering them at a later time.

To start off I picked up a 5.2 Magnum out of a 98 Durango. I had already planned on rebuilding the engine because the engine was by itself, i never heard it run or anything and I planned on building it up anyways so do it right the first time and have a brand new engine to last for a while. I used an Engine Tech rebuild kit, the pistons, rods, crank, block and cam bearings were all in great shape so did a refresh kit with new rings, rod and main bearings. Dingleball hone to hone the cylinders.

I worked a lot with Backwoods Offroad and a big shout out to Evan over there for all the help he has given me. After he sees this write up he'll probably know exactly who I am lol.

Anyways I got their stage 1 cam for the engine, works with stock heads and springs, their budget headers which work and fit nicely, MSD ignition upgrade, their stock length hardened push rods, Radiator hose kit, some other stuff, and I had them do the wiring. Although it was expensive to have him do the wiring it was absolutely worth it.

Put a Comp Cams Performance Double Roller timing chain set, Mopar Performance Roller Lifters. I had to add a grade 8 washer measuring .050 +/- .003 underneath the rockers for the valves to close all the way with my set up.

Picked up a pair of new EQ heads from AA midwest in Las Vegas. Got a great deal on the heads from Kevin being a Veteran.

Put Harland Sharp 1.6 ratio non-adjustable roller rockers on it. From Kelly, he has an Ebay store and has the best prices around on them. I think that's what his name was.

Anyway the engine went together nicely outside of AA Midwest sending me the wrong heads from an LA block then had to get the right ones so that set me back a couple weeks.

I picked up an engine mount kit from Advanced Adapters at a Jeep/4wd show at the Puyallup fair for a discounted show special price and it worked out great.

Ok so now onto my build and how I did it. Once the engine was built and ready to go in I had already pulled the old motor out. I was keeping my Manual NV3550 transmission and transfercase, everything stayed in the stock location. I got a bellhousing from a 94 dakota off of Car-Part.com--Used Auto Parts Market I paid about $90 for it shipped from Florida.

Radiator is an aluminum Champion. 1987-2004 Jeep Wrangler YJ Chevy V8 Conv Champion 3 Row Core Alum Radiator
I got it off Ebay for $211.96 with free shipping. Great deal. I am using a Flex-o-lite 180 fan for the cooling and it doesn't have any problems.

I couldn't for the life of me find a dust cover for the transmission so I had to buy a dust cover from Mopar for a newer 2002-2008 Dodge truck part #52107753AC. I had to line it up and redrill a couple holes but it worked great. I replaced the stupid PITA bell housing torx bolts with regular grade 8 bolts. Works much better. The clutch and flywheel I used for it was from a 2001 dodge ram 5.2. I believe 11" Clutch it was a Sachs Clutch and a Luk flywheel. Since it was out of an automatic I got some ARP Flywheel bolts ARP part #240-2801 from Summit Racing. I had to get pressure plate bolts and got Mr. Gasket 910 Pressure Plate Bolt - Set of 6 from Amazon. Used Blue thread locker on the pressure plate and the flywheel bolts.

When it came to the motor mounts on my Jeep I cut the old ones off using a cutoff wheel on my grinder. After I did I realized that I have a portable band saw that would have made it much easier and much cleaner, that or my sawzaw, but didn't think of that until after the fact. My transmission, transfercase, and drive shafts all sit where they originally were.

The mounts were exactly 1/2" too narrow on each side from the frame so went and got some cold rolled steel 1" wide by 1/2" thick and my buddy did the welding for me, since I don't know how. He helped me line everything up, which took a while, some hammering in of the tub, some cutting of the tub with a grinder on the driver side, just the metal lip that comes out towards the front, I think it's part of the mounting plate for the Brake Booster. Anyways got that all banged out and fitted properly, then on the little part where I punch a little hole in the metal on passenger side with sledge hammer I filled it in with Hi-temp silicone, let it dry then repainted it silver.

Once we got everything lined up and tacked on to measure it all we welded everything in place.

For the ECU to save everyone the trouble I'm dealing with B&G Performance I'm getting beyond pissed with them, but I'll go into that later.
For the ECU check backwoods offroad in their FAQ section to see what type of communication you need whether it be PCI or CCD. I needed PCI. If you need the same, find one out of a 2002 Dodge Durango 5.9 R/T it can be reprogrammed to run the 5.2 and all your gauges will work nicely.

For the Exhaust I had to have custom Y-pipe made, there is nowhere online that I was able to find that had a pipe you could buy that would fit. I had Rob and Pro Exhaust in Auburn do my exhuast and he did an incredible job.

I already had a Magnaflow hi-flow cat, and bought a Flowmaster Hush Power 2 shorty. From the headers its 2.25" to where it joins at the Y, then goes up to 2.5" to the cat and all the way back. Rob made the tail pipe go up over all my suspension and everything.

I had the fuel sync done at the dealership. I later ended up getting a Snap-On MT 2500 off Ebay for $300 with cartridges. I had to get a K-13 Key to work with Dodge/Jeep/Chrysler products. I ended up having to adjust the Fuel Sync from 0 to between 4 and 6. Then reset all of the learning parameters.

I had a ground hooked up to the wrong place when I first tried to fire it up and the fuel pump wouldn't come on. Got the ground put in the right place and everything works and it fired right up the first time go.

That is pretty much everything, I know I've forgotten some odds and ends with little parts and I will add them in once I remember.


Now before I say this I'm not one to bash anyone or talk bad about someone because I'm unhappy or solve my problems whatever people do it for. I have legitimately had a terrible experience with them and am completely fed up.

With that said, now onto the horror story with B&G Performance that I'm still dealing with. I've done everything they have asked me to, I have been through everything on my engine and vehicle and verified that there is nothing mechanically wrong and nothing causing the issues. I called them to ask what ECU I should get and they said anything Dodge from 2003 V6 V8 it didn't matter, so I got one from and 03 Dakota 3.9L V6 is what I could find, that one came back and the tune was wrong, the gauges and everything worked except check engine light is on and throwing absolutely no codes at all, but is still on. With the tune it was over fueling like crazy to where it sucked through a quarter tank of fuel in 30 mins of idling. It is over fueling so much that it just washes the oil off the cylinder walls and can't seat the rings and build up compression. I called and told them the issues, and had to send the ECU back to them, keep in mind it costs me roughly $15 each time I have to ship USPS priority 2 day mail. The ECU cost me $90. They adjusted the tune and sent it back. Still had the problems with them lowering the fuel 12%. I called and talked to Dave the actual tuner there, he told me I needed an ECU out of a 98-2003 Ram 5.9. I went to the junkyard and found one out of a 99. Mailed it to them and had them load the same tune they put on the old ECU because I was under the impression the voltage regulator was bad for alternator in the 3.9 ecu and the check engine light issue. Anyways I got the ECU back and the tune was still over fueling, just not as bad and wanted to let learning curve see if it sorted itself out but I had no gauges. Sent the ECU back and they changed something else to try and get the gauges to work. Didn't work.

To cut to the end, I'm now awaiting my 3rd ECU from an 02 Durango. I called Evan and asked him what I needed as he has been doing these swaps for over 15 years. The fuel curve has been adjusted again and will hopefully be correct. Installed a wideband O2 to monitor and will work it out.

Everything in this swap has been pretty good and overall difficulty of the actual swap I would rate it at a 5 out of 10, just going through and getting everything done. The ECU tune is the biggest headache that I've been dealing with and eventually it will get sorted out.

Even with over fueling I have way more power and torque than the 4.0. Before it would struggle to accelerate on the freeway up to or from 60, on one of my test drives on the freeway it took off. I am excited to get the Jeep up and running exactly perfect and will enjoy a lot of times on the trail.

If you have any questions of how to do this swap just ask away.

I'll add some pictures of it now that it's done and a couple videos.













http://www.youtube.com/watch?v=75MuDEnT9lQ

http://www.youtube.com/watch?v=W0qUHUSwCNE
 
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#2 ·
UPDATE* New ECU is in and tune looking good. My faith has been restored in B&G Performance.

Fuel curve and driving/running parameters still being learned but its working much better now and should be all dialed I within the next couple weeks.

Also I remembered another detail about parts. The throttle cable is out of a 98 Durango, fits almost perfectly. I had to adjust mine since my motor is back a little further so I got come cable stops and a sweging tool from home depot. Ended up just running new cable and it works great. I also tightened spring on the throttle body and brought it down to a lower hook where the cruise control would hook up.
 
#3 ·
Time for an update, after half the break in period and watching everything I have found that the over fueling tune wiped out my bottom end of my motor. I had to buy a new short block.

I have a knock in the lower end of the motor from a rod bearing that got washed and likely the crank is gone too. I found a short block that will have new pistions, Moly Rings, new crank, cylinders bored out .030 so later on when I do my 390 stroker it will already have the machining done and make the change easier.

Just a word of caution for anyone who uses B&G Performance or A2Speed, its the same company. They have a disclaimer in their calibration form which literally lets them destroy your stuff, and they can't be held liable for it nor can you fight the credit card charges or get a refund. They have screwed Evan over recently too and he no longer will be doing business with them after 15 years of working with them.

If I had the choice and could get my money back I would never go with them. If you want to use them go for it, but there are other much better options out there and I recommend you don't give B&G Performance your business as they lack the integrity of a quality company and blamed me for everything that was going wrong even though it has come down to their crappy tune. I gave them all my cam specs and flow rate for my EQ heads, let them know exactly what mods I had. A good tuner could have gotten a runable tune in there and dialed it in from there. Granted I didn't add a wideband 02 till later, the tune should not have been over fueling that badly.

After a 30 mins of idling it sucked a 1/4 tank of gas. Everything mechanical on the engine was good up until that point. That was likely when my rings got wiped out.

Call Evan at Backwoods, he does these swaps for a living and has been doing them for years. WELL worth listening to what he has to say if you're looking into doing this swap.

Right now I'm adding a Poison Spyder hood louver to help get the excess heat out of the engine bay.

I'll update pictures once it's done. Doing a Rustoleum Spray can bedliner and its drying right now but it looks sweet and will look awesome on the Jeep once it's installed.
 
#5 ·
Bad ass. Im collecting parts for my 5.9 swap and keeping the ax15 behind it. I found the bellhousing in PA on car-part. The biggest challenge for me has been finding the manual ecu for a 5.9 although I think I may just buy an ecu and have it reflashed while adding a tune. Which flexlite fan is that? I was leaning towards an electric fan out of a wj . I may have missed it but what gears and tire size are you running?
 
#12 ·
Thanks man.

I would just have your ECU bench flashed. Although they have pissed me off, I would still say if you gonna go with a manual have B&G performance change the ECU from automatic to manual. Will help out in the long run and make it easier than trying to find a manual ecu. Are you going to be doing any mods to the motor or is it gonna be stock? If you have mods, be very specific with what you have to them and get a wideband 02 installed.

The flex-o-lite is the 180 black magic extreme.
https://www.amazon.com/gp/product/B000CNHFNA/ref=oh_aui_search_detailpage?ie=UTF8&psc=1

I used a Champion 3 row radiator 1987 2004 Jeep Wrangler YJ Chevy V8 Conv Champion 3 Row Core Alum Radiator | eBay
 
#18 ·
Right now my tune still needs to be dialed in and new short block broken in. That being said Evan at backwoods Offroad has a similar jeep to mine and H is getting around 16mpg in town I believe and about 20 on Hwy. For me the 4.0 I got 11-12 in town on a good day and maybe 13 on hwy if I was lucky.

It depends on what you have done to your Jeep. With 4.10 gears and 35's you should be getting nice MPG.
 
#22 ·
Actually on my 03 the charcoal canister is in passenger rear fender behind the wheel and the vacuum canister is passenger front behind the fender under hood next to the firewall. Its all there still.

i would reccomend for simplicity for everyone that if you have an 00 or older go with the 5.2 swap. If you have an 01 or newer do the 5.9. The conputer issue and tuning have been an absolute friggin nightmare. Mt build is correct, mechanically my build is perfect. Dave Kasper over at B&G has now fried my 6th ECU. Weird check engine light going on and the fueling goes all crazy. I had a good ecu it was working and functioning normally, then it came time to fine tune the tune and long story short he toasted another and keeps blaming "my build" saying something is wrong with it. There is nothing wrong with my build. Been in and out of everything, wiring mechanical, positioning, and nothing is wrong on my end except ecu.

Jeep runs, drives, and wheels just fine so I've been able to run it and I can say out on trails I should have done this a lot sooner!
 
#24 ·
Evan is a good dude. He uses B&G Chrysler for the tune also and has also had quite a few problems with them. I don't know if anyone has had as much trouble as me, but then again maybe someone has.

Evan does top notch work with wiring harness as well, although there is a kid there named Cody, who didn't want to honor the warranty of the harness and tried to charge me $200+ to fix a pre-existing condition with the harness that should have been caught first time but mistakes happen nobody is perfect. It ended up getting price reduced but Cody didn't have very pleasant customer service skills. Evan and Jay were always great, Jay not there anymore for whatever reason.

What year is your Jeep?
 
#28 ·
i bought a engine, wire harness & ecu out of a auto dodge ram. and i then found a dodge nv3500 in a salvage yard which will mate to my atlas II. i plan on sending the wire harness and ecu to backwoods to have them flash it. i just put a new cam shaft in the engine. went with a hughe's engine towing cam for more low end torque.
 
#29 ·
That's the way to do it. Nv3500 isn't rated for as much torque as Jeep NV3550 but it should be perfectly fine. Just as a reccomendation go with the luck clutch or upgraded. I hate the way the vlair clutch or whatever it is engaged. Too soft and it' rattles wshen out of gear and pedal not pressed.

If you want best trans get an AX-15 Termanator built to whatever power you want to. That will be what I do when my trans goes kaput.

I'll tell you you gonna LOVE that low end torque on the trails when fine is dialed in. Makes a huge difference over the 4.0. I can confidently power through pretty much anything I need to.
 
#30 ·
Hello,
Love your swap.
I have the same set up for almost 3 years with auto trans 46rh which I also love.
I am trying to make things easier and run my car with one ecu. Currently running the tj ecu for the gauges and the zj ecu for the motor.
The tj is 2003 pci and the donor is grand cherokee 1994.
Could you please tell me which ecu will work with my set up? Will I also need the whole fuel injection?
Thanks in advance
Tassos
 
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