OBDII 4.0 to 5.9L Swap Completed - JeepForum.com
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Go Back JeepForum.com > Models > Jeep Grand Cherokee & Commander Forums > ZJ Grand Cherokee Forum > OBDII 4.0 to 5.9L Swap Completed

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Unread 05-12-2008, 05:15 PM   #1
gunthagunth
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1997 ZJ 
 
Join Date: Oct 2005
Location: Pembroke, MA
Posts: 1,914
OBDII 4.0 to 5.9L Swap Completed

Been a while but I figured I would get on here and post up a quick writeup for anyone else trying to do this. I swapped the entire harness in from the bcm around the engine to the pcm and back into the fuse box. After pulling out the 4.0 harness I realized that they seem identical other than the extra sensor wires for coolant bottle and such, along with the electric fan. Also the evaporator core pressure switch has a different plug which can be spliced. I regasketed the entire motor along with paint and new accessories. Very much worth doing the swap. Plan on not having the vehicle for 2 weeks and many trips to the parts store, junkyard, and also needing a driveshaft resized. 3.73 gears seems perfect with 35's now with the power i have. Runs great on the highway and sits in overdrive. My mpg went up with this swap. I cannot wait to do another swap. I'll add to this if I figure new stuff to mention.

The parts list

5.9L Engine/Tranny/accessorys(you can use your stock ps pump and alternator(should upgrade alternator))
5.2/5.9 Air filter
V8 front coils
5.9 PCM and BCM(BCM will reflect donor vehicles mileage)
v8 y-pipe/manifolds(gaskets)/exhaust/sensors
v8 tranny lines
5.9/5.2 A/c lines
5.2/5.9 Engine info panel from above radiator
5.9L fan and heavy duty relays(preferably the stock ones) along with adjustable temp fan switch
Key fob setup to shut off alarm(I used the fob that came with my parts jeep along with the front passenger window switch panel to recieve the signal)
Engine Wiring Harness
5.2/5.9 Radiator/hoses
5.9/5.2 Throttle cable
5.9/5.2 vacuum/cable thingy on the passenger side that hooks to the throttle body
5.9 motor mounts/mounting brackets and hardware
Compression fittings and spare steel fuel line to adapt the 4.0 fuel line
Need to resize the rear driveshaft. I used the 5.9 one and cut some off the slip yoke(Ujoints are different4.0/5.9)

How to start

Have your A/C system drained from a shop
Pull The headerpanel and bumper off
Pull the hood off
Remove the condenser/radiator
Pull the old motor/tranny/exhaust/shafts


Swap the BCM from behind the headlamp switch up in the dash
Swap the PCM from the firewall
Install the motor mount brackets, notice you need to use the factory holes that are forward of where the 4.0 bolted up, these are probably full of mud and crap, use pb blaster and compressed air and a tap to clean the holes or just work a bolt in there with some pb blaster slowly.
Once they are bolted in you can lower the motor and bolt it into the brackets
Bolt on any accessories and wires, plug in the 2 engine harnesses, extend vacuums
cut and splice the fuel line to reach the rail
Bolt on the tranny and connect wires/dipstick
Attach shifter cable
Bolt on transfercase
raise tranny and install the tranny mount/crossmember
install cooler lines
install the ypipe/exhaust/o2 sensors
install the radiator/condenser/tranny cooler(optional)/headerpanel/and bumper
adjust the transfercase linkage
Check driveshaft length (with the d44 from the 5.9 I used the 5.9 driveshaft(UJoints matched, dealer only ujoints, at 80 bucks a pop i matched up some out of a 80's ford), with my lift i cut 3/4" off the slip yoke of the driveshaft to get it to fit. I will get a custom shaft)
Install/wire your electric taurus fan (5.9 fan wires the same)

Install the battery, check connections, add fluids, check (fuel, air, spark, and cooling) then cycle the key a few times slowly, crank, and pray. Mine didnt fire up becuase the neutral safety switch said i wasnt in park. After tinkering i got it to crank and fire. Took 5 days to replace everything i did (engine, tranny, wiring, rear axle, brakes, heater core, and evaporator core). I couldve had it done in 3 if i didnt remove the dash or rear axle.






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97 ZJ 5.9L 242/4.5" RE Coils/1.75" Spacers/Clayton arms/Addco's/RE brake lines/35x12.5 bfg muds/Currie steering/K&N/Claytons Front Drop tracbar/Dropped pitman/Bilstein 5125's/JKS BPE/JKS loop conversion/JKS Sliders/ZJilla rear bumper/Clayton front winch bumper/durango steering box/warn 9000i/Hambek Customs carbon fiber cowl hood #2of16/Hp30-8.8 4.56/ARB f+r
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Unread 05-12-2008, 05:22 PM   #2
Darthteddy
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Posts: 1,661
now make you a burnout video. haha.

GOod job on the swap. Whad you do with the old 4.0?
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93 Rubigrand - Sold... :'(
95 Grand Cherokee Limited - 5.2 Mall Crawler
55 Willy's M38a1 - 231v6, 33" Super Swampers, D44 Full Floater Rear, Locked Front and Rear, 5.38 Gears, Viair OBA, Bilsteen 5100 shocks, Dana 18, Turbo 350, S10 Power Steering, Tilt-wheel, Full Cage, Flat Fenders....
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Unread 05-12-2008, 05:23 PM   #3
greasefingers
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Location: Northern VA, USA, NJ
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Looks great! I love how the harmonic balancer/crank pulley is so large.
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Cheers Steve

94 Black Laredo 4-Liter with QuadraTrac (42RE trans & NP249 TC) 200,000 + miles purchased new

88 Cherokee 2-door with 5speed manual 139K miles(deceased) purchased new
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Unread 05-12-2008, 05:23 PM   #4
gunthagunth
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1997 ZJ 
 
Join Date: Oct 2005
Location: Pembroke, MA
Posts: 1,914
I have my old bfg's for the burnout:laugh. I have the 4.0 sitting in the basement for a stroker project that i will probably never get to.
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97 ZJ 5.9L 242/4.5" RE Coils/1.75" Spacers/Clayton arms/Addco's/RE brake lines/35x12.5 bfg muds/Currie steering/K&N/Claytons Front Drop tracbar/Dropped pitman/Bilstein 5125's/JKS BPE/JKS loop conversion/JKS Sliders/ZJilla rear bumper/Clayton front winch bumper/durango steering box/warn 9000i/Hambek Customs carbon fiber cowl hood #2of16/Hp30-8.8 4.56/ARB f+r
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Unread 05-12-2008, 05:25 PM   #5
QuadraTokn
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Posts: 5,047
Nice, I always wondered what it all required. Of course when I had my 4.0 ZJ i found the power/gas mileage combo pathetic and had to get a V8 WJ.

Did you need the 5.2/5.9 radiator?
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Unread 05-13-2008, 03:43 AM   #6
jeepheller98
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1998 ZJ 
 
Join Date: Mar 2008
Location: park ridge
Posts: 1,089
sweet dude, snazzy valve covers
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Unread 05-13-2008, 06:57 AM   #7
Katesdad
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I really like the valve covers also. One things for sure.... your no longer the 4.0 hero since you moved to the 5.9! LOL, I like the 5.9 wheels on there too!
After reading about the swap its clear a guy would be a fool to try this without a donor vehicle.
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Unread 05-13-2008, 07:42 AM   #8
JayJEEPguy
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2004 WJ 
 
Join Date: Nov 2003
Location: Bellingham, MA
Posts: 1,706
Glad to hear that you finally got it done!

So, with the complete swap, you should be able to pass the MA state inspection & emissions test, right?
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'99 GMC Suburban: Gas-guzzling people mover with 18" Z71 wheels
'04 WJ:Special Edition. V8, QTII, 2"BB, Bilsteins & 245/75/16" Goodyears
'02 WJ:4.7L, Selec-Trac. Totalled 9-12-07. Click to hearKolak 3" exhaust sound clip
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Unread 08-24-2009, 11:09 AM   #9
redhatman
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1998 ZJ 
 
Join Date: Jul 2007
Location: Minnesota
Posts: 2,388
Bringin the thread back... I am going to pick up a 5.2 Jeep tonight and will be using lots of parts off it to do this swap too!
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-Pat

I am now a dealer for Iron Rock Off Road
I offer the same great products you already know about,
the same low prices you have been seeing, and with
the same experienced customer support, but I can offer it nearly 24/7

"Project Dirty Princess"
5.9 ZJ 7" IRO, 35s, 8.8, hp30, locked, blah blah

"Project Grow A Set"

Quote:
Originally Posted by CMARJEEP View Post
Those tires look freakin awesome Redhat... took the ZJ up a notch in my book. Now you're at notch 2.
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Unread 08-25-2009, 06:58 AM   #10
BRIANC500
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1993 ZJ 
 
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Posts: 14
well done....
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Unread 11-03-2009, 09:45 PM   #11
redhatman
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1998 ZJ 
 
Join Date: Jul 2007
Location: Minnesota
Posts: 2,388
Hey man, I have started my v8 swap but decided on a 5.2. You say you replaced the BCM, is this necessary? I have the 1998 Limited, and my donor vehicle is a 1997 Laredo with vacuum doors and not many accessories. Can I just keep my current bcm?
__________________
-Pat

I am now a dealer for Iron Rock Off Road
I offer the same great products you already know about,
the same low prices you have been seeing, and with
the same experienced customer support, but I can offer it nearly 24/7

"Project Dirty Princess"
5.9 ZJ 7" IRO, 35s, 8.8, hp30, locked, blah blah

"Project Grow A Set"

Quote:
Originally Posted by CMARJEEP View Post
Those tires look freakin awesome Redhat... took the ZJ up a notch in my book. Now you're at notch 2.
redhatman is offline   Reply With Quote Quick reply to this message
Unread 09-05-2010, 06:05 PM   #12
gunthagunth
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1997 ZJ 
 
Join Date: Oct 2005
Location: Pembroke, MA
Posts: 1,914
its been a long time but for any future question of the bcm it was only swapped to show a accurate mileage on the new engine.
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97 ZJ 5.9L 242/4.5" RE Coils/1.75" Spacers/Clayton arms/Addco's/RE brake lines/35x12.5 bfg muds/Currie steering/K&N/Claytons Front Drop tracbar/Dropped pitman/Bilstein 5125's/JKS BPE/JKS loop conversion/JKS Sliders/ZJilla rear bumper/Clayton front winch bumper/durango steering box/warn 9000i/Hambek Customs carbon fiber cowl hood #2of16/Hp30-8.8 4.56/ARB f+r
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