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Unread 04-07-2012, 07:34 AM   #361
Terry1961
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1990 YJ Wrangler 
 
Join Date: Apr 2012
Location: Mooreville, Ms
Posts: 8
can you tell me if you can switch the computer from a 91-95 to the earlier 90 4.0 without changing harness?

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Unread 04-07-2012, 07:58 AM   #362
Que89YJ
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1989 YJ Wrangler 
 
Join Date: Apr 2008
Location: Detroit, Michigan
Posts: 15,608
The 90 fuel injection was renix not Chrysler so no they are not a direct swap.
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Unread 04-07-2012, 08:18 AM   #363
Terry1961
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1990 YJ Wrangler 
 
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Location: Mooreville, Ms
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that means a harness change I am assuming
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Unread 04-07-2012, 08:43 AM   #364
Que89YJ
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1989 YJ Wrangler 
 
Join Date: Apr 2008
Location: Detroit, Michigan
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The 90 never came with the 4.0l or mpfi. Are you sure the setup is from a pre 91 xj. That is what you would have if you are correct.
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Unread 04-15-2012, 05:08 AM   #365
dirtyb
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1981 CJ8 
 
Join Date: Feb 2004
Posts: 42
Has this been verified?

Quote:
Originally Posted by remmons View Post
I cannot vouch for the GC, but on the XJ, all you have to do is twist the white and purple twisted pair together near the PCM. This will fool the PCM into thinking that the Security system is intact. This is what I had to do to my Basket Case, which is what I have been driving to work all this week.
I've done almost all of the mechanical parts of the MPI swap from a 1994 Grand Cherokee to my 1981 CJ-8 Scrambler. I'll start the wiring tomorrow, and honestly, I'm scared to death. Never did anything like that before.

So has anyone ever done a successful swap with a Grand Cherokee Laredo? Is bypassing the security system as simple as Remmons says? I understand that I have to also bypass the "Is it in park?" wires.

According to the VIN look up, it doesn't have an anti-theft
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Unread 04-15-2012, 10:09 AM   #366
JohnFM3
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1992 YJ Wrangler 
 
Join Date: Apr 2007
Location: Bonney Lake, Wa
Posts: 1,166
Quote:
Originally Posted by dirtyb View Post
I've done almost all of the mechanical parts of the MPI swap from a 1994 Grand Cherokee to my 1981 CJ-8 Scrambler. I'll start the wiring tomorrow, and honestly, I'm scared to death. Never did anything like that before.

So has anyone ever done a successful swap with a Grand Cherokee Laredo? Is bypassing the security system as simple as Remmons says? I understand that I have to also bypass the "Is it in park?" wires.

According to the VIN look up, it doesn't have an anti-theft
The only advice I can give is the obvious. Be careful of the wire placement. I did a MPFI on a 256 74 CJ. The head bolt studs got warmer than expected an fried the wiring harness. Which surprised me as my YJ was in the same spot with no issues.

Good Luck.
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97 XJ (Diablo) 4.0L H.O. w/AW4 4sp Auto Dana 30/Chry 8.75 2.5 inch Flowmaster Exhaust 4 inch Lift w/ 32inch tires & RS5000 Shocks
92 YJ (BOSS) 4.0L H.O. w/AX-15 5sp Manual, 231 TCase, Dana 30/8.8 (3.73) 2.5 inch Flowmaster R.E. 2 inch lift and 2 inch body lift for CJ clip
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Unread 04-16-2012, 11:25 AM   #367
remmons
Some assembly required.
2002 KJ Liberty 
 
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Location: Vernal, Utah
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Quote:
Originally Posted by dirtyb View Post
I've done almost all of the mechanical parts of the MPI swap from a 1994 Grand Cherokee to my 1981 CJ-8 Scrambler. I'll start the wiring tomorrow, and honestly, I'm scared to death. Never did anything like that before.

So has anyone ever done a successful swap with a Grand Cherokee Laredo? Is bypassing the security system as simple as Remmons says? I understand that I have to also bypass the "Is it in park?" wires.

According to the VIN look up, it doesn't have an anti-theft
When I was working on mine, I was to the point where I had most everything buttoned up. I had cranked on it many times with no results. I had gone through, checked, and rechecked EVERY wire that was related to ignition. It wasn't until I had discovered that the XJ that my PCM and wire harness came out of had a security feature. You will find on my link (in my signature), page 9, post #125 regarding the Security Feature. On my PCM (1993 XJ) the wires can be found on pin locations #26 and #46.
These two will be cut and spliced together.
http://www.jeepforum.com/forum/f12/i...l#post10338886 Post #146 (page 10) is where it all finally came together and the Jeep was able to run. http://www.jeepforum.com/forum/f12/i...l#post10382288 If you read through my thread you will see starting from page 6 through page 10 where I had tried everything to get the Jeep to run.

As you can see, I had went through heck to get this thing to run. So hang in there and keep trying, you will find the answer soon.
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Unread 04-16-2012, 12:19 PM   #368
Que89YJ
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1989 YJ Wrangler 
 
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Remmons..thats it.
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Unread 04-16-2012, 02:07 PM   #369
remmons
Some assembly required.
2002 KJ Liberty 
 
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Quote:
Originally Posted by Que89YJ View Post
Remmons..thats it.
Thanks Q! I have you and cevans87 to thank for my Jeep running. Maybe between all of us we can get these guys Jeeps running too!
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Unread 04-16-2012, 08:46 PM   #370
contdevelop
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2003 TJ Wrangler 
 
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Location: , Republic of Texas
Posts: 555
Great info! I plan to put the 4.0 head on my 258 but wanna keep the carburetor.
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Unread 04-22-2012, 12:51 PM   #371
cevans87
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1992 XJ Cherokee 
 
Join Date: Nov 2008
Location: , North Carolina
Posts: 411
Ok Since I have been running out of little things to do on the Jeep and I was getting a little antsy... I have noticed that I had a small oil leak coming from the oil filter adapter housing... the piece the oil filter screws into. Since none of the parts stores around had any of the 3 orings needed to "rebuild" the adapter, i opted to get rid of the adapter all together.

Here are the steps, read all of them first before starting:


1. The Adapter Housing either has a female hex or TORX, the TORX is T60 and more common. I have 96 XJ 4.0 Block and it was TORX, for pre 91 motors it is a 5/8" Bolt.


2. Used a TORX Allen Wrench set that I had bought for the torx bolts all over the Jeep a few months back, and it worked great with a piece of pipe I had laying around as a breaker bar.


3. Remove the Battery cable so you do not kill yourself before going any further.


4. Work from underneath, I have 33" tires and could work under the Jeep very easily.


5. Suggest engine cleaner/steam clean the entire passger side of engine on top and underneath first, and if the bolt torx hole is plugged with mud and oil like mine, use coat hanger and spray with WD40 or something, scrape it out.


6. Getting that T60 L Wrench aligned was one of hardest parts, did so from below. It took me minutes to get it aligned and drop in. Used screwdriver to pry the elbow part to seat as deep as possible, very close to a bolt on frame.


7. Have oil pan ready, it will leak.


7B. Leave the Oil Filter ON the Adaptor, easier that way, only one drip to deal with.


8. Using the T60 Torx Allen and my breaker bar it broke rather quickly and with minimal effort, unscrewing the bolt took a few minutes because it is a Torx and hard to line up.


9. It will start leaking, have a pan under it. Let it leak till slows.


10. The perfect tool to back out bolt more after no longer high torque is a T55 L wrench, remembered it grabbed, much much much easier to align. If you wrench from outside under (away from block) you can do it while its dripping without getting oily.


11. Once the oil has drained, removed the assembly. You will see a roll pin inside the block, this was so the adapter housing would not rotate on its own. Remove this with vise grips and keep it in case you want to get the oring kit and put the adapter housing back on later.


12. Get the old oring off the block and clean the surface with a lint free rag.


13. Looking at the adapter housing, you will see that the side the oil filter used to screw into will have a nut on it, it is 1". Unscrew this thread adapter and then screw it into the block.


14. Put a little oil on the new filters oring and put the new filter on.


Even though the new filter is smaller, i have not noticed any difference in psi. I still have 75PSI oil pressure.



Here are specs on oil filter to use or use one similar:


Brand Fram

Manufacturer's Part Number PH3614
Part Type Oil Filters
Product Line Fram Extra Guard Oil Filters
Summit Racing Part Number FRM-PH3614

Oil Filter Style Canister

Height (in) 3.360 in.
Outside Diameter (in) 3.000 in.
Filter Bypass Relief Valve Yes
Relief Valve Open (psi) 9-12 psi
Anti-Drainback Valve Yes
Smallest Particle Filtered 20 microns
Thread Size 3/4-16 in.
Gasket Outside Diameter (in) 2.781 in.
Gasket Inside Diameter (in) 2.484 in.
Gasket Thickness (in) 0.203 in.
dbfdbfgb.jpg  
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Unread 04-23-2012, 11:16 AM   #372
aggiejon
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1979 CJ7 
 
Join Date: Jan 2009
Location: Temple, TX
Posts: 585
Well I guess I'll try this again.

About to get my engine rebuild back together and start on my Junkyard MPFI. I just want to check and make sure I have my ducks in a row before I start.

Background:
1984 258 Engine
1979 Jeep CJ7 Rewired with Painless Wiring system
2001 Cherokee Head, intake, throttle body
1995 Cherokee Exhaust manifold, MAP sensor, starter
1995 Cherokee ECM, wiring harness,
2001 Cherokee TPS, O2 Sensor
1995 Cherokee Flywheel & CPS sensor
1984 Bellhousing for T-176 drilled for CPS mounting

I am fairly certain that my 2001 sensors will not work with my 1995 harness/ECM. I did retain the PDC in the harness. I have read many many many forum posts ad nauseum until my head has spun and trying to pick out the true jewels of the swap. Due to the information overload, I just want to confirm that my head is thinking right:

Sensors needed:
TPS
MAP
CPS
O2
VSS

Any others that I have missed? Do the sensors interchange (2001-1995? OBDI-OBDII)

Perhaps a reiteration on the Jeep CJ wires that go to the wires on the new harness to make it run. How many actual circuits are retained in relation to the 30 pounds of wiring that is in the trunk of that underhood harness
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Unread 04-23-2012, 02:04 PM   #373
Que89YJ
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1989 YJ Wrangler 
 
Join Date: Apr 2008
Location: Detroit, Michigan
Posts: 15,608
The VSS needsd to be the 91 YJ so you can drive the mechanical speedo and still get the ecu the speed input. I am not sure about the sensors but i would cross check the numbers before I spent any money on buying new ones. The O2 sensor should be good if I remember correctly.
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Unread 04-23-2012, 05:31 PM   #374
pete1991YJ
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1991 YJ Wrangler 
 
Join Date: Mar 2012
Location: Niagara Falls, NY
Posts: 1,635
Quote:
Originally Posted by aggiejon View Post
Well I guess I'll try this again.

Sensors needed:
TPS
MAP
CPS
O2
VSS

Any others that I have missed? Do the sensors interchange (2001-1995? OBDI-OBDII)
Since your 1995 ECU is OBD1, the sensors should also be for 1995 or older. Since you need the combo VSS from a 1991, I would just get all the sensors for a 1991, those will work with your 1995 ECU.

Switching between OBD1 and OBD2 is just too hairy IMO, so you are better to stick with OBD1 between 1991 -1995.
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Unread 04-23-2012, 06:49 PM   #375
Que89YJ
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1989 YJ Wrangler 
 
Join Date: Apr 2008
Location: Detroit, Michigan
Posts: 15,608
Some sensors do cross over like the O2 sensor. I would spend a couple minutes on a site like auto zone and cross refrence parts between the model years. If they don't cross refrence then you are only losing a couple minutes. If they do you could save yourself a couple hundred dollars.
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