A little question

My xj is a '90 model well atleast that's what the title says. When I first got it I went to do an oil change only to find out I had the wrong filter. By the book fram for example (and no I do not use fram filters) says a '90 takes a ph3985 I believe, but mine takes the '91+ ph16 filter. I'm really just confused by this. It seems that everything I get for the engine has to be looked up as a '91 model. Did they put '91 model engines in some '90 models or something. That I know of it hasn't had a engine transplant, but I did get the truck with 189k miles on it so that could be a possibility. Is there anything i could look for like casting numbers or something that would tell me exactly what this engine is. I like my truck but I've come to figure that in this year model it's like pulling teeth trying to figure anything out about it. When you combine the engine with renix and an aw4 tranny it can be just mind boggling. Any help would be appreciated and I do mean any.

What is the 10th digit in your vehicle indentification number? L is 90. M is 91.
Why didn't the first filter fit? Too loose on the threads or wouldn't start on the threads?
The older filters were 20mm threads and the later models were 3/4" pipe thread.
When they made the change in oil filter application, I had customers at the dealership put the older filters on their newer Jeeps only to have them come unscrewed down the road.

I think it was too loose, but honestly it has bee about a year and I can't remember. I think It still has the warning label on the firewall still, I'll look at it later and see if it says metric or sae. I do know I've ran the newer filter for the last year with no leaks at the filter or problems with the filter loosening.

Ok double checked the VIN and it says L, so title is correct. Even the VIN on the vent window says L. The firewall sticker says M20. So everything but the engine itself says it should be the old filter. Considering that 20mm is almost exactly 1mm bigger than 3/4" I wouldn't think the new style filter would fit on an old style sending unit without messing it up, and the new style filter goes on without a problem. The filter mounts almost straight up just angled slightly towards the fender. I know the mounting changed a few times if that helps.

After a bit of digging around google and a factory parts manual. I've managed to find a block serial# of 006mx29 and a block casting # of 53008405. According to this post (http://www.jeepforum.com/forum/f11/4-0l-serial-number-location-995174/) my casting number corresponds to a '91-'95. So I'm assuming I'm looking at an engine swap. i now have no clue how many miles are on this engine. Did find a the original warranty book that has the correct vin listed and it says that the truck was originally sold to a local zoo. I'm going to dig a little next week and see if I can come up with some service records.

Good to know. I don't think the SAE filter would thread on to the metric fitting.

My '92 has the warning sticker on the firewall, suggesting that the size had been recently changed. Another interesting little nugget may be to check the build date on the sticker on the driver's door. As they come to the end of a model year, the newer stuff started to be incorporated into the older model.Your '90 may in fact have some '91 bits in it if it were a very late '90. You're near the Renix/OBD conversion. And since the body didn't change much through the run, the model year offerings were often blurred. Our '96 Classic has '97 wiper arms, and some under hood stuff is different than our '96 Country.

A lot of people have converted the metric OFA to SAE, by either changing the complete OFA--the hard way--or by simply installing Chryco part number 53007563AB, about $8 at the dealer.

Everything you need to know:
http://www.madxj.com/MADXJ/technical/technicalfiles/ARoilFilterConversion/OilFilterConversion.htm

joe_peters said:

A lot of people have converted the metric OFA to SAE, by either changing the complete OFA--the hard way--or by simply installing Chryco part number 53007563AB, about $8 at the dealer.

Everything you need to know:
http://www.madxj.com/MADXJ/technical/technicalfiles/ARoilFilterConversion/OilFilterConversion.htm

Click to expand...

Many Renix owners, like me swapped the pipe nipple and use the newer, larger oil filter.

heyhar said:

My '92 has the warning sticker on the firewall, suggesting that the size had been recently changed. Another interesting little nugget may be to check the build date on the sticker on the driver's door. As they come to the end of a model year, the newer stuff started to be incorporated into the older model.Your '90 may in fact have some '91 bits in it if it were a very late '90. You're near the Renix/OBD conversion. And since the body didn't change much through the run, the model year offerings were often blurred. Our '96 Classic has '97 wiper arms, and some under hood stuff is different than our '96 Country.

Click to expand...

Door sticker is no good on this truck. I noticed when I got it that the driver side doors look a little off colored in florescent light. I'm pretty sure someone painted those doors at some point and in the process removed the sticker. Originally I thought the doors were replaced, but the vin etched in the vent window matches the dash vin.

joe_peters said:

A lot of people have converted the metric OFA to SAE, by either changing the complete OFA--the hard way--or by simply installing Chryco part number 53007563AB, about $8 at the dealer.

Everything you need to know:
http://www.madxj.com/MADXJ/technical/technicalfiles/ARoilFilterConversion/OilFilterConversion.htm

Click to expand...

Pretty sure this hasn't been done. Mine mounts with the threaded end of the oil filter facing down. Almost completely vertical and tilted just slightly towards the fender.

What I know so far is that the vin says '90. The firewall sticker says it takes a 19mmx1.5 thread filter. The engine casting # says it's a '91-'95 and it actually takes a 3/4" thread filter. It is a renix system with distributor/coil setup with aluminum valve cover.

Can anyone give me a straight answer as to when the xj's switched to a OBD system, because I can't seem to find a straight answer on that.

I much prefer working on my little S10. It's got 327/th400 combo and the only computer on it is the radio. The whole reason I bought the jeep was for something to drive everyday during and after I swapped the motors out in the S10. Sure it's got 400 horses but it's only got 3 gears and about 12 mpg.

Jeep 4.0 engine management:

87-90--Renix.
91-95--OBDI
96-01--OBDII

joe_peters said:

Jeep 4.0 engine management:

87-90--Renix.
91-95--OBDI
96-01--OBDII

Click to expand...

Given that the block is a 91-95 which would have been OBDI, and the truck has a renix setup. I'm assuming I would be possible to swap everything from an OBDI era block to make it a Renix system.

In the mean time I'm trying to work on a diagnosis for my tranny. If anyone wants to help with that I'll enlighten you with the details. As for now I'm working through testing all the electricals with the help of this page. http://www.transonline.com/transdigest/magazines/1997-10/Shift Pointers/index.html

???

Your XJ is a 90, it runs, ergo the 91-95 block has already been set up as a Renix and nothing more needs to be done.

As to the OFA, there are a number of things that can/could/might have been done. Your OFA is vertical. That would be correct for Renix AND early OBDI engines. An early OFA can have the nipple replaced and remain vertical but now use SAE filters--part number I posted above. The ONLY thing that determines the position of the filter in relation to the block is a little roll pin in the OFA. This can be removed, a new hole drilled, and then the OFA can point in any direction you can make fit--you can do this with the early vertical or later horizontal OFAs.

joe_peters said:

???

Your XJ is a 90, it runs, ergo the 91-95 block has already been set up as a Renix and nothing more needs to be done.

As to the OFA, there are a number of things that can/could/might have been done. Your OFA is vertical. That would be correct for Renix AND early OBDI engines. An early OFA can have the nipple replaced and remain vertical but now use SAE filters--part number I posted above. The ONLY thing that determines the position of the filter in relation to the block is a little roll pin in the OFA. This can be removed, a new hole drilled, and then the OFA can point in any direction you can make fit--you can do this with the early vertical or later horizontal OFAs.

Click to expand...

There it is^^^^^^^^ in a nutshell.

I know everything works with this setup. More or less I'm just trying to reason out if that was was what a prior owner did. I'm just going to assume that's what was done to it unless I find out otherwise. Just makes it a little troublesome when picking up parts trying to discern which parts to order as a '90 and which to order as a '91. But that's why you can exchange parts at the store.

At this point I'm just documenting my thoughts because there's not much left to figure out. THanks for all the help.

I also need a little advice on my transmission problems. In the interest of not flooding the forum I'm going to try posting it in this thread instead of starting a new one. Any advice is welcome as transmissions are kinda me weak point.

To recap it's a '90 XJ Laredo 4.0/aw4/PT 4wd

The transmission doesn't want to upshift on it's own. with the shifter in OD or 3 with the TCU plugged in it will only upshift at very high Rpm if it shifts at all. If I unplug the TCU I can manually shift fine. The TPS has been replaced since. Also I've done 3 switch manual control mod. Have it set up so that one switch controls power on/off for the tcu, second controls TC lockup, third controls 1-2 shift with shifter in 1-2 range. Since I installed this mod I have noticed the following. power to tcu off, shifter in 1-2, 1-2 shift button on/off, doesn't make a difference. stays in first. tcu power off, shifter in 3/od, 1-2 shift button pressed, stays in first gear, when pressed while at speed it acts like it slips then 1st gear engages when RPM's catch up.

Have been doing a little diag with this page (mainly cross checking values between spec and actual from page 3)http://www.transonline.com/transdigest/magazines/1997-10/Shift Pointers/index.html.

Everything reads normal except the following.

C3- key on/engine off -------------5.85 V
C14-Key off/tcu unplugged---------4.6 MOhms
C15-Key off/tcu unplugged---------23.9 Ohms
C16-Key off/tcu unplugged---------4.52 MOhms
D1-Key on/engine off--------------5.5V
D2-Key on/engine off/closed throttle--4.88V
D2-Key on/engine off/open throttle---1.2V

Sorry If it's a little long winded, but I've learned it's always better to get too much info than too little.

You need to figure out if you have renix sensors and computer or the OBD-II HO sensors and computer. The differences are quite obvious near the throttle body. TPS is on the front of the throttle body on Renix, and the back side for HO OBD-II (IIRC). The throttle connections and cables are on opposite sides too as I recall. There are hoards of pictures in various threads here at .

The Renix ECU has RENIX on the box, under the dash upper right side.

As I recall TCU has more than one power wire, one is through the ignition switch and a fuse, the other is some kind of keep alive memory that stays on all the time.

How about getting the number off your cylinder head? That could help narrow things down.