I would also speculate that this was done so the manual transmissions and the autos shared t-cases. until they switched the AW4 to 23 splines, the autos and manuals used differet input gears. all about streamlining your supply chain on that one.j99xj said:
Renix vs. HO (-96)
- Thread starter XJMarty
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90Blue_XJ
NAXJA Forum User
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- In yer postz fixin yer spellinz.
That is another reason that I have heard but the reason that they really changed is probably lost to history. The change could have been to use the same transfer case or the purchase could have been to get it match what AW was selling to the Japanese builders, Toyota or whomever. The bottom line was that Jeep saved a few dollars and the bean counters were happy to comply with what ever the reason was that allowed that savings. Who cares after 17 years anyway? The point is , we as XJ owners, know about the change and take it into consideration when looking for replacement parts for our XJs.87manche said:
XJMarty
NAXJA Forum User
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- Czech Republic
bump!
Ed in North Ga.
NAXJA Forum User
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- Georgia/ Hiawassee
Renix=easier to work on- simple as that.
If you know how. If your starting from scratch, farrrrr easier.
Change the oil, clean the necessary parts- fill with gas, and drive it.
If it wont start, the list of things to check is simplistic-
If an HO wont start...well, that list gets long in a hurry.
If you know how. If your starting from scratch, farrrrr easier.
Change the oil, clean the necessary parts- fill with gas, and drive it.
If it wont start, the list of things to check is simplistic-
If an HO wont start...well, that list gets long in a hurry.
Hey guys,
Just wanted to say excellent thread and thanks for all the intelligent, informative replies!
I've owned an '88 (with Renix of course) for about 3 months now and have enjoyed learning the systems and bringing it back to life. It's only got 114k on it and I hope to drive it well past 200 if the Jeep Gods don't let Murphy sneak up on me. The motor has been simple to work on and diagnose with a multimeter and it runs great now, but I did have to bring it in to a shop at one point and get a few things checked with their Snap-On 2500 scanner because I was having stalling problems I couldn't track down, but their rate was reasonable and I'm glad I did it because I learned even more about the motor through talking about their findings with them.
Overall the parts have been cheap and readily available at NAPA, only dealer items I bought were some new CCV hoses.
The only negative I've found is that there wasn't a "real" FSM in 88 or 89, just some "update pages" to supplement the 87 FSM which isn't cheap (probably because of the demand from 87, 88 and 89!). Not to mention 87 was carb'd and 88 switched to fuel injection, so a big difference in content (although there is a good fuel injection manual out there). I guess I'm just spoiled because the manual for my 79 CJ-5 is so helpful.
Sorry not to contribute much real info on this one, and thanks again for the topic!!
Just wanted to say excellent thread and thanks for all the intelligent, informative replies!
I've owned an '88 (with Renix of course) for about 3 months now and have enjoyed learning the systems and bringing it back to life. It's only got 114k on it and I hope to drive it well past 200 if the Jeep Gods don't let Murphy sneak up on me. The motor has been simple to work on and diagnose with a multimeter and it runs great now, but I did have to bring it in to a shop at one point and get a few things checked with their Snap-On 2500 scanner because I was having stalling problems I couldn't track down, but their rate was reasonable and I'm glad I did it because I learned even more about the motor through talking about their findings with them.
Overall the parts have been cheap and readily available at NAPA, only dealer items I bought were some new CCV hoses.
The only negative I've found is that there wasn't a "real" FSM in 88 or 89, just some "update pages" to supplement the 87 FSM which isn't cheap (probably because of the demand from 87, 88 and 89!). Not to mention 87 was carb'd and 88 switched to fuel injection, so a big difference in content (although there is a good fuel injection manual out there). I guess I'm just spoiled because the manual for my 79 CJ-5 is so helpful.
Sorry not to contribute much real info on this one, and thanks again for the topic!!
Matthew Currie
NAXJA Member #760
- Location
- Vermont, land of big clay
87 4.0 was not carbed. Renix MPI from the get-go. The 2.5 was carbed through 85, and went to TBI in 86. The differences between 87 and 89 4.0 are minimal, mainly in the wiring harnesses and little annoying things like the length of the accelerator cable. The principal parts all interchange.CRJeepin said:
I don't know whether it's still available, but Chilton had a Fuel Injection book that included the Renix, and was not too bad. It includes fairly detailed component tests, etc. It's their part # 7768.
jeepboy381
NAXJA Forum User
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- Gresham, Or
I own a 87, 00, and a 97 XJ and here are my opinions.
I would have to say that Renix Era jeeps are definently not as good as OBD era Jeeps. The renix is an absolute wiring disaster, I can't recal a vehical that looked more horrible under the hood than a renix Jeep! The Renix era cooling system is absolutely horrible unless you throw money at it or change it out to a open cooling system from a OBD XJ. The renix head, throttle body, intake manifold, and exhaust header also do not flow as good as a OBD jeep, that is why mine is all changed to the OBD era parts. On my renix Jeep I broke my Peugot 5 speed the first wheeling trip I took it on, it now has a tranny out of a OBD Jeep. The Renix era brakes suck as well, I have switched my front brakes to OBD era ones and also need to change my brake booster to a 97 and newer one because the renix one is only single diaphram. The 97+ brake booster is a dual diaphram design.
As you can see my Renix XJ is slowely turning into a OBD era XJ, I don't know anyone who puts Renix parts on OBD era XJ's, maybe the engine block? The only pluses to Renix are the better engine block, slightly better fuel mileage, and....... can't think of anything else. One thing I have noticed and liked about my 87 is that the interior still looks brand new, it has held up better than any other vehical I have seen at that age. I can't wait to retire my 87 and build my 00 XJ though.
I would have to say that Renix Era jeeps are definently not as good as OBD era Jeeps. The renix is an absolute wiring disaster, I can't recal a vehical that looked more horrible under the hood than a renix Jeep! The Renix era cooling system is absolutely horrible unless you throw money at it or change it out to a open cooling system from a OBD XJ. The renix head, throttle body, intake manifold, and exhaust header also do not flow as good as a OBD jeep, that is why mine is all changed to the OBD era parts. On my renix Jeep I broke my Peugot 5 speed the first wheeling trip I took it on, it now has a tranny out of a OBD Jeep. The Renix era brakes suck as well, I have switched my front brakes to OBD era ones and also need to change my brake booster to a 97 and newer one because the renix one is only single diaphram. The 97+ brake booster is a dual diaphram design.
As you can see my Renix XJ is slowely turning into a OBD era XJ, I don't know anyone who puts Renix parts on OBD era XJ's, maybe the engine block? The only pluses to Renix are the better engine block, slightly better fuel mileage, and....... can't think of anything else. One thing I have noticed and liked about my 87 is that the interior still looks brand new, it has held up better than any other vehical I have seen at that age. I can't wait to retire my 87 and build my 00 XJ though.
Last edited:
Matthew Currie
NAXJA Member #760
- Location
- Vermont, land of big clay
Somewhere between 88 and 89 they improved the wiring harness, and eliminated that disastrous bulkhead "C-101" connector. It at least looks a little nicer. I agree to some extent about the wiring of the 87, which was always a pain in the neck. Renix seems more sensitive to minor wiring and connector issues. But once you're used to it it seems to keep going all right.jeepboy381 said:
Want to pump up your Renix? Swap in HO injectors (but plan on doubling your trips to the gas pump!) My buddy did that (90 XJ with '91 injectors, thinking they were the same) and it turned into a real tire burner.
I prefer Renix, but for doing a vehicle conversion the HO is easier because it's all under the hood. I've had far more problems with HO systems than Renix (I took apart all my electric connectors when I got my '87 MJ and sprayed them with electronic cleaner) and since I'm approaching the 300,000 mile mark (later this year with the miles I rack up) I think it's proved itself (I also have an '86 MJ 4 cyl that passed the 300,000 mile mark a couple years back and broke the speedo cable but kept going. It's awaiting time for me to put the new motor in)
I prefer Renix, but for doing a vehicle conversion the HO is easier because it's all under the hood. I've had far more problems with HO systems than Renix (I took apart all my electric connectors when I got my '87 MJ and sprayed them with electronic cleaner) and since I'm approaching the 300,000 mile mark (later this year with the miles I rack up) I think it's proved itself (I also have an '86 MJ 4 cyl that passed the 300,000 mile mark a couple years back and broke the speedo cable but kept going. It's awaiting time for me to put the new motor in)
XJMarty
NAXJA Forum User
- Location
- Czech Republic
As I started this thread, I will contribute with my experience. Just tell me what do you think.
I have one renix ´89 (in service) and few renix cars I use as donors. This car is from switzerland, and was maintained well, and only a city DD, now has about 240tkm, It has 33" BFG and 4.56 gears, I have ocassional stalling problems, rough idle and constant lack of power - I have to pust the throttle realyl hard to keep up with traffic, mpg about 12?. I suspected many things including clogged cat, nothig really serious showed up, I changed TPC, oxygen sensor, and did a regular tune up. Nothing really helped, it is not my DD so I did not went really deep into it.
Last september I had a really terrible nightmare startin with no recharge from alternator, and ended with buing a new alternator + scouting almost every wire in the car, icluding the damned fusible links
Now it recharges quite fine, but the other problems persisted.
On the other hand I have a ´93 HO, which was used in a coal surface mine by miners. I use it as a competition rig in stock class of our national championship. It has about 130tkm, and it service was next to none for its whole life, It was terribly rusted through and completely badly maintained. But the engine runs really strong, and I did not have any electrical related problems with it ever. It stays out for the whole year, and sometimes I wash it with pressure washer even inside (capets and upholstery is gone). The idle is perfect.
The point is that nobody here (I mean Czech republic) really understand the jeep wiring and electro, so I was thinking if the HO would be easier to maintain for me in the long run....
I have one renix ´89 (in service) and few renix cars I use as donors. This car is from switzerland, and was maintained well, and only a city DD, now has about 240tkm, It has 33" BFG and 4.56 gears, I have ocassional stalling problems, rough idle and constant lack of power - I have to pust the throttle realyl hard to keep up with traffic, mpg about 12?. I suspected many things including clogged cat, nothig really serious showed up, I changed TPC, oxygen sensor, and did a regular tune up. Nothing really helped, it is not my DD so I did not went really deep into it.
Last september I had a really terrible nightmare startin with no recharge from alternator, and ended with buing a new alternator + scouting almost every wire in the car, icluding the damned fusible links
Now it recharges quite fine, but the other problems persisted.On the other hand I have a ´93 HO, which was used in a coal surface mine by miners. I use it as a competition rig in stock class of our national championship. It has about 130tkm, and it service was next to none for its whole life, It was terribly rusted through and completely badly maintained. But the engine runs really strong, and I did not have any electrical related problems with it ever. It stays out for the whole year, and sometimes I wash it with pressure washer even inside (capets and upholstery is gone). The idle is perfect.
The point is that nobody here (I mean Czech republic) really understand the jeep wiring and electro, so I was thinking if the HO would be easier to maintain for me in the long run....
JoeOffRoad
NAXJA Forum User
- Location
- Vancouver, WA
Wow said:
--- way to prove your point...
Both systems are pretty good. The renix system seems to be down right bullet proof with a few modifications (cooling system, etc). I have run both, and could go either way.
BillBraski
NAXJA Forum User
- Location
- Appleton, Wi
Ed in North Ga. said:
What about that good old t-60 bolt on the oil filter adaptor?
Matthew Currie
NAXJA Member #760
- Location
- Vermont, land of big clay
My Renixes ( do pedants say Renices?) had plain hex head bolts. Easy! The 95 has that damn T-60. So does the 99, I think, but by some incredible stroke of luck, my 99 has not started to leak yet, even at 194K miles!89xj said:
Mine had a hex head too 
Also should mention I converted over to open cooling when the radiator started leaking. Easy to do and worthwhile since I had to replace the radiator anyway, but the Renix closed system was cooling the engine just fine up until that point.
Also should mention I converted over to open cooling when the radiator started leaking. Easy to do and worthwhile since I had to replace the radiator anyway, but the Renix closed system was cooling the engine just fine up until that point.
Ecomike
NAXJA# 2091
- Location
- MilkyWay Galaxy
If you must pass emission tests, the 96 and newer HOs 
laugh3. no not require actual tail pipe testing as the OBD-II computer replaces the annual tail pipe test. All the inspection does is check with the OBD-II computer to see if it is happy. If the OBD-II computer is not happy with anything it does not matter how clean your tail pipe emissions really are. This can be a real PITA when it starts doing wierd things that do not make any sense, like saying a brand new O2 sensor is bad!
The Renix era, and OBD-I, 91-95 jeeps require real tail pipe emission tests, at least here they do. But they don't care about what the computer (Renix or OBD-I) thinks. I passed the latest emissions test with no Knock sensor installed on my 87.
I suspect that volt-ohm meter testing is much easier on the Renix than the newer models. No scanner needed. All your really need with Renix is a volt- ohm meter and a wiring diagram / FSM to diagnosis just about any electrical or electronic problem. OBD-I and OBD-II get more complex with diagnosis when it throws an idiot code that makes no sense and does not match the external meter testing data.
If I was a shop mechanic, or shop owner I would prefer OBD-II as most repairs would go faster and most diagnostic work would be faster and easier for repir shop trainees, until one of the problem vehicles arrived.
When the computer looses sensor signals, or sensors I suspect the Renix is easier to run and troubleshoot, and in some cases easier to keep driving until repairs are completed.
laugh3. no not require actual tail pipe testing as the OBD-II computer replaces the annual tail pipe test. All the inspection does is check with the OBD-II computer to see if it is happy. If the OBD-II computer is not happy with anything it does not matter how clean your tail pipe emissions really are. This can be a real PITA when it starts doing wierd things that do not make any sense, like saying a brand new O2 sensor is bad!The Renix era, and OBD-I, 91-95 jeeps require real tail pipe emission tests, at least here they do. But they don't care about what the computer (Renix or OBD-I) thinks. I passed the latest emissions test with no Knock sensor installed on my 87.
I suspect that volt-ohm meter testing is much easier on the Renix than the newer models. No scanner needed. All your really need with Renix is a volt- ohm meter and a wiring diagram / FSM to diagnosis just about any electrical or electronic problem. OBD-I and OBD-II get more complex with diagnosis when it throws an idiot code that makes no sense and does not match the external meter testing data.
If I was a shop mechanic, or shop owner I would prefer OBD-II as most repairs would go faster and most diagnostic work would be faster and easier for repir shop trainees, until one of the problem vehicles arrived.
When the computer looses sensor signals, or sensors I suspect the Renix is easier to run and troubleshoot, and in some cases easier to keep driving until repairs are completed.
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