renix to bendix

hi im trying to switch my 86 xj renix to a newer HO bendix. the reason is because i want the ob1 to be able to tune it better. now i was wondering if anybody had any links that would tell me what the wires running on the big connector on the fire wall belong too. I have a 92 ho xj thats totalled and it has the same big connector and i dont know if its the same. so if anybody can help me i would apriciated.

dss said:

hi im trying to switch my 86 xj renix to a newer HO bendix. the reason is because i want the ob1 to be able to tune it better. now i was wondering if anybody had any links that would tell me what the wires running on the big connector on the fire wall belong too. I have a 92 ho xj thats totalled and it has the same big connector and i dont know if its the same. so if anybody can help me i would apriciated.

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If you have a 1986, you're going to have trouble putting in an OBD-I 4.0L. The OBD-I 2.46L will be easier for you (the front clip was extended in 1987 to make room for the longer 242ci engine.) Not saying it's impossible, mind - just damned difficult.

1986 has a couple of possibles for what you've got - if you've got a carburetted four-cylinder, it may not even be RENIX. If you've got a TBI four, you've got early RENIX. If you've got the V6, you've actually got GM OBD-I controls.

Can you tell us any more about what you've got?

Not to hijack, but I have a 91 4.0 and and an 89 with a 4.0. I was wondering what the pin outs for the large firewall connector are also, to see about putting the 91 motor into the 89. Any help for me also?

Check my XJOG and RENIXPower groups - I've been putting wiring diagrams up there as I scan them. I don't know if I have bulkhead pinouts up there, but it's possible. I haven't a scanner, so if I do have them (which is probable,) I won't be able to get them scanned - but if no-one else can help you, let me know and I can make copies to mail to you.

Oh - and I forgot to mention. RENIX is Bendix-built (you probably already knew that,) but it got replaced with Chrysler electronics in 1991. The only Bendix you'll find on an XJ after that will be the brakes. Just thought I should clarify that for you - I've no idea offhand who did build Chrysler electronics (tear the module apart, and you can probably find out) but it wasn't Bendix...

Although, I'd either go with OBD-II (for programmability) or RENIX (for sheer flexibility) over OBD-I anyhow. A system mandated by the State of California is going to be flawed from the off...

Almost forgot (although links should be on my site as well...)

groups.yahoo.com/group/XJOG
groups.yahoo.com/group/RENIXPower
groups.yahoo.com/group/JeepPower

my 86 xj is a 4.0. the reason im going with this is because i got the whole 91 xj for cheap. i was lookink at hesco and their conversion kits but they where too much money. i would like the new system because its ob1 and i stroked the motor out and i dont feel the renix fuel injection is delivering the out put it deserves. also i now that the make computer chips for the newer crysler computer. and like i was saying i think it would be easier to tune it.

dss said:

my 86 xj is a 4.0. the reason im going with this is because i got the whole 91 xj for cheap. i was lookink at hesco and their conversion kits but they where too much money. i would like the new system because its ob1 and i stroked the motor out and i dont feel the renix fuel injection is delivering the out put it deserves. also i now that the make computer chips for the newer crysler computer. and like i was saying i think it would be easier to tune it.

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If your 86 is a 4.0 and truly an 86 and not 87, someone must've swapped it in. I know 1986 was the year they changed the motor mounts and such in prep for the 4.0, but they didn't actually use them until 1987. If you want computer chips and easy to tune like 5-90 said, go OBD-II. I don't think there are even chips out there for the OBD-I system (that I've ever seen) and that thing was a pain to pull codes from anyway. At the same time since you have an OBD-I sitting around I guess you could use it, I would just advise against it.

my bad its actually an 88. well to reply i have found the chips, plus i think it would be more money to swap to ob 2. but truly u dont think swaoing to obd 1 is not a good a godd idia. i know that crysler started to do a good job with their codes and data list in early model vehicles, if u have the right scan tool that can pull the codes and the datalist.

dss said:

my bad its actually an 88. well to reply i have found the chips, plus i think it would be more money to swap to ob 2. but truly u dont think swaoing to obd 1 is not a good a godd idia. i know that crysler started to do a good job with their codes and data list in early model vehicles, if u have the right scan tool that can pull the codes and the datalist.

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Yeah and it's completely up to you man but you could get a fusebox/wiring harness out of a 96 which had the same main fusebox location (on the firewall) as your 88 and you'd be stepping up to OBD-II. Ultimately though you're the one who's doing it and it has to be your decision.

Keep in mind, most of the sensors will need to be changed over too.

dss said:

my bad its actually an 88. well to reply i have found the chips, plus i think it would be more money to swap to ob 2. but truly u dont think swaoing to obd 1 is not a good a godd idia. i know that crysler started to do a good job with their codes and data list in early model vehicles, if u have the right scan tool that can pull the codes and the datalist.

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I didn't say it was a "bad" idea outright - just that there's a better option for you to use. The key difference is that OBD-I was originally specified by the State of California, so there was little homogenization of standards from inception to, say, 1992 or so. OBD-II was specified by SAE - so you've got commonality of systems, and everything (except the communications bus itself) is standardised. Also, OBD-II is ongoing, so there is more aftermarket support for performance tuning. Consider what you're trying to do - it may be worth the money to get an OBD-II setup from a rollover, even though it would require more work to install (and getting the gage cluster to fit would be a pain, I'm sure - but the OBD-II instruments get their data from the CAN bus.)

You would have to change sensors, and other small parts as well (like the OBD-II CTS goes in the thermostat housing, and therefore expects readings it wouldn't see from the one in the cylinder head or the one behind the exhaust manifold.) The HEGO sensors are damn sure different (different chemistry entirely!) and the MAP and TPS will probably want changing as well. Simplify things - swap out the entire top end (cylinder head, manifolds,) since the later heads breathe better. 1991-1999 heads should work with OBD-II - don't bother getting the 0331 head (1999/2000-2007) unless you get a DIS OBD-II system - and even then, DIS can be adapted to an 0630 or 7120 head - there's a thread here on it. The 0331 head does have some trouble with cracking, and I've not yet been able to dig up numbers on "revised" 0331 heads and how to spot them just yet. Information on that is here as well - a good search string to try would be <0331 club> or <0331 head>.

Either way, the conversion will be a fair amount of work, since the OBD instruments respond to different sensor signals (OBD-I) or to simple serial data from the engine controller (OBD-II.) You're probably going to have to change all the wiring from the driver's seat forward, including IP wiring. Are you up to the task?





OBD - OnBoard Diagnostics. OBI-I (1995 and earlier,) and OBD-II (1996 forward) are current iterations
DIS - Distributorless Ignition System
HEGO - Heated Exhaust Gas Oxygen (sensor)
TPS - Throttle Position Sensor
MAP - Manifold Absolute Pressure (sensor)
CTS - Coolant Temperature Sensor
IP - Instrument Panel
SAE - Society of Automotive Engineers
EOL - End of (production) Life

#2686 - "RENIX" 4.0L Head - 1987-1990
#7120 - 1st Gen OBD-I head - 1991-1995/6
#0630 - 1st Gen OBD-II head - 1995/6-1998/9
#0331 - 2d Gen OBD-II head - 1999/2000-2007 (EOL) Featured drilled/tapped bosses for DIS coil rail, and can be prone to cracking between #3 & #4 cylinders.

ah, yeah im always up for a good challenge, and i wpould say with access to mitchell on demand 5 the whole obd codes should be a problem. plus the whole messing up with the IP does not interst me alot, the ecu on the older jeeps was inside but the newer have it outside, so the only problem i was really seeing was that connector to hook up the new ecu to tcu under the dash.

dss said:

ah, yeah im always up for a good challenge, and i wpould say with access to mitchell on demand 5 the whole obd codes should be a problem. plus the whole messing up with the IP does not interst me alot, the ecu on the older jeeps was inside but the newer have it outside, so the only problem i was really seeing was that connector to hook up the new ecu to tcu under the dash.

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I don't recall when, but ChryCo integrated the TCU into the ECU to make a SMEC - I'm wanting to think that was in 1996 (when they went OBD-II,) but I'm not sure - it may be late OBD-I (1994/1995?) as well.

You may be able to swap to OBD-I without rewiring the entire IP, but it's still going to be a headache. As you said, you've got the RENIX ECU by your right knee - the SMEC is usually underhood. I honestly can't tell you offhand where the TCU is on OBD-I XJs. Perhaps someone here can, and enlighten both of us?

I do have OBD-I and OBD-II codes for XJ listed (culled from FSMs.) I'd like to have a compleat listing of OBD-II codes, I'll have to get around to that. However, a compleat listing of OBD-I codes becomes prohibitive.

If you want, check out my RENIXPower and XJOG groups - I've got a few wiring diagrams up there, and you could get an idea of what you need to do. I may even have them up for your years! It's worth a shot, since both groups are free...

groups.yahoo.com/group/RENIXPower
groups.yahoo.com/group/XJOG

The main question I'd have for you, however, is simple - what are you trying to do, exactly? I know you're looking for tunability that can be offered by going to OBD, but I still think you're going to be better off going to OBD-II instead of OBD-I (IMO.)

ah, well i am up to the task, the only problem that i was seeing was that connector to hook up the tcu to the new ecu. i have the whole car with all the sensor and wires.

i thougt the last post didn't reply. but my xk does have a tcu it right on top the pass knees. the only thing thing was that the tcu is connected to the tps on my tru a separate connector, it has one sort of end shaped and the other scuare, i know the square hooks up to the tcu for shifting purpuses. i have that manual shifting switch, that lets me stay on 1st gear as long as i want, but i dont know on the newer one cause it only has one connector and thus, i dont know if that wire splits or the ecu actully tells it.

As I recall, the OBD-I TCU gets its throttle information from the ECU (rather than on its own, as per RENIX.) Thus, the "single-output" TPS.

The RENIX TPS is two units in one casting - working in opposite directions. The ECU side goes from high resistance to low, and the TCU side from low to high (I think - I may have that reversed.) I've not compares OBD-I/II TPS function to RENIX to figure out if they reversed the engine side to keep up with the TCU, or if the ECU sends a separate output, so I can't help you much there.

I still say it's going to be a whole mess of work for what you're likely to gain from it, which is why I posed the question - "What, exactly, are you trying to accomplish?" There may be an easier way for you to get there. It's not that I don't want to help you - I would just like to make sure there isn't likely an easier road for you to follow...

well i do alot of short sand drags and some races up hill, over here in arizona we dont have much rocks, but we do have alot a sand. I already a a stroker in the jeep, and bigger for injectors, a im running a little bi os nos. but the thing its not enough for me, like ricky boby said, in his movie, i like to go fast. i found some jet per stage two chops on line, and weel of couse the make the bigger throtle bodys for it and this jeep that i came across was cheap, and i said well, it might not be a bad idea and the new electronics, might help it out, so i got this jeep oping it would help a little, and trust me i know, ob2 is way better, well for many reasons u listing some good ones, but this car is not a daily driver, and im also in the process of rebuilding a 86 chevy k10 pickup, and well for the money this 92 ho xj seem good.

I put a 93 OBD1 4.0L into an 89 Renix 4.0L system. It wasn't very hard to do & it gained a bit of power over my tired old motor. Here is a link to my write-up & other helpful links:
http://www.terrainstompers.com/forum/viewtopic.php?p=27

I don't think a complete harness swap would net you hardly any more power & it would require a LOT more effort.