Drivetrain swap

I'm in the process of swapping a complete drivetrain from a 95 xj (4.0/ax15/np231) into an 87 xj (4.0/aw4/np231). I read you can re use almost all the wiring and sensors from the renix system here: http://www.jeepsunlimited.com/forums/showthread.php?t=372106

My question is which crank sensor should I use (87 or 95)? And depending on which one I use, will either one work with the 95 flywheel or do I need a flywheel from a renix era ax15 equipped xj?

Why would you want to stay with the antiquated renix system?

souske said:

Why would you want to stay with the antiquated renix system?

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there's nothing wrong with it, it's quite robust.

You'll need a Renix flywheel and CPS. They do not interchange.

You can simply thread the renix senders into the HO motor, they should all fit. You'll need to adapt the renix TPS to the HO throttle body. There's a writeup somewhere round here. It's a bushing and some drremel time.

The 95 flywheel requires the 91-95 CPS and computer. The 87 flywheel is used only with the Renix CPS and Renix ECU. The flywheels and CPS are totally different and not compatible.

So you need the 87 CPS and 87 flywheel, if I understood what you are doing?

87manche said:

there's nothing wrong with it, it's quite robust.

You'll need a Renix flywheel and CPS. They do not interchange.

You can simply thread the renix senders into the HO motor, they should all fit. You'll need to adapt the renix TPS to the HO throttle body. There's a writeup somewhere round here. It's a bushing and some drremel time.

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Good point on the throttle body sensors. I would swap the Renix manifolds onto the 95 engine with new gaskets to be sure I had good seals, and to avoid all the miss matched throttle hardware issues. IIRC the 95 throttle body is rotated 180 degrees from the Renix?

I'll have to look at the throttle body differences. I figured I would have to run a renix flywheel and cps. I read up on adapting the tps too. I'm just trying to weigh the options of keeping the renix wire harness and ecu or swapping the HO wire harness and computer. It's offroad only so I won't have to worry about turn signals and wipers and little things like that

souske said:

Why would you want to stay with the antiquated renix system?

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Did you do a HO swap into an older xj? If so, any pointers?

Nothing wrong with the renix system. All ya need is a voltmeter. I can think of a dozen of other ems that are total shite.

I think you'd be better off to use the HO manifold and adapt the tos to it. Also 95 had no EGR but that's a minor issue.

Ya, I have no intention of swapping engine hard parts, except for the flywheel. It's basically gonna end up as a full 95 HO motor running on the renix system. Or if I swap the wire harness I won't have to deal with changing the flywheel, modifying the tps, and changing the crank sensor. At this point I kinda feel like swapping the wire harness, I assume it's mostly just plug and play. And that way it'll be a true HO motor running the HO injection

whompinxj said:

Ya, I have no intention of swapping engine hard parts, except for the flywheel. It's basically gonna end up as a full 95 HO motor running on the renix system. Or if I swap the wire harness I won't have to deal with changing the flywheel, modifying the tps, and changing the crank sensor. At this point I kinda feel like swapping the wire harness, I assume it's mostly just plug and play. And that way it'll be a true HO motor running the HO injection

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6 to one, half dozen to the other. Good luck!

whompinxj said:

Did you do a HO swap into an older xj? If so, any pointers?

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Yes, I swapped a 96 OBDII system into an 87 body, and got it certified through the state of CA.

The swap is all plug and play. Get a labelmaker, a notebook, and some sandwich bags. Draw a map as to how things are laid out in the donor, and swap it over piece by piece. If you run into any snags, feel free to PM me

Guessing you are retaining the AX-15?

91 or 96 moved the voltage regulator from the alternator to the ECU!!!!

Renix has an EGR, and electric solenoid. Did the HO have a knock sensor?

The CTS was moved to the T-stat housing in 91 IIRC.

The Renix has a split TPS. Back side of the TPS (square connector) talked directly to the TCU!!!! In 91, HO TPS has one side, only talks to the ECU, and the ECU signals the AW4. IIRC the HO TPS wire voltage pair is reversed as well compared to the Renix TPS?

HO has CEL light, Renix did not.

Gauge cluster issues are possible on the sensor swaps? Oil pressure, vehicle speed, rpm?

The VSS (dash, ECU, AW4, TC...) changed IIRC

So we are all posting away on our win3.1 right?

Sorry about the toes I am about to stomp on but there is no way in hell that the Renix is in anyway close to the OBD1 Chrysler system. More information is readily available, it is easier to work on, and it is more advanced and more stable.

One point in argument, the charging system, the GM CS130 on the Renix sucks, it is not designed for off road use at all, has bearing problems and has cooling problems, although it is a much better that the Paris Rhone crap that was the alternative.

In the past 5 years high end vehicles have given full alternator control over to the ECU, Chrysler developed it in the late 80’s. The fact is the computer system on the OBD 1 is just better, now would I pull the Renix just to swap to the newer system? Hell no! But if I had full running gear, wiring harness, and ECU, without a doubt I would run newer gear. I will admit I would fab in the newer cluster.

However my plan B would be run Mega-squirt FI system, depending on if I was in a free state or communist state, probably do it either way, just more hoops to jump through.

So what do ya say, let’s give win95 a try here?

:twak:

I still have my first IBM XT, and my fathers SWT-80 with the 8" floppies.

Oh, and yes, 4 Renix jeeps and 6 85-89 XJs. None of them are OBD-I.

But I actually prefer my 85 XJ Franken-Diesel, LOL!:laugh3:

And I upgraded my Win 3.1 to Win 3.11

The problem I have with putting the voltage regulator in the ECU is you now get to replace a $$$$$$$ ECU instead of dirt cheap alternator.

I still have the original 87 and 89 OEM ECUs in all my Renix rigs. And in my experience when the OBD systems give you gibberish data, it is time to go back to old school anyway. My son's 96 OBD-II was too dumb to see that one spark plug wire was not even connected recently. It was giving out a missleading lean bank 1 error, LOL!:laugh3:

Ecomike said:

The problem I have with putting the voltage regulator in the ECU is you now get to replace a $$$$$$$ ECU instead of dirt cheap alternator.

I still have the original 87 and 89 OEM ECUs in all my Renix rigs. And in my experience when the OBD systems give you gibberish data, it is time to go back to old school anyway. My son's 96 OBD-II was too dumb to see that one spark plug wire was not even connected recently. It was giving out a missleading lean bank 1 error, LOL!:laugh3:

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Yes my wifes 99 altima recently gave me a pcm internal fault code turns out it was a bad plug wire lol

Ecomike said:

The problem I have with putting the voltage regulator in the ECU is you now get to replace a $$$$$$$ ECU instead of dirt cheap alternator.

I still have the original 87 and 89 OEM ECUs in all my Renix rigs. And in my experience when the OBD systems give you gibberish data, it is time to go back to old school anyway. My son's 96 OBD-II was too dumb to see that one spark plug wire was not even connected recently. It was giving out a missleading lean bank 1 error, LOL!:laugh3:

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well not quite, if regulator goes south you can trick the ECU into thinking it is there so it will not kick a code then run external regulator. anytime we want to run 16 volts we do that.

i have a very old laptop running 3.1 but i cant remember the last time i used it.

i am not bagging the Renix system, it is just the technology is better on OBD 1, but you are not saying the Renix could catch the plug wire, are you?:nono:

I gotta agree with Rush, I don't like RENIX, though it works. Honestly I prefer OBD2 over OBD1... personal preference however. Pick your poison.

I think you might be complicating things though, whompinxj - unless you want to upgrade to the HO electronics, it's optional. You can literally bolt on every single one of your RENIX senders, manifolds (except exhaust - see below), etc onto the motor, stick your AX15 in there, and the only new part you need to buy is a RENIX flywheel. Flywheels aren't that expensive, rockauto has a decent one for $57 brand new. The RENIX auto ECU really won't care if it has a TCU to talk to or not, and the TCU won't really care if you disconnect the AW4 from it and leave it hanging. I ran my 91 with the AW4 disconnected from the TCU for months after my AX15 swap just to see if it would affect anything, then removed the TCU as well, there was no noticeable difference and RENIX cares even less about the TCU than OBD1 HO does.

So unless you WANT to swap to the HO ECU/intake/etc you really don't have to. Just split your donor engine/trans, swap in a RENIX flywheel, bolt it back together, stick your RENIX senders and such on, perhaps swap the distributor and/or cam position sensor (under the distributor cap+rotor), gauge senders, accessories etc onto the block, wire your AX15's reverse light switch into the right pins of the jeep's NSS connector, shunt the P/N pins on the NSS connector (or add a clutch safety switch here if you desire - they didn't come factory till 97).

This thread: http://comancheclub.com/topic/29861-ho-head-on-renix-block-opinions/ indicates you can use RENIX intake manifolds with HO heads, just have to swap to the HO exhaust manifold (to avoid the port mismatch blowing out the manifold gasket) and downpipe, so for that you can either:
* swap RENIX head onto block, use all RENIX manifolds and electronics
* swap RENIX intake and electronics onto complete HO motor, use exhaust manifold and downpipe from donor

Up to you. There's quite a variety of ways you could do this depending on what parts you actually want and which you just think you have to use. Depending on whether you're in smog-check land or not, you could end up with an EGR delete out of this as well, since swapping to the HO exhaust manifold does away with the port for that and leaves you only needing to put a small blockoff plate on the intake manifold port for it.

IMO, the easiest way is to keep the RENIX computer, it's worth having to buy a $57 flywheel to not need to strip down, splice, and rewrap the harness for a few measly horsepower going from RENIX to HO. It sounds like you just want to minimize the amount of work needed to put this all together, so this is probably the route I'd choose.

Rush Power Systems said:

i am not bagging the Renix system, it is just the technology is better on OBD 1, but you are not saying the Renix could catch the plug wire, are you?:nono:

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:nono:, LOL!!!!

I am saying with Renix I would not have been given a wild goose chase code (and followed it to the ends of the earth), a code that all the experts said was one of 4 causes, all of which were wrong!!!!

With Renix I would have used old school methods, and found the problem quickly instead of spending days chasing my tail trying to find non existent phantoms.

The OBD-II should have had sense enough to know it had no spark in the one cylinder, know that it had 100% miss fires in that cylinder. Instead it decided it had another problem (lean code bank 1), and it refused to lock in the emission monitors as a result of the one cylinder missfire (I had replaced the O2 sensors, and reset the PCM), and never once did it give any indication of the 100% missfires in the one cylinder.

I finally discovered the problem with old school stealth methods of Gremlin hunting that Renix GREMLINs :laugh3: taught me, LOL

There is nothing like playing a game where the computer gives you hints and clues, and the first question you must ask is, "Is the computer lying, or confused, or just clueless like me, LOL!!!

96 was really stupid for OBD-II, it had the bare minimum of functionality to meet federal standards basically.

My 98 actually does give me DTCs for individual cylinder misfires, when my head gasket blew between #3 and #4 it persistently indicated that those two cylinders were misfiring. The ECU uses the master timing signal from the CPS to determine which cylinders aren't contributing as much power as they should (and thus which point in the rotation the crankshaft slows down at) and then sets codes for that.

I can see why (lacking the extra CPU power in the later JTEC modules) a 96 would say it was lean on bank 1. It saw that there was more oxygen in the exhaust gases (as it hadn't burned all the fuel due to the lack of spark) and no amount of injecting more fuel would bring the o2 levels down, which indicates a misfire. In the 96 ECUs they just didn't have enough CPU power and hadn't had enough development time to add many of the optional DTCs.